Andalus Proton Therapy Center

 

Clinical and Technical

Specifications

First Edition (8/11/2014)

www.andalus-ptc.com

Prepared by

Dr. Maan Ammar (Professor)

Scientific consultant

AU Scientific Harvest (8/11/2014)

 

 

Maan Ammar Date of Birth: 1953 This email address is being protected from spambots. You need JavaScript enabled to view it.

He received BSC in Electronic Engineering from Damascus University in 1977 and attended a training course on design, operating and maintenance of sounder equipment station at Barry Research Corporation, Sunnyvale, Silicon Valley, California in 1977-1978.

He Received MSc in information science and PhD in Information Engineering from Nagoya University, Nagoya, Japan in 1986 and 1989, respectively. He is professor at the department of Biomedical Eng. Dept., Damascus University since 2003. He was the head of department for 8 years (1995-2001, 2007-2009). His achievements in the department attracted the attention of the highest level in the country.

He Taught 10 subjects in the fields of Image Processing, Artificial Intelligence, Knowledge-Based Systems and System Analysis and Design, for last year undergraduate, Master and Doctor students in Computer Science and Information Systems departments at Jordanian Universities in the period 2001-2006.

He stayed as visiting professor at Nagoya University, Japan, (this university received 3 Nobel Prizes in the last 13 years), in the period Oct. 2009-Feb. 2010. They asked him for an Invited Lecture to explain how he could transfer his PhD research into a commercial system with USA and International patents, that detect forgery signatures in checks and serves tens of banks in the 50 states of the USA. The lecture was delivered on Feb. 19, 2010 for 150 minutes.

He wrote and translated 5 books published locally, regionally and one of them internationally. He Published 30 papers in refereed journals and conferences, most of them are international.

In 2011, he published a unique research in the International Journal of Pattern Recognition and Artificial Intelligence (IJPRAI), about developing a new decision making technique that surpasses what was considered as the maximum limit, for decades. He is the cofounder of Asvtechnologies Inc. Company, NY, USA, which exploits his invention.

 

 

Table of Contents

Title

page

Summary

4

Introduction

5

General Information and Conditions

7

Clinical Specifications for the APTC Treatment Facility

8

APTC Performance Specifications

10

Proton Medical Facility in General

11

Accelerator System

14

Beam Transport System

18

Treatment Beam Line (Nozzle)

24

Integrated Treatment and Accelerator Control System (ITACS)

27

Treatment Ancillary Facilities

56

References

73

Reflated articles and reports

76

 

Summary

This technical specifications book summarizes the clinical specifications of the Andalus Proton Therapy Center (APTC) and the performance specifications of technical components for the APTC as required by the clinical specifications. The technical items specified include: the accelerator; the beam transport system including rotating gantry; the treatment beam-line system including beam scanning, and dosimetric instrumentation; and an integrated treatment and accelerator control system. Also included are treatment ancillary facilities such as diagnostic tools, patient positioning and alignment devices, and treatment planning systems. The facility specified will accommodate beam scanning enabling the three-dimensional conformal therapy delivery.

This book represents the start point for discussions with the vendor(s) about the details of the APTC. Every item in this book is discussable for our final purpose of building the PTC with the best performance and conditions.

For any notes about this book, you can write (with thanks) to Dr. Ammar using this email address This email address is being protected from spambots. You need JavaScript enabled to view it. .

Introduction

The knowledge about proton therapy field has been a rather well established one after 25 years of work and development in hospital based therapy centers. The performance specifications of the technical components of the APTC presented in this book are based on the works of famous centers like the LBL, and oriented towards our needs in Andalus Center.

We made our best to make the specifications general, not directed to a particular technology or a specific machine. It is believed that all technologies available today meet all the requirements presented, but the challenge will be in making the requirements meet a specific budget with acceptable conditions.

The complete technical performance specifications are presented in this book. They are arranged as follows:

Section 1: the APTC proton medical facility in general

Section 2: the accelerator system

Section 3: the beam transport system including the gantries

Section 4: the proton treatment beam lines (nozzles) including beam-delivery systems and monitors

Section 5: the integrated treatment and accelerator control system

Section 6: ancillary facilities including the therapy planning

However, the treatment-room associated ancillary facilities, such as patient setup room, immobilization pod storage room, treatment console area for radiation therapists, patient waiting, dressing rooms, and other facilities, are not specified in this book as they should be specified in the Building Specifications Document of the facility.

These performance specifications have the same weight as the Clinical Specifications, and when a conflict exists, the tighter requirement should be adopted.

 

General Information and Conditions

 

Name: Andalus Proton Therapy Center (APTC).

Management and Supervision: A general board from top 5 Syrian Universities:Damascus, Aleppo, Tishreen, Albaath, and Al Andalus University for Med

ical Sciences (private).

Location: Al Qadmus, Tartous, Syria.

General Specifications of the System

· A multi-room Proton Therapy Center.

· Three rotating gantry treatment rooms, one horizontal fixed-beam treatment room, and one research room.

· Organs and tumors to be treated: all possible organs and tumors, with priority to Lung, bladder, breast, cervical, and lymphocyte.

· Therapy capacity: 1200-1500 patients per year.

Supplier

1- One primary supplier for all equipment.

2 - The supplier is responsible for all installations and connectivity issues.

3 – The supplier must sign a maintenance contract for 10 years.

Clinical Specifications for the

APTC Treatment Facility

CS-1 Range in patient: 3.5 g/cm2 - 32 g/cm2 for fields smaller than

22 cm x 22 cm.

CS-2 Range modulation: Steps of 0.5 g/cm2 over full depth

Steps of 0.2 g/cm2 for ranges <5 g/cm2

CS-3 Range adjustment: Steps of 0.1g/cm2

Steps of 0.05 g/cm2 for ranges <5g/cm2

CS-4 Average dose rate: 1Gy/min for 25 cm x 25 cm field at a depth

of 32g/cm2

CS-5 Time structure of the extracted beam: Suitable for beam scanning: "beam on" for more than 50% of time and number of protons in a "spike" <1 x 106

CS-6 Field size: Fixed beam: > 40 cm x 40 cm

Gnatry beam > 26 cm x 20 cm

CS-7 Dose compliance: ±2.5 % of the prescribed dose over

treatment field

CS-8 Effective SAD: >3 m (for gantry)

CS-9 Distal dose falloff: 0.1 g/cm2 above range straggling

(80%-20%)

CS-10 Lateral penumbra : 2 mm over penumbra caused by multiple

scattering (80%-20%)

CS-11 Delivered dose accuracy : ± 2%.

 

APTC

Performance Specifications

1- Proton Medical Facility in General

1-1-Treatment Rooms

At least one gantry room and the fixed-beam room must be provided in the initial phase.

1-1-1- The horizontal fixed-beam room: The horizontal fixed-beam room must be designed so that small-field treatments (e.g., for eye treatment) and the large field (up to 40 cm x 40 cm) treatments can be performed. The equipment switch between the eye treatment and the large field treatment must be <10 min.

1-1-2- The rotating gantry room: The rotating gantry room must be designed to provide 26 cm x 20 cm fields. Together with the couch specification [6.3.7], the facility must be able to irradiate any part of the patient from any direction.

1-1-3- Beam orientations: Fixed for horizontal beam and 4 π steradian for gantry beam.

1-1-4- The treatment room associated ancillary facilities: For each treatment room, there must be a patient setup room, a patient equipment storage area, a treatment console area, etc. (specified in the Building Specifications Document of the facility).

 

1-2- Facility availability

The entire facility shall be available for treatment at least 95% of the scheduled facility-use time ( treatment must be given in 95% schedule with a minor delay of no more than 5 minutes).

1-1- Treatment beams

 

1-1-1- Beam delivery systems: Active (scanning) beam delivery system must be provided.

1-2- Dosimetry reproducibility

±1.5% (2.s.d.) for one day and

±3% (2.s.d.) for one week

1-3- Control system

1-3-1- Treatment control system: The proton medical facility control system must control and/or interface to the accelerator, safety systems, beam lines, treatment rooms, dosimetry systems, patient positioners, and beam modifying devices. The system should permit pulse-to-pulse and within-a-pulse control of the accelerator, pulse-to-pulse monitoring of dosimetry, rapid beam switching and efficient facility startup and shutdown. See [Sec.5].

