01 Introduction to the transition to 3D HDR brachytherapy · 2018. 9. 27. · Brachytherapy: a...

IAEA

3D HDR brachytherapy equipment selection,

acceptance testing procedures, commissioning

andquality assurance -

quality control

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Aims

Assuring accurate and safe delivery of radiotherapy to cancer patients through setting up a quality assurance/review system.

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Specific Learning Objectives

• General Terms of QC and QA in cancer management• To define specification, acceptance, commissioning and

quality control (QC) as it applies to brachytherapy• To describe the procurement process including specification

and acceptance• To describe the commissioning process• To describe the components of quality control tests

Quality - definition: Degree or standard of excellence

The totality of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs.

Not to be mistaken for "degree of excellence" or "fitness for use" which meet only part of the definition.

Quality is dependent on:

Education, trainingStudents -recognisedtraining and education courses (academic and clinicalcomponents)Build knowledge, develop skills and competencies

On the jobSupervision -newlyqualified staffSkill mix- knowledge and support so that staff of all levels and experience are supported in their daily workContinuing education, continuing professional development

Training for new techniques, equipment and technology

ISO 9001:2000 revised -> ISO 9001:2008 focusses on human resources and requires that personnel be “competent” rather than “qualified”. ISO 9001:2008 states that competence shall be based on “appropriate education, training, skills and experience”. These changes are given in section 6.2.2 of ISO 9001:2008 entitled “Competence, training and awareness”. There are five requirements in the section:“a) determine the necessary competence for personnel performing work affecting conformity to product requirements,b) where applicable, provide training or take other actions to achieve the necessary competence,c) evaluate the effectiveness of the actions taken,d) ensure that its personnel are aware of the relevance and importance of their activities and how they contribute to the achievement of the quality objectives, ande) maintain appropriate records of education, training, skills and experience.”The two new requirements are c) and d).Reference: International Organization for Standardization, Quality management systems - Requirements, ISO 9001:2008, Geneva (2008).

CommunicationCommunication -between disciplines, co-workers, includes documentation - written information QMS is the communication method Recognition and Respect for person ‘doing theirjob'

Done through the Quality Management SystemIn a culture of recognition and respect for person doing ‘their' job

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Equipment selection ATP commissioning QA-QC

• General Terms of QC and QA in cancer management• Equipment selection• Procedures - Quality Control / Quality Assurance I

Acceptance Tests■ Calibration of Source■ Afterloading equipment and implants■ Applicators and appliances■ Organization and clinical cases

• Commissioning of the Treatment Planning System

•QA is necessary to ensure the patients treatment is delivered as prescribed, with minimal dose to healthy tissues and minimal radiation exposure to staff.•All those procedures that ensure consistency of the medical prescription and the safe fulfilment of that prescription as regards dose to the target volume, together with minimal dose to normal tissue, minimal exposure of personnel and adequate patient monitoring aimed at determining the end result of treatment.•QA is accomplished by defining and establishing the process and procedures that are followed.•Divided into 2 areas: Devices, treatment units, planning computers commissioning etc. Not covering in this talk.

and Procedures, implantation, imaging, dose calculations, treatment delivery.

Quality Control is the execution of the QA program and involves:Corrective Action -stepstaken to address deficits, issues or problems that are identified through the quality control process.

Clearly, there are marked differences between quality guarantee and quality control.• Assurance of quality is a set of preventive activities, which are focused on processes.• whereas quality control is a detection activity, which is focused on detecting the

steps in the process are completed and correct.• Assurance defines the standards to be followed in order to meet the prescription requirements.• whereas quality control ensures that these defined standards are followed atevery step.•This is done by assessments and checks that document the completion of stepsthroughout the planning and treatment process.The terms “quality assurance” and “quality control” are often used interchangeably torefer to ways of ensuring the quality of a service or product. The terms, however, havedifferent meanings.Assurance: The act of giving confidence, the state of being certain or the act of makingcertain.Quality assurance: The planned and systematic activities implemented in a qualitysystem so that quality requirements for a product or service will be fulfilled.Control: An evaluation to indicate needed corrective responses; the act of guiding aprocess in which variability is attributable to a constant system of chance causes.Quality control: The observation techniques and activities used to fulfil requirements for quality.