The time and number of operations needed to operate all components of the facility should be minimized so that operators need only enter the minimum amount of information necessary to specify the desired state of the system. In general, the control system should permit the following operations to be performed in a timely manner (also see [2.4.2]):

1. startup at the start of the day from standby status in < 60 min.

2. startup from a cold start (with good vacuum) in < 120 min.

3. shutdown at the end of the day to standby status in < 15 min.

4. manual setup of all parameters needed for treatment in one room (excluding adjusting gantry angle and beam-modifying devices) in <1 min.

5. automatic setup of all parameters (from a pre-stored table) needed for treatment in one room (excluding adjusting gantry angle and beam-modifying devices) in < 0.5 min.

6. time required to shut the beam off after a HALT (see [5.12.1]) is requested should be very short (~ 10 µ sec)and the time to restart treatment after a HALT should be < 2 sec.

7. time to terminate treatment ("soft" emergency off) must be the lesser of 1 sec or 0.2 Gy delivered dose.

1-4- Radiation safety of the facility

1-4-1- Radiation levels inside and outside facility: Shielding designs must appropriately protect personnel working in the facility (radiation workers) as well as non-radiation workers and visitors. Patient exposure outside the designated treatment fields should be kept within regulatory limits. Principles of ALARA must be applied.

1-5- Operation costs

 

1-5-1- Low operation costs: Operating costs for the facility must be kept at the lowest possible level. The operating costs include the utility costs, maintenance costs (both personnel and parts), and operating personnel costs.

2- Accelerator System

2-1- Energy

2-1–1- Energy range : 70-250MeV protons at the gantry exit measured with the beam monitors used during patient treatments, but before the vacuum exit window [see 3.5].

2-1–2- Time to Establish a New Extraction Energy: Next pulse or one second.

2-1-3- Energy Precision: The energy will be within ± 0.4 MeV of the requested energy over the entire range.

2-1-4- Energy variability: the resolution of the energy-determining system will be no greater than ± 0.4 MeV over the entire range.

2-1-5- Energy Spread: ≤± 0.1 % FWHM at exit of gantry at 100 MeV and up, measured with the beam monitors used during patient treatments, but before the vacuum window.

2-1-6- Energy Variations of Extraction: ≤± 0.1 %

 

2-2- Beam Intensity

2-2-1- Beam intensity(dN/dt): 1011/second at 200MeV, averaged over one cycle at end of gantry, including all losses in the transport system with the usual monitors required to be in the beam used during patient treatment, measured upstream of the vacuum exit window in the gantry.

2-2-2- Microscopic (r.f.) Duty Factor: Full modulation by r.f. in the MHz range is acceptable.

2-2-3- Undesired Beam Intensity Modulation: Acceptable time structures in extracted beam are specified below for scanning mode.

2-2-4- Beam Intensity Modulation Capability Within Pulse: Minimum implementation: no modulation needed -variable velocity scanning used. Upgrade path: 100:1dynamic range down from rate that produces maximum intensity, with bandwidth from d. c. to 5 kHz.

2-2-5- Pulse-to-Pulse Selection of Beam Intensity: 1000:1variation of circulating beam intensity from pulse-to-pulse specified by data arriving no less than 0.1 second before injection with ±10% accuracy at the 108/second average intensity level, increasing in accuracy to ± 2% at the 1011/sec. average intensity level.

2-2-6- Beam ABORT Time: ≤ 10 µ seconds to completely shut off beam after a trigger signal is received.

2-3- Quality of Extracted Beam

2-3-1- Transverse Emittance: ≤ 0.5 π cm-mrad , rms, un-normalized, at 200 MeV, at accelerator exit.

2-3-2- Position and Angle Stability of extracted beam: Extracted beam, measured at synchrotron exit, must not vary by more than ± 1mm or by ±1 mrad during the pulse, or between pulses at the same energy. See [Sec.3].

2-4- Accelerator Beam Monitoring

2-4-1 Monitoring of Beam Circulating in Synchrotron: Primary beam monitor must operate down to 5 x 106 circulating protons with an accuracy no worse than ±10%, improving in accuracy to no worse than ± 2% at 108 or more circulating protons.

2-4-2 Time to recover from various shut-down conditions: Time to start up or shut down from various conditions, are specified in the table below.

Time to recover from various shut-down conditions


3-Beam Transport System

3-1 Beam Energy

3-1-1 Beam energies and transmission: The transport system must be able to handle beam energies from 70MeV to 250MeV.

Proton beam energies:

· into the fixed-beam treatment room: 70MeV -250MeV

· .into the gantry treatment room: 100MeV-250MeV

 

3-1-2- Transmission efficiency and beam size: The transmission efficiency through the transport system should be maximized to lower the peak intensity (dN/dt) requirement of the synchrotron itself and reduce activation and secondary particle production along the beam line.

3-1-3- Beam dump: A beam dump must be provided near the accelerator for tune-up when required.[2.2.8]

3-1-4- Instrumentation of the transport lines and the beam dump: The beam dump and the transport line to the beam dump must be sufficiently .instrumented, including radiation monitors, to debug and develop accelerator and extraction system.

3-1-5- Continuous vacuum from accelerator to last window: All material in the beam line must be minimized to preserve the beam emittance.

3-2- Beam Parameters

3-2-1- Emittance at Gantry Exit: ±1.0 π cm-mrad, rms, un-normalized, at 200 MeV, measured with the beam monitors used during patient treatments, and before the vacuum window.

 

3-2-2- Beam parameters at the isocenter in treatment room: The beam characteristics must be within the specifications listed in the table below for proton beam energies between 150and 250MeV.

Beam specifications at the isocenter:

 

3-2-3- Beam parameters at the gantry entrance: At the rotation point of the gantry entrance, the transport system must provide a round beam with identical emittance and betatron functions in both planes.

3-3- Beam Switching and Tuning:

3-3-1- Transport Line Tracking: The entire transport system through the gantry as well as the scanning system must track the pulse-to-pulse energy variation of the synchrotron.

 

3-3-2-Time to tune beam between treatment rooms: The beam switching time from one treatment room to another must take <1 minute.

3-3-3 Beam-energy change during a treatment: For beam-energy change, the next beam energy must be available on the next synchrotron pulse. See [2.1.2].

3-3-4- Automatic beam tuning: After the initial daily setup and calibration nomanual tuning or beam centering at the isocenter should be necessary when switching treatment rooms or changing the beam energy or gantry angle.

3-4- Gantry

3-4-1- Physical specifications of gantry: The gantry must accommodate a scattering as well as a scanning system. Its performance must meet the specifications listed below.

3-4-2 Drift space in the gantry: The source-to-isocenter distance for a scattering system or the equivalent distance for a scanning system must be larger than 3 m.

3-4-3 Conformation of gantry rotation center to isocenter: The mechanical stability of the gantry under rotation must maintain the crossing points of the central beam axes within a 1 mm diameter sphere.

3-5- Beam Diagnostics, Monitoring, and Safety:

3-5-1 Beam Diagnostics and monitors in Beam Transport System: Diagnostic elements for facilitating a fast and straightforward beam tuning procedure must be provided throughout the beam transport system. Parameters to be measured at one or more points are the beam intensity, the beam centroid, the beam profile, and the emittance. The details of the required monitoring are listed in the table below. Also indicated in the table is the need for floating jaws. Monitors must also be provided to verify the proper working of systems, such as vacuum, radiation, temperature, and other systems

 

Locations of beam monitors and floating jaws.

3-5-2- Materials in the beam line: The material in the beam line due to monitors must be minimized.

3-5-3- Beam Halt I Abort: Beam halt/abort time after detecting a crash condition: time to clamp the beam (t <10 µsec; time to insert beam plug < 5 sec.

3-5-4- Monitoring of Beam in Transport System: Monitors for a fast (t < 10 µsec) detection of beam misalignment due to failures in the accelerator or beam transport system must be provided.

3-5-5 -Monitoring of Beam Transport System Components: The beam transport system must be monitored at all times while a treatment or a calibration procedure is in progress.

3-5-6-Beam Energy Verification: An independent method of beam energy [2.1] verification must be provided. The most direct and primary method for measuring the beam energy is preferred.

3-5-7- Gantry Safety: Safety features which prevent a collision between the patient couch and the nozzle must be provided.


1- Treatment Beam Line (Nozzle)

4-1-Specifications for nozzle using scanning

1-1-1- Dose compliance: The dose compliance must be such that for each point inside and outside the target volume, the dose is within ±2.5% (2 s.d.) of the .intended value [Cs-7].

1-1-2- Permissible beam spot size: The maximum permissible beam diameters at isocenter are: sigmabmax = 6mm at a beam energy of 250MeV, and sigmab max = 10 mm at 120 MeV, where sigmab is the width (80%-20%) of the beam in air at isocenter. A linear interpolation is to be applied at intermediate beam energies.

1-1-3- Length of scanning magnets: The total length of a scanning magnet must be less than 0.5 m. The aperture must clear the beam.

1-1-4- Voxel scanning system:

· The uncertainty in the beam spot position due to the scanning system must be less than 0.5mm.

1-2- It must be possible to position the Bragg-peak in the target volume in 5 mm or smaller steps in all directions, i.e., the available voxel size must be less than 5mm x 5 mm x5mm.

1-3- Beam Monitoring: Beam positions, profiles, and other attributes must be measured and monitored at specified position on the beam line during the beam tuning, calibration processes, and actual treatments as specified below.

4-3- Scanning Dosimetry: Three independent dosimeters that will provide continuous monitoring of the dose delivered to the patient are required.

· One dosimeter has to be located at a distance of less than 1 m from isocenter.

· At least one dosimeter must not saturate at the highest possible beam current focused into a 3 mm2 area. (A secondary electron emission monitor (SEM) fulfills this requirement.)

· A dose detector with a two-dimensional position resolution of 5 mm or better must be provided. The detector must be able to generate a beam cut-off signal when any one spot has reached the specified dose limit. It can thus serve as one of the three independent dosimeters.

1-4- Beam energy modification: The range of the protons must be changed during the treatment covering 16 g/cm2 in 0.5 g/ cm2 steps by changing the energy of the extracted beam from the accelerator. See [2.1.4].

1-5- Safety: Whenever an "out of tolerance" condition [4.1.2] is detected, the beam must be cut off before additional 5% of the treatment dose is delivered to any one spot in the treatment volume.

1-6- Other Nozzle Hardware

4-5-1- Monitoring of positions of beam-modifying devices: All devices which can be physically moved, such as beam monitors, and can possibly interfere with the beam and alter the delivered dose distributions must be interlocked or monitored for correct positioning in software and hardware.

4-5-2- Collimation for patient safety: Collimation devices, like multi-leaf collimator, are necessary in order to provide passive protection for the areas outside the target volume.

5- Integrated Treatment and Accelerator Control System (ITACS)

5-1- Control System

Following acronyms are used:

TCS: treatment control subsystem

TPS: treatment planning system

ACS: accelerator control system

The dosimetry cycle is defined as the set of sequential operations that are triggered cyclically by the timing system and sequence the collection, display and monitoring of data.

Interlocks: All prerequisite, steady state conditions, not unique to a particular treatment, that must be met before an irradiation can begin must be interlocked. The following items must be interlocked:

· Personnel radiation safety circuits that restrict access to radiation areas.

· Dispatcher-enable signal that assigns the accelerator to the particular treatment room.

· Simulation status defining if the system is in simulation.

· Critical beam-line components as specified in [3.5.1, 4.1.3, 4.1.4, 4.2.4.4, 4.2.5].

· Critical power supplies whose malfunction can cause harm to a patient (e.g., scanner or gantry power supply ready).

· X ray beam simulator power and position.

· Critical detector parameters which if incorrect can cause harm to the patient (e.g., ionization chamber HV).

5-2 Beam Modification

5-2-1- Collimation: The identities and positions of collimators must be monitored.

For fixed patient collimators:

  • collimator(s) must be identified.
  • location must be monitored if adjustable.

For a variable collimator:

· the port size and shape must be controlled to a resolution determined by the hardware device.

· the control resolution must be greater than the physical resolution of the device.

· the mechanical method of defining the aperture must be appropriately monitored.

· times to create a port, including software control, must not exceed 1 second.

· the physical position (location and rotation) of the collimator must be monitored if adjustable.

For the movable radiation-shield collimator(s), the position(s) must be verified.

5-2-2- Range Shifting: For changing the proton range, by accelerator energy changes and/or by degraders, the energy range and step size must be controlled to satisfy the specifications [CS-2, CS-3, 2.1.3, 2.1.4]. The accuracy of the energy (beam range) due to software control must be better than 0.4 %.

5-2-3- Mechanical Range Compensation: Identification of the compensator must be verified.

5-2-4- Lateral Spreading of Radiation: The proton beam must be laterally spread out to produce the desired transverse dimensions, and appropriate parameters must be monitored.

For active devices, the following must be defined and controlled:

  • the target shape (e.g., a boundary/shape matrix of the port).

· a matrix for controlling beam motion and position.

· a beam current modulation matrix as a function of beam position

Passive (double, single, or bi-material scatterer) systems must be verified for correctness.

5-2-5- Range Modulation: Energy modulation, whether achieved electro­magnetically or mechanically, and whether discrete or continuously-variable, must be selectable by ITACS on an appropriate time scale. Monitoring must be performed of all critical parameters necessary to insure the beam energy is correct.

Accelerator energy changes require an established set of machine and beam transport parameters for each energy to be used. Monitoring must be performed of all critical parameters necessary to insure the beam energy and other beam properties are correct.

Ideally a mechanical device would automatically insert the correct filter, but installation by authorized personnel is also possible. In such a case, monitoring of the width of modulation must be performed.

5-2-6- Gantry/Patient Positioner: The gantry must be controlled for angular position with a resolution, range and accuracy as specified in [3.4.1]. The speed and the extent of rotation must also be controlled to prevent damage to the device or injury to the patient.

The control mechanism must be designed to insure rotation is not possible without proper authorization. Override of the computer control to allow manual control is required. Monitoring must be provided to insure the correct position is maintained at all times during an irradiation. Collision monitoring must be implemented to protect the patient and the equipment [3.5.6].

5-3-Measurements of Radiation Fields

5-3-1- Unmodified Beam Measurements: For a particular treatment, measurement of the beam before modification must be performed to insure proper beam conditions and for dose control.

The quantities that must be measured per system unit time are:

  • the beam current (or intensity), i.e., particles per unit time.

· the centroid position of the beam in two orthogonal planes at several locations along the beam axis.

The quantities that must be measured per dosimetry cycle are:

· the integrated beam current (particles per unit dosimetry cycle)

· the beam position in two orthogonal planes at two locations.

· the dose profile in two orthogonal planes at two locations. .

  • the integrated delivered dose at Isocenter.

The quantities that must be measured per treatment are:

· the delivered integrated dose at isocenter as measured by at least two independent, detectors.

· the beam range at the beginning of the treatment.

5-3-2- Modified Beam Measurements: Measurement of the beam after

modification for a particular treatment must be performed for dose control purposes and must insure the radiation field is properly shaped.

The quantities that must be measured per system unit time are:

  • beam position,

· dose as a function of position with a spatial resolution necessary to achieve the desired dose compliance.

The quantities that must be measured per dosimetry cycle are:

· the integrated, delivered dose at isocenter

· the integrated, transverse dose distribution with a spatial resolution necessary to verify the desired dose compliance.

The quantities that must be measured per treatment are:

· the integrated, delivered dose at isocenter and the integrated transverse dose distribution.

5-4- Software Beam Delivery Control

5-4-1- Low-Level Exposure Procedure: The Low Level Exposure procedure must provide the following dose control:

Minimum dose: 1 mGy

Maximum dose: 2 cGy (to prevent a therapeutic exposure)

Dose accuracy: ±10 %

5-4-2- Treatment Procedure: The Treatment procedure must provide the functions listed below to perform prescribed treatments.