Errorsarise from cognitive problems understand in relation to the individual reduce by improving skill and/or information

Violationsarise from motivational problemsunderstand in social context and/or with reference to rules reduce by improving attitudes, morale, culture

•Factors built into Hardware and Technology that can contribute to a Quality Assurance program•Highly complicated differentiated system

•Factors built into Systems and RulesRequire compliance: used here in sense of cooperation1. the act of conforming, acquiescing, or yielding2. tendency to yield readily, esp. in a weak and subservient way3. conformity; accordance4. cooperation or obedience•and adherence might be a better descriptor, want staff to support systems and rules 1. the quality of adhering; steady devotion, support, allegiance, or attachment

Factors built into People and CultureNeeds to be awareness and willingness to change to ensure a QA program thrives

•Factors built into Hardware and Technology that can contribute to a Quality Assuranceprogram•Automation•Early warning systems in radiotherapy that means things like dose action points •TRAINING whenever equipment is replaced, software is upgraded

•Factors built into Systems and Rules•Compliance - be wary of this....define....don't just want forms/checklists completed forcompleteness sake, they have to be completed in the spirit of adherence this is a workplace culture that has to be nurtured and encouraged•Standardisation -rulesand practices have to be consistent standardisation is a useful tool to increase predictability•Checklists - Should not be taken for granted -theseare signed (be they electronic or paper based) people are responsible for their actions under this systemChecklists are not the starting point for improving equipment performance and reliability. They merely summarize the critical tasks or steps that are covered in detailed procedures and training. They serve as visual cues or reminders of important points learned in training sessions.

•Redundancy -throwingout the old get rid of ‘hangover' procedures that waste time and burden people for no real gain

•Guidelines procedures and protocols are multiply but there is evidence that compliance is patchy•TRAINING whenever new policies and procedures are introduced•Factors built into People and Culture•Need to overcome entrenched status hierarchies that often hinder accountability low status passes the buck high status blames those below•Make/encourage people to be responsible for their actions be accountable for theiractions•Ensure Staffing levels are appropriate to embrace QA principles these should not beburdensome if they are seen as extra work they will be avoided neglected refused•Have realistic Schedules•Have a continuing Education program•Open channels of Communication•Foster a culture of Team work•Safe ergonomic Work environment

•Need identified -toensure patient safety•There has to be an agreement by all involved in service delivery to use and adhere to the system in place•Quality Control is the execution of the QA program and involves:• Corrective Action -stepstaken to address deficits, issues or problems that are identified through the quality control process.•Won't spend anytime on this -thisis the reporting system Quality Control measures identify compliance with agreed standards practices•When standards, practices are not met and non-compliance or error is detected, these are reported back to Quality Manager via electronic system called Riskman •Non-compliance and errors are investigated according to the severity•Measures (further or adjusted quality control measures) are put in place to prevent or avoid non-compliance and errors

•The quality control measures act as checks or brakes -ifsome are not done -other processes cannot proceed•So corrective measure may be to stop a process or procedure because preceding work has not be QA'd

Clearly, there are marked differences between quality guarantee and quality control.• Assurance of quality is a set of preventive activities, which are focused on processes

• whereas quality control is a detection activity, which is focused on detecting the steps in the process are completed and correct• Assurance defines the standards to be followed in order to meet the prescriptionrequirements• whereas quality control ensures that these defined standards are followed at everystep.•This is done by assessments and checks that document the completion of stepsthroughout the planning and treatment process

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Overview of Quality Management System (QMS) in Radiotherapy

Ensure all staff are familiarwith and use the same

Purpose policies, proceduresmethods, work instructionsforms and records

Applies to all quality systemdocumentation used withinScope the division of radiationoncology

Radiation Therapy ServicesQuality Manager to oversee

Responsibility the implementation of andconformity with thisprocedure.

•The quality management system at Peter Mac is a documentation system in electronic format managed by a dedicated Quality Manager•The Radiation Therapy Services Manager is a Senior RT who oversee theimplementation of and conformity of the quality system documentation•Documents are prepared by relevant staff and the person in charge of the area•Documents are reviewed by other staff working in the area and the section/unit head•The person approving the document has the responsibility to ensure that the content is correct

•Authorisation of the document is the responsibility of an Authorizing officer of the relevant area

Scope: the area covered by an activity, topic, etc; range:

•The Quality Management System contains policies, procedures, work instructions and forms and records.

•In some instances work instructions may be represented by a flow chart or series of images.

•Content and format are standardised•This ensures consistent use of layout and terminology

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DRO QMS -Procedure Issue Date: 16/07/10 ./“iif

Title: Brachytherapy Process Doc. No: 12.1

1 PurposeTo describe the general Brachytherapy process and the responsibilities of the various disciplines involved in the delivery of Brachytherapy.