· Dosimetry calibration information must be acquired from previously measured data or calculated from data-base information (of previous treatments).

· Patient setup parameters must be verified against the prescription. (Verification by medical personnel may be required.)

· Initial or previously used patient positioning parameters must be provided.

· Hardware parameters must be set to desired values.

  • The state of the interlocks must be verified.

· Patient positioning device settings during a treatment must be verified.

· The state of the procedure must be saved-on disk every dosimetry cycle to enable recovery in the event of an interruption caused by a computer failure.

· Halt and abort processes [5.12] must be provided.

· An abort of the beam must be executed upon treatment completion which occurs when all the steps of a procedure have been finished.

· An abort must occur upon the failure of acknowledgment of the watchdog [5.7.1].

· The treatment procedure must acknowledge the procedure-specific watchdog every dosimetry cycle within 100 msec.

· An interruption by personnel intervention, interlock dropout, critical hardware failure, a monitoring veto, watchdog acknowledgment failure, must be allowed. After such an interruption the state of the procedure necessary to resume a treatment must be preserved and the state of the treatment procedure restored for immediate resumption or saved under the identification of the patient for later resumption.

· Resumption of a treatment must be allowed, when after an interruption, the treatment procedure has not been exited.

· Resumption of a treatment must allow reentering the treatment procedure after either having previously exited it after an interruption or following a system crash.

· For an immediate resumption, the time to recover from an interruption must not exceed 10 seconds.

· The maximum dose uncertainty after recovery can not be greater than the dose delivered in a dosimetry cycle.

· Patient treatment data archiving and summary must be performed at the end of a treatment.

5-4-3- Calibration Procedure: The Calibration procedures must establish the conversion of the raw measured data to delivered dose at a specified location (e.g., at isocenter of a target or at a detector). The following calibration procedures must be provided.

· A Dosimeter Calibration for calibrating an individual dosimeter against a certified dosimeter to test a dosimeter's performance.

· A Dosimetry Calibration Procedure for calibrating the dosimetry system for creating the dosimetry calibration reference with a required precision of ±1%

· A Dosimetry System Reproducibility procedure for measuring the dosimetry system response for comparison against the previously created dosimetry calibration reference. The required precision is ±1%.

· A Patient calibration procedure for calibrating the dosimetry system response to a particular radiation treatment setup against a certified dosimeter placed at the isocenter of the target volume with a required precision of ±1%. A method for calculating calibrations from the accumulated data of patient treatments should be provided for future implementation.

5-4-4- Physics Applications Procedures: Applications procedures must be provided for characterizing the beam and radiation field properties. The applications procedures must permit measurements for:

  • an entire treatment irradiation,
  • an unmodified beam irradiation,

· irradiations involving a subset of an entire treatment parameter set

· a measurement sequence of specific, individual steps of an irradiation.

5-4-4-1- Options for Physics Applications Procedures: Additional features that must be included in this application(s) are:

· the ability to enable or disable specific beam monitoring .

  • the ability to set beam modification devices (e.g., range shifter, range

modulators, gantry angles,)

· the ability to interrupt a measurement and resume it without loss of data

· the ability to connect additional devices through I/O ports

5-4-5- Diagnostics and Tools: Diagnostics must be provided for verifying the proper workings of the system along with software tools for troubleshooting. These aids must be executable continuously or upon demand and must have restricted access.

5-5-Hardware Beam Delivery Control

Hardware beam delivery control of an irradiation must comprise the functions necessary for starting, stopping and controlling an irradiation.

5-5-1-Starting an Irradiation: Starting an irradiation must involve enabling and initiating actions. The conditions for enabling an irradiation must include:

  • all interlocks satisfied,
  • all watchdogs acknowledged,
  • all monitoring vetoes absent.

Initiating an irradiation must include:

· receiving authorization from a qualified operator,

· controlling the beam abort/halt system.

5-5-2- Controlling an irradiation: For controlling an irradiation, the delivered dose must be tracked and the beam modification devices properly controlled. Computer-read scalers and preset scalers must track the delivered dose for beam control. Device Controllers must provide:

· computer and manual control of the device operation,

  • status on the device operation

· full closed loop control of the device whenever feasible.

5-5-3- Stopping and restarting an irradiation: Stopping an irradiation requires a halt and an abort action. See [5.12].

The conditions which can cause halting an irradiation must include:

  • a personnel initiated halt of the treatment
  • a software commanded interruption
  • a computer-loaded, preset scaler firing
  • a command from critical device controllers (e.g. gantry position).

Continuation of the irradiation must be synchronized with the accelerator upon release of the halt command. The contribution of a halt to the irradiation dose error must be less than ±l % in any region. The conditions for aborting an irradiation must include:

  • any interlock broken
  • a failure of any watchdog acknowledgment
  • any hardware or software monitoring veto
  • a personnel initiated abort of the treatment

· any computer or manually-loaded preset scaler triggering.

An abort must preclude an immediate continuation of a treatment.

5-6-Human Interface

The human interface must provide the medical and operations personnel with graphics and alphanumeric displays, development / diagnostic tools, visual hardware-status displays, error notification and alarms.

5-6-1-Console Displays: Appropriate console displays must be provided to facilitate the operator interaction with the control system. The graphics and alphanumeric displays which provide visibility into specific system operations must meet the following requirements:

· the refresh rate of the display be at least once per dosimetry cycle,

· include a software acknowledgment of the display procedure watchdog.

The following displays are required at treatment control consoles, the setup rooms, the treatment rooms, and/ or accelerator control room:

5-6-1-1-Pre-Treatment Information Display: The pre-treatment information display must provide prescription information for a treatment to allow setup of the patient.

5-6-1-2-Irradiation Information Display: The Irradiation information display must provide information of a treatment in progress and must be tightly coupled with the irradiation procedure to insure that the current state of the irradiation is being presented.

5-6-1-3-Irradiation Summary Display: The Irradiation summary display must provide the results and summary of a single irradiation.

5-6-1-4-Patient treatment summary display: The Patient treatment summary display must present a summary of all treatments for a specified patient/ time 'period obtained from the archiving.

5-6-1-5-Facility status / scheduling display: The Facility status/scheduling display must provide the current status of patient treatments and accelerator operations for medical personnel at appropriate locations.

5-6-1-6-Beam delivery display: The Beam delivery display must provide information on the condition of the beam delivery system for a given treatment room for ascertaining its proper functioning by the operations and medical personnel.

1-6-1-7-Measurement data display: The Measurement data display must show a specified set of data, measured by user-specified detectors in a specified form (numerical or graphical) for a particular irradiation. Provision must be made for displaying Bragg curves and dose distributions.

5-6-1-8-Development/Diagnostic Tools: The Development/Diagnostic Tools must contain the displays specified above which must be capable of running concurrently. Spigots for analysis of critical signals must also be provided.

5-6-1-9-Visual Hardware Status: A direct visual hardware presentation must be provided to operations personnel to determine whether the system is in proper, working condition.

5-6-1-10-Error Notification: A means of notifying operations personnel of error conditions must be provided along with a system of permanently archiving them.

5-6-1-11-Alarms: Alarms (that will be defined at the time of a design) must have a visual and an auditory component.

 

5-7-Monitoring

 

5-7-1- Watchdogs: The watchdog function is a hardware-driven periodic monitoring of critical software operation. The hardware components of the watchdogs must arm themselves when triggered by timing signals. The software components of the watchdogs must acknowledge the hardware modules within the required time. A handshake must occur between the software and hardware components to complete the acknowledgment. Upon failure of a watchdog function an abort of the beam must be performed. A watchdog cycle must take place over one complete cycle of the-process being monitored and must be acknowledged by software in a time not greater than 100 msec.

5-7-2- General monitoring: In general monitoring, limits (windows), boundaries (extrema) or values (specific quantities) defined either by software or hardware must be compared against an actual state or value and a determination made as to whether or not to assert a veto.

5-7-3- Beam Modification Devices: All critical beam modifying devices must be monitored.

5-7-4- Monitoring of Accelerator: Critical accelerator parameters must be monitored separately from any verification performed for accelerator control purposes. Monitoring must be performed at least every accelerator cycle, but preferable continuously during beam extraction.

The following accelerator parameters must be monitored:

· beam time structure (length, presence of spikes, absences of holes)

  • beam energy or rigidity [2.1.3, 3.3.3]
  • beam alignment at the exit of machine [2.3.2]

· beam profile in two orthogonal directions at the exit of machine

  • beam current at the exit of machine

· accelerator parameters defining the desired accelerator state

5-7-5- Monitoring of Radiation Properties: Radiation properties before and after beam modifying devices must be monitored. The radiation properties before beam modifying devices that must be monitored include:

.

· beam range or quantity from which the range can be inferred.

.

  • beam current at least every dosimetry cycle

.

· beam position and alignment at least every dosimetry cycle

.

  • beam profile in two orthogonal directions

The radiation properties after beam modification occurs that must be monitored include:

  • beam range
  • field alignment at least every dosimetry cycle

· delivered dose at specified locations at least every dosimetry cycle

· field compliance at least every dosimetry cycle

5-7-6-Monitoring of Beam Transport System: The beam transport system must be monitored at the beam switchyard and before the first beam modification device [3.2.2]. In addition the beam abort/halt system must be monitored. The following parameters should be monitored:

  • Beam alignment
  • Beam shape
  • Beam current
  • Beam line choice (i., e., which treatment room)
  • Beam line magnetic fields
  • Beam line magnet currents

 

5-8- Simulation

A method must be provided for testing the integrated accelerator and treatment control system without the use of beam, that is capable of generating measurement information and subsystem status. Individual treatment control system and accelerator control system simulation must be provided.

 

5-8-1- Simulation Interlocking: This capability must be interlocked to prevent erroneous use and must be carried out to the lowest level possible.

5-8-2-Simulation Control: Independent simulation of selected accelerator and treatment control systems must be provided.

5-8-3- Simulation Information: The simulation procedures must provide:

· measurement data,

· beam-modification device control and status information,

· accelerator parameter values and responses,

· accelerator/treatment control subsystem link information (of each for the other when de-coupled from accelerator).

· beam abort/halt control and status information,

· beam-stop and beam transport status,

· timing signals which will mimic real accelerator timing, permit dosimetry cycles twice that of the accelerator cycle and allow software-programmable timing signals.

· monitoring status of the accelerator subsystems and treatment control subsystems

Simulation of monitoring must include the capability of suppressing monitor vetoes. Such suppression must be interlocked and disabled when leaving the simulation mode.

5-9- Accelerator Interface

5-9-1- Software Communication Switch: The accelerator interface of a particular treatment control subsystem must provide a software switch for granting exclusive use of the accelerator to that particular treatment control subsystem. At the same time the dispatching function must set a software switch in the accelerator control subsystem allocating the accelerator to that treatment room only.

The following information must be provided by the accelerator control subsystem to the treatment control subsystem software via the accelerator interface every accelerator cycle:

· the beam energy, rigidity, current (intensity), position, shape

  • the accelerator magnetic field and RF
  • the necessary beam transport data (e.g., beam transmission, position, shape)

The desired energy and intensity must be provided by the treatment control subsystem to the accelerator control subsystem via the accelerator interface every accelerator cycle.

5-9-2-Hardware Communication: The treatment room selection made by the dispatching function must result in setting a hardware switch in the accelerator interface and a hardware switch in the accelerator control subsystem allowing only hardware signals from the chosen treatment room to go between that treatment room and the accelerator. The hardware signals that must be sent to the treatment control subsystem via the accelerator interface are: the beam extraction status, the beam abort/halt status, and the beam-stop status.

5-9-3- Simulation: The accelerator interface must be capable of simulating all necessary data and status information for the accelerator and the treatment control system to allow independent (operation of one from the other. See [Sec. 5.8].

5-10- Accelerator Control

The accelerator control subsystem must control the accelerator hardware and safely provide the desired beam characteristics for an irradiation. The accelerator control subsystem must operate the following components:

  • an ion generator,

· the injection system for initial acceleration and transport of ions into the synchrotron,

· a synchrotron for accelerating the ions to the desired energy,

· an extraction system for removing the beam from the synchrotron,

· a beam transport system for channeling the ions to the desired treatment room,

· a sequencing and timing system for control of the beam,

· a monitoring system for insuring correct and safe operation,

· a system for saving and restoring the parameters of the accelerator control subsystem.

The performance of each of these subsystems must be monitored and a software check performed to insure the subsystem is functioning (alive-and-well check). The subsystem parameters that are set (set-points) must be verified.

5-10-1-Measurements of Beam and Device Parameters:

Measurements of beam properties and device parameters must be provided for control, status, and monitoring. Monitoring must be performed independently from control and status measurements. Critical measurements must be traceable to fundamental standards with well-specified calibration procedures and frequency of calibration.

5-10-2- Communication Links: Several types of links must exist between the accelerator and beam delivery subsystems and their components. (The communication link between the ACS and TCS are described in the [5.9] Accelerator Interface, [5.12] Abort/Halt, and [5.13] Dispatcher sections.) Communication links between the various accelerator control functions and their corresponding components must be performed using active messaging and not common memory.

5-10-3-Control Structures: The accelerator 'control function components must be clearly defined (e.g., actuators, sensors, control parameters), along with their relationships. The set-points (values), set-point tolerances (windows) and achievable boundaries (extrema) must be incorporated into the control system.

5-10-4- Simulation: Simulation must be provided to mimic measurement information and status to allow testing of the TCS and ACS without actual beam acceleration or magnets operation.

1-10-5- Save/Restore: A system must be provided for saving and restoring the parameters of the accelerator control system (e.g., machine tune) in part or all in all.

5-10-6- Archiving: Archiving must be performed to allow reconstruction of the state of the system. Archived data will be used advantageously for trouble shooting and diagnosis. See [5.15].

5-10-7- Alarms and Monitors: Critical parameters of the accelerator must be monitored. Alarms based on parameter values being outside defined limits must be provided.

5-10-8- Keep-Alive: A clear handshaking or wrap around exchange protocol must exist between coupled functions to insure they are properly functioning.

5-10-9- Critical features for accelerator operation: Design guidelines listed below must be implemented.

· measure beam rigidity and emittance near the exit of accelerator,

  • guarantee the beam shape and alignment(e.g., by using baffles),
  • permit high level orbit corrections,

· provide energy control accuracy specified in [2.1.3],

  • provide self-diagnosis algorithms

 

5-11- Timing

5-11-1- ACS Timing: The sequencing and timing for the various, accelerator-control functions must be provided.

5-12- Beam Abort/Halt

A means of stopping the beam upon request must be provided. Its design must be fail-safe and have a halt and an abort mode of operation. Status on its state must be provided at all times.

5-12-1- Halt: A halt must turn-off the beam. The response time of this system must be such that the dose can be controlled to an accuracy of 0.1% in any region of the tumor volume. The end of a halt must be synchronized with the accelerator and dosimetry cycle. Buttons for beam halt at the treatment control station must be provided. The following conditions must cause a halt:

  • an action by a qualified person (e.g. ,pushing a halt button),

· completion of a step in an irradiation procedure,

· the monitoring system's detection of anomalies potentially hazardous to the patient (e.g., motion of patient couch)

5-12-2- Abort: The abort process must turn off the beam by halting the beam and inserting a beam-stop. This action must not allow an immediate continuation. The following must cause halts:

  • an action by a qualified person (e.g., pushing an abort button, opening a radiation door),
  • completion of an irradiation procedure,
  • loss of any interlock,

· the monitoring system's detection of anomalies potentially hazardous to the patient (e.g., unwanted gantry rotation).

5-13- Dispatching

5-13-1- Dispatching: A method for connecting the accelerator to a treatment room must be provided. A method for handling requests from more than one treatment room must be included.