2 ScopeDivision of Radiation Oncology - Brachytherapy

•Procedure: Steps should be clear and concise with diagrams and flow charts when applicableA clear numbering system should reflect the system used within this procedure

IAEA 3 ResponsibilityRadiation Oncologist (RO) Radiation Therapist (RT) Medical Physicist Radiation Safety Officer Theatre staff

4 Definitions4.1Brachytherapy: a method of radiation therapy in which sources are used to deliver a radiation dose at a distance of up to a few centimetres by surface, intracavitary, intraluminal, or interstitial application.

5 Procedure

5.1 Equipment ListHigh Dose Rate Brachytherapy Unit (HDR)Plato Planning computer. Oncentra Planning Computer Variseed Planning computerBrachytherapy applicatorsUltrasound unit (Flex focus) & Transducers

5.2 Quality AssuranceQuality assurance of the HDR unit is the responsibility of Medical Physics.Quality assurance of treatment planning and delivery is the responsibility of all brachytherapy personnel.

5.3 SterilisationAll equipment used in theatre must be sterilised. This is the responsibility of Central Sterile Supply Department (CSSD) staff. Ensuring that equipment is sent to CSSD in time for scheduled treatments: storage of sterilised Brachytherapy equipment and ordering of equipment is the responsibility of Brachytherapy staff.

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Document content and format

AssociatedDocuments

• Work instructions and records that may be used when performing the procedures

References• List the publications and

any other information sourced in the preparation of the procedure.

Document header &

footer

• Header contains document type, issue date, document control number and title

• Footer contains information relating to author, Version number, page number, revision information and date

Note Revision is built into the systemRelevant staff are notified when documents need to be revised

Documents can be removed at any time if there are changes to policies or procedures

Using the QMS in Radiotherapy•Procedures- outlining methodology and tasks•Work instructions- how to perform tasks•Assessments- detailed checklists covering all aspects of planning and treatment ensuring all components of procedures have been completed •Assessments and checklists have explanatory notes•Record of completion and Approval before next phase can commence (Records serve as measure and review of performance)•Becomes a part of checks and balances

examples of some QC measures•examples of procedures i.e. Simulating a patient for whole pelvis EBRT•examples of tasks involved i.e. Check prescription•Identify patient•Explain procedure to patient•Ensure consent obtained•Correct treatment and positioning aids•Position patient•Area to be imaged

•Two people working together•Photo documentation of reference marks and tattoos•Assessments - indicate with electronic signature when task completed

•Safety notes must be read and signed each time an RT is rostered to a new area even if they are familiar with the area

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Acceptance

• After installation of the equipment, the acceptance tests (AT) must then be performed to demonstrate that the equipment meets or exceeds the tender specifications. Frequently, acceptance tests follow a protocol supplied by the manufacturer, but the purchaser may develop their own protocol. In either case, the acceptance test protocol must be part of the purchase order for the equipment, so that both sides agree to what constitutes acceptance of the equipment and both sides are aware of the expectations of the other party.

• Acceptance test protocols specify which tests will be performed, which equipment is used to perform these tests and what the results of these tests should be. They constitute a legal document in which the medical physicist confirms that the equipment meets the specifications of the bid.

• The medical physicist is responsible for carrying out the acceptance tests with the manufacturer representative.

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Commissioning

• Commissioning follows completion of acceptance, and involves all those tasks necessary to have the brachytherapy equipment ready for patient use. An import part of commissioning is establishing baselines for ongoing quality control testing.

• A number of areas need to be considered:■ Source calibration■ Checks of the afterloader and implants■ Checks of the applicators and appliances■ Checks of the TPS■ Clinical service organisation (staff training, documentation of

clinical procedures, establishing emergency procedures etc.)

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Quality Control (QC)

• Quality control refers to all those regular tests performed to ensure high quality patient treatment.

• Performing quality control testing and acting on any results ensures that the quality of the service provided by the equipment is maintained throughout its 10 to 15 year life cycle.

• Quality control tests can separated into those test which are equipment-specific and those which are patient-specific.

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Quality Control

Many international recommendations exist for the quality control of brachytherapy equipment:• ESTRO Booklet No. 8• IAEA PUB 1296• IAEA TRS 430• CAPCA, Brachytherapy Remote Afterloaders, 2006

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• General Terms of QC and QA in cancer management

• Equipment selection• Procedures - Quality Control / Quality Assurance /



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Brachytherapy equipment

• HDR afterloader• Applicators, catheters etc.• Treatment planning system• Patient imaging systems• Networking, communication standards• Dosimetry