This dispatching function must:

· receive simulation and radiation interlock status

· assess the availability of accelerator and beam transport systems

  • receive requests from all treatment rooms

· allocate the accelerator only upon a request from a treatment room

· select a treatment room to connect to the accelerator based on an algorithm (This algorithm could initially be as simple as "first come first serve.")

· set a hardware switch in the ACS for exclusive use of the accelerator by a treatment room

· set a hardware switch in the selected treatment room to allow communication with the accelerator (Hardware signals from only that treatment room may then go to the accelerator.)

· set a software switch in the ACS that allocates exclusive use of the accelerator to the selected treatment room

· set a software switch in the accelerator interface that grants exclusive use of the accelerator to the selected treatment room (Software signals from only that treatment room may then go to the accelerator.)

· provide hardware and software handshakes between the dispatcher, the treatment room and the accelerator. In simulation mode handshakes must be mimicked.

5-14- Prescription Server

5-14-1-Prescription Server: A function must be provided for connecting the treatment planning system with the treatment control system for the exchange of all necessary information.

This prescription server must be provided for transferring and storing the parameter sets determined from the TPS to the TCS for each patient treatment. The information exchanged between the TPS and TCS must be properly presented (in the right format) for use by the other. Results of each treatment delivered by the TCS must be available for feedback into the TPS for refinement of the treatment plan.

5-14-2- Security: Protection from unauthorized/inadvertent modification of treatment parameters must be guaranteed. A means of independent verification of patient-specific, treatment parameters before a treatment must also be provided.

 

5-15- Archiving :

An archive of the history of beam delivery for the entire facility must be provided. Archiving must include both raw and processed data records of the ACS and TCS for the following functions:

  • Treatment Summary
  • Treatment Reconstruction

· System Recovery

· Data Base Functions

5-15-1-Treatment Summary: Treatment summaries must be provided at the end of a treatment and at the end of each treatment period. Data records of the following must be kept:

· each treatment summary for a patient

· the summary of all treatments for a patient

· the delivered dose matrix for each treatment

5-15-2-Event Reconstruction: Critical raw and processed data records must be kept permanently for each dosimetry and accelerator cycle.

5-15-3- System Recovery: Sufficient data must be archived to allow treatment

control subsystem recovery and treatment resumption at any later time. (Recovery time is specified in the treatment procedure specifications.) Data sufficient to resume irradiation operation at any later time must be saved.

5-15-4-Legal Requirements: All clinical information necessary to satisfy medical and legal requirements must be archived. This must include:

· patient identification

· tumor dose for both an individual treatment and accumulative treatments,

· dose to critical organs for both individual treatment and accumulative treatments,

· personnel involved in treatment.

 

5-15-5- Security: Protection from unauthorized/inadvertent modification of treatment parameters is required.

5-15-6- Data Base Functions: Archived data must be available for creation and refinement of parameter look-up tables for the ACS and TCS. Provisions must be provided for recovering data from specification of a single parameter or combination of parameters from a pre-defined list or on any pre-defined labeling of the system parameters.

5- Treatment Ancillary Facilities

6-1- Pre-Treatment Equipment such as Diagnostic Tools

6-1-1- Patient accrual: A computer facility must be provided by a tool which is networked to nationwide protocol control, picture archiving and computer systems, therapy planning computers, and treatment control computers.

6-1-2-Diagnostic Equipment: The diagnostic imaging equipment must be provided to furnish following capabilities:

· ability to obtain image data from CT, MRI, SPECT(single-photon emission computed tomography), Angiogram, and Gamma camera through PACS (picture archiving and computer system) network systems for acquisition by the treatment planning computer

· the use of a flat table top insert for CT and MRI

· the ability to incorporate all the immobilization devices which will be used for treatment

· long-term storage capability of image data from all imaging devices, such as CT or MRI, must be provided by optical disks in the Radiology Department, otherwise an optical drive must be provided in the treatment planning area.

6-2- Treatment Planning Software and Hardware

6-2-1- Treatment Planning : The therapy planning system must provide following capabilities:

1. dose calculation for non-coplanar beams

2. 3-dimensional dose calculations incorporating multiple scattering

3. modeling the beam delivery system

4. designing 3-dimensibnal"smeared" compensators

5. computing "worst-case" dose distributions

6. specifying the resolution of the calculation

7. specifying the resolution of the calculation

8. dose-volume histogram calculations

9. user friendly quality of the system

10. various dose display options

6-2-2- Requirements for image-manipulation for the therapy planning code:

Following image manipulation capabilities are required for the therapy planning system:

1. editing CT numbers

2. Window and Leveling capabilities

3. image magnification options

4. contouring modes

5. digitally-reconstructed radiographs (DRRs)

6. projecting contoured structures on DRRs

7. the collimator design options

8. image correlation of CT images with other images

9. beam's-eye-view alignment aids

6-3- Patient Positioning and Alignment Devices

6-3-1-Immobilization material in the beam: The immobilization material placed in the beam must be < 5 mm water-equivalent.

6-3-2- The immobilization devices must not cause artifacts in the CT or distortions in the MRI: No ferromagnetic materials must be used in the immobilization for MRI imaging. No metal may-be present in the immobilization for CT imaging, except for small fiducial markers, pieces 2 mm3 or less in volume. The immobilization must not attenuate the x-ray beam so much that the quality of the images obtained is compromised.

6-3-3-Ease of immobilization and releasing of the patient: The immobilization must allow the patient to be put in place and removed quickly, easily, and safely. The patient must be completely freed from immobilization within 30 seconds from the time of distress.

6-3-4-Immobilization for non-ambulatory patients: For non-ambulatory patients in the case of a building emergency it must be possible for the technologists to remove the entire immobilization assembly with chair or couch from the patient positioner, placing it on a dolly, and roll it out of the treatment room to a safe place.

6-3-5-Immobilization and patient emergency: Immediate access (< 30 seconds) must be provided for the technologists to attend the patient in case of emergencies.

6-3-6- Patient alignment accuracy: The tolerance in patient misalignment is specified in this Section.

6-3-6-1-Margins of error: The allowed margins of error for the different regions of the body are specified in the list below.

The translation and rotation requirements are summarized in the table below:

6-3-6-2- Control of body flexure: The immobilization must prevent the flexing of the body as described below:

Rotation limits of temporomandibular joints: <1 degree.

Bending of the spinal column per 10 cm of length <1degree

6-3-7- Patient couch: Specifications for patient couch are given in this section.

6-3-7-1- Range of motion of the couch in gantry room: The couch which will hold the patient in horizontal position (e.g., supine, prone, or decubitus) for gantry treatment room must be specially designed to satisfy listed specifications.

  • Couch motion ranges:
  • Lateral motion ± 30 cm from table center
  • Along the body axis: > 120 cm

· Vertical motion: from the beam center to 30 cm above the floor.

· Table rotation around the vertical axis: ±95 degree

· Table rotation around the horizontal axes: ±5 degrees

  • Flexing under weight: <1 mm

· Absolute table position accuracy: ±1mm and ±1 degree

  • Relative table position accuracy: ± 0.5 mm and ±0.2 degree .

6-3-7-2-Couch motion control: Automatic and manual control methods of the couch motion must be provided according to the specifications listed below. The paramount importance here is the patient safety.

· The control computer must monitor couch position all the time.

· The speed of the couch motion must be variable from 1 mm/ sec to 10 cm/ sec so that the requirements of precise, small movements and large repositioning between ports, can both be accomplished with the required accuracy and with minimum lost time.

· Collision protection: The couch must have collision detectors to protect the patient in the event of an incorrect positioning command. There must be fixed detectors at the corners of the couch and at least two detectors on wires which can be fastened anywhere to the couch or immobilization. Tripping any detector must stop all motion in the room, including the couch, gantry, and everything on the gantry. A reset procedure must be provided to allow the correction of the unsafe situation and the continuation of operations.

· Automatic operation for patient treatment: All computer commands must receive permission from a person in the treatment room before they can be carried out (except for the case of dynamic treatment mode as explained below); this may be accomplished through a request displayed on a terminal in the treatment room and with a affirmative response or by a permit switch at the couch. In non-patient mode (i.e., any irradiation in which no patient is present), this requirement is not needed.

· Manual operation: The manual controls must include a "Dead-man" switch configuration and a "Stop" button that overrides a computer command and instantly (in 0.1 second) stops all couch motion. These controls and a position readout must be operable by a person standing at the couch itself.

· Crash off: There must be sufficient "couch and gantry power crash off" buttons placed in the room so that so that a button can be reached in 5 seconds from anywhere in the treatment room.

6-3-7-3- Couch movement for dynamic treatment: The two horizontal translations must be available for use during treatment in the event that very large field sizes are needed. Couch speed would be 2 cm/ sec or less in this mode.

6-3-7-4-Patient couch/chair for fixed-beam room: For treatment in the horizontal fixed-beam room, it is expected that patients will need to be positioned in a chair in addition to a couch. For this purpose, there must be either a chair attachment to a couch, or a stand-alone chair. Either way, the chair must have all the motions required for the couch above, namely, 3 translations and 3 rotations.

· The horizontal translations must allow excursions of ±30 cm about the body center and motion along the patient axis (height change above floor) must be adequate to allow treatment from near the top of the head to the top of the pelvis. This requires 120 cm of vertical motion. To accomplish treatment to the head requires a beam height above the floor of at least 150em.

· Provision of at least ±l0 degree pitch and roll is required since the beam is fixed and larger variations of ± 20 degrees would be even better to accommodate the desire to bring the beam in to the patient at a slight oblique angle. Full rotation of ±185 degrees about the vertical axis is required in order to use any beam angle in the axial plane.

· All controls of the motion of the chair must be the same as for the couch, except that for dynamic mode it is the vertical and the horizontal motion perpendicular to the beam direction which must be available for movement during treatment.

· The speeds of the chair motions must be the same as the couch speed described above.

· The accuracy and precision required is the same for the chair and the couch.

· Collision detectors will also be needed as described above.

6-3-8- Patient Alignment: The process and requirements for the precision alignment of the patient to the collimator, compensator, and proton beam line are described in this section.

6-3-8-1- Coordinate System: All positions and movements must ultimately be stated in terms of the room coordinate system described below.

In each treatment room there will be a coordinate system with its origin at a point along the beam axis, at the center of a gantry's circle of rotation or of a couch rotation for a horizontal beam line. This point is called isocenter. For both rooms the first axis is vertical. The second is horizontal in the plane of gantry rotation (or perpendicular to the beam line in the horizontal beam line room). The third is perpendicular to the plane of gantry rotation (or along the beam line in the horizontal room). The directions of the axes must be so as to form a right handed

coordinate system.

6-3-8-2-The Alignment Process: The process of aligning the patient is described below.

The process of alignment will first make use of lasers for the rough alignment of external anatomy or marks on the immobilization to laser lines marking the three axes of the coordinate system. But final alignment is performed with x rays imaging internal anatomy. These images are compared with images from the. treatment planning showing the desired relation of the .collimator, compensator, and isocenter to internal anatomy. Then the positioner will move the patient to the correct position. .

 

6-3-8-3-Equipment for Alignment: The equipment needed for alignment and the manner of use are described below.

Both areas must have the following equipment:

1) A set of orthogonal lasers which have a reproducible accuracy of ± 0.5 mm at isocenter. They must comply with the Center for Devices and Radiological Health regulations for Class II lasers. The laser lines must be clearly visible in normal bright room light.

2) X-ray tubes to give standard orthogonal views of patient anatomy (i.e., AP and lateral) and beam's eye view for all directions in which that's possible. If possible they must have the same SAD (source to axis distance) as the effective SAD of the proton beam. The x-ray sources must be able to be positioned on the room axes to an accuracy of .5 mm. The tube which will give the beam's eye view must be positionable to within .5 degrees of the particle beam direction.

3) An x-ray detection system. Although the initial detection system is likely to be film, there must be the capability for a digital imaging system. If an adequate digital system is available at the time the room is built, then that is what must be installed. The detection system must have a spatial resolution to give a pixel size of .5 mm or less for a plane through isocenter.

Furthermore, the imaging system as a whole (sources plus detectors) must be efficient enough so that all the needed images at one patient position (frequently 2 orthogonal views) may be taken within 10 seconds. This may be accomplished by using many sources and detectors or by rapid repositioning of the hardware items. The system must not interfere with treatment and must comply with all applicable safety codes. The system must display the positions of isocenter (i.e., cross-hairs) in all views and the field edge (collimator shape as projected onto the plane through isocenter) in the beam's eye view on top of the patient's anatomy. All images must have the same magnification and divergence.

A digital imaging system must work in conjunction with the treatment planning system. There must be the capability of displaying the digital, possibly enhanced, images on monitors throughout the department within 10 seconds after capture. There must be the ability to display images from the treatment planning system on top of the digital setup image and for a person to manipulate one of the images in order to determine any movement needed to put the patient in the correct place. The system must then calculate the needed move, and after receiving permission from the technologist in the treatment room perform the actual move.

6-3-9- Patient position verification: Verification of the patient target relative to the beam requires the use of isocentric lasers, isocentric diagnostic x-ray tubes and radiographic detectors.

6-5-2- Intercoms in treatment console areas: There must be a minimum of two communication methods:

1. one is intercom between the console area and the patient in the treatment room, and

2. another between the console area and the accelerator console area and/or the entire facility.

6-5-3- Record and Verification:

Treatment parameters such as couch coordinates, gantry angle, collimator opening and orientation, the use of compensator, Cerrobend or brass beam shaping device, beam type, beam energy, or any relevant information must be stored in a centralized area for comparison with the parameters obtained from the treatment planning and/or simulations.

These parameters will be compared with those obtained from treatment planning, and when they are compatible the computer give its OK for treatment start.

6-6- Machine Operation Modes

6-6-1-Patient Monitoring: There must be at least four different operation modes available for the proton medical facility:

1. Morning check out mode

2. Treatment Mode

3. Physics Mode

4. Special Mode

These minimum four modes must be easily programmable for radiation therapists:

1. Morning check out mode -This mode allows radiation therapists or operators to gather and check all the necessary accelerator parameters that would be required by the accelerator engineers to solve problems if the accelerator or its accessories malfunction. This mode must include the morning warm-up procedures that are deemed necessary

2. Treatment Mode -actual treatments by radiation therapists to treat the patients. This mode is operable only if all of the patient information and patient treatment setup files are complete; at the end of the procedure a patient treatment record is produced.

3. Physics Mode -same as Treatment mode except it permits irradiations without any patient.

4. Special Mode -Allow the technical staff to operate the facility bypassing certain interlocks for the purpose of debugging or measurements, for example.

 

6-7- Safety Requirements

The safety of the entire system is of paramount importance. While safety is difficult to specify, a safe system will include redundant guards against any conceivable failure mode. Specific attention must be given to beam delivered outside the chosen target area, incorrect dose rate, incorrect total dose, collisions of patient with nozzle components, avoidable exposure to facility workers, and accidents involving fire, electrical or vacuum systems. Control system hardware and software must pass strict safety and quality assurance tests. The entire facility will be required to meet relevant federal and state safety standards for patient treatment devices. Control systems and all patient-related hardware must be designed to be "fail-safe", that is, the consequences of

a failure cannot compromise the safety of the patient or the facility.

6-7-1- Patient Monitoring:

There shall be a minimum of two pairs of cctv camera and CRT screen operable for continuing viewing of the patient during treatment. This continuous patient monitoring devices must have focus, iris adjust and zoom capability. A combination of two cctv cameras are located in such a way that the entire treatment room must be observable from the treatment console area.

There shall be a minimum of one intercom between the treatment console area and the treatment room operable for verbal communication between the patient and radiation therapists and/or radiation oncologists during treatment. The communication through Intercom must be clearly audible to every party involved in the communication.

6-7-2-Emergency Buttons:

There will be a three level of power off emergency buttons. They must be clearly marked and must be distinguishable from each other both in shapes and colors.

1. cut off the power to the entire facility (level one emergency)

2. cut off the power to the room and equipment a person is working (level two emergency). The beam must not leave the accelerator or be diverted to the beam dump within 10 µ sec after this button is pushed. The room light must not go out in this mode.

3. divert or turn off the beam within 10 µ sec to the beam dump after the button is pushed(level three emergency).

There shall be a minimum of one level two emergency button in each of treatment console area, where radiation therapists are located during treatment.

There shall be at least one level two emergency button located on each side of a patient treatment couch and at least two more at the strategic locations in the treatment room; for example, on the wall opposite of the treatment couch. All emergency buttons shall be located at the clearly visible locations. They shall be protected from the accidental activation of the buttons.

The accelerator control console must be equipped with one Level one and one level three buttons. Any radiation hazard areas must be equipped with o.ne level three emergency button. These area include beam switch yard and beam transport area.

6-7-3- Door Interlocks:

There shall be at least two electronics switches located on the door or door jamb. These switches shall function as the level three emergency button and thus stops the radiation exposure within 10 µ sec when the door was opened by more than 3 inches. Closing of door shall not cause the radiatio.nto.be resumed. The radiation shall resume only when door is closed and the operator initiates the exposure, assuming that all the other interlocks are properly set.

6-7-4- Radiation Monitor:

A red and white light shall be located above the treatment room door. The white light shall be turned on whenever the accelerator power is turned on without the beam in the accelerator and beam lines. The red light at the entrance of each treatment room shall be flashing during the delivery of the beam to that treatment room.

The control console shall be equipped with an indicator indicating that the accelerator's main power is on. It shall also be equipped with an indicator indicating that the beam is being delivered to that room and that high radiation exposure exists during the beam-on mode.

There shall exist a communication mechanism between the accelerator operators and radiation therapists for delivery and instantaneous ceasing of the beam; for example, electronics communication using CRT screen and a backup mechanism (such as intercom) in case the former fails to function.

There must be an alarm system which must sound "alarm" and initiate red light flashing should anyone of radiation monitors placed in strategic places read more than the limits set by the State of California, by the local authorities, by the UCD Medical Center or any other authorities who have jurisdiction over the propose Proton Treatment Facility. The alarm system must simultaneously trigger either to divert the beam or shut off the power to an accelerator so that the radiation readings in the entire facility accessible to all personnel in the facility including patients and visitors must instantly become less than the limits set by the above mentioned authorities. Neutron levels at 1 m from the isocenter must be less than 0.1 % of the dose at the isocenter.

 

6-7-5- Mechanical Safety:

Patient couch, gantry and any other treatment aids in contact with or adjacent to the patient shall be locked or "frozen" as soon as the power is cut off either by activating one of the emergency buttons, power failure or intentional power shut­off.

There shall be a collision interlock mechanism whereby the power shall be cut off upon the contact of the patient couch with a gantry and any other patient treatment aid devices.

 

REFERENCES

· W. Chu et. al., Performance specifications for proton medical facility, LBL -33749, UC00, 1993.

This document is the most important in this field. It was prepared by 13 experts from the most famous labs and centers in this field (LB Lab, Loma Linda and California University) upon the request of NHI of the USA to put the specifications of the proton facility therapy for the 21st century.

E. B. Prodgorsak, Radiation oncology physics: A handbook for teachers and students, IAEA, Vienna, 2005.

This publication is aimed at students and teachers involved in programmes that trains professionals for work in radiation oncology.it provides a comprehensive overview of the basic medical physics knowledge required in the form of syllabus for modern radiation oncology. It will be particularly useful for graduate students and residents in the in medical physics programmes, to residents in radiation oncology as well as to students in dosimetry and radiotherapy technology programmes. It will assist those preparing for their professional certifications in radiation oncology, medical physics, dosimetry or radiotherapy technology. It has been endorsed by several international and national organizations and the material presented has already been used to define the level of knowledge expected of medical physics worldwide.

Cyclotron Produced Radionuclides: Principles and Practice

Technical Reports Series No. 465, IAEA, 2008, ISBN 978–92–0–100208–2ISSN 0074–1914.

 

This book provides a comprehensive treatment of cyclotrons, with a special emphasis on production of radionuclides. Individual sections are devoted to accelerator technology, theoretical aspects of nuclear reactions, the technology behind targetry, techniques for preparation of targets, irradiation of targets under high beam currents, target processing and target recovery. This book will appeal to scientists and technologists interested in translating cyclotron technology into practice, as well as postgraduate students in this field

Egido Mauro, Radiation protection studies for CERN linac4/SPL accelerator complex, 2009, Lauzanne, Switzerland.

This doctoral dissertation conducted detailed studies on the CERN linac4/SPL complex, covering the following topics: radiation protection, proton accelerators, induced radioactivity, shielding design, FLUKA code.

Roelf Slopema, Basic Physics of Proton therapy, University of Florida, Proton Therapy Institute, 2011.

This document covers extensively the basic physics of proton therapy including Basic Interactions and Clinical Beams: Energy loss, scattering and nuclear interactions, lateral penumbra, excitation and ionization of atoms, loss per interaction, range secondary, stopping power, Bragg peak, nuclear interactions, skin dose, distal fall-off, proton vs. photon, integral dose, range compensator, aperture, clinical penumbra, air gap and penumbra and scanning penumbra.

E. M. Syresin, Centers of hadron therapy on the basis of cyclotron, joint institute for nuclear research, Dubna, Russia, 2008.

This document covers the following topics: JINR medical technical complex, requirement to medical proton beams, cyclotron centers of proton therapy, Dubna cyclotron center of proton therapy, formation of carbon radioactive primary beams.

Zuofeng lee, Proton therapy physics and techniques, Proton therapy institute, University of Florida, 2011.

This document covers comprehensively the physics and techniques of proton therapy with concentration on application techniques. Essentially, the following titles are covered: physical characteristics of charged particles beams, charged particles interactions, RBE of photons, carbon ions and proton delivery techniques.

E. B. Podgorsak, Treatment machines for external beam radiotherapy, McGill University, Montreal, Canada, 2007.

This lectures material consisting of 126 is slides based on chapter 5 of "Radiation Oncology Physics" book, IAEA, and its objective is: to familiarize students with basic principle of equipment used for external beam radiotherapy and all related considerations.

Richard P. Walker, the diamond light source: the synchrotron light source, Diamond, UK, 2009.

This document explains in details the biggest scientific investment in the history of UK. This synchrotron center produces a light with billions times the intensity of the sun light reaching the earth. This light has many applications in different fields of science.

C. R. Prior, The physics of accelerators, trinity college, Oxford, UK, 2009.

This document covers the physics of accelerators including: basic concepts in the study of particles accelerators, methods of accelerations linacs and rings), controlling the beam (confinement, acceleration, focusing), electrons and protons (synchrotron radiation, luminacity).

 

Related Articles and reports

1 – V. A. Anferov, et al, Indiana University cyclotron operation for proton therapy facility, Cyclotrons and their applications, 8 Int. Conf., pp. 231-233, 2007.

2- J. Kim, Proton therapy facility project in National Cancer Center, Korea, Journal of Korean Physical Society, Vol. 43, pp. 54-54, 2003.

3 – K. Noda, Status of particle therapy in Japan, Journal of Korean Physical Society, Vol. 59, No.2, pp.528-538, 2011.

4 – C. C. Kao, Synchrotron light sources: Review and perspectives, 15th International Conference on accelerator and beam applications, Gyeongiju, Korea, September, 29-30, 2011.

5 – M. Umezawa, Hitachi proton beam therapy system, Particle Beam Therapy Symposium, AAPM 55th meeting, 2013.

6 – A. Smith and H. Paganetti, Proton therapy, AAPM 50th annual meeting, 2008.

7- H. Pagnetti and T. Bortfeld, proton beam therapy: the state of the art, Springer Verlag Heidelberg, ISBN-3-540-00321-5, (36 pages), 2005.

8– Y. Kumata, Current status of proton therapy in Japan #2, the Japan-Russia cooperation seminar, Moscow, 2013.

9- Data collected from tens of proton related websites and used appropriately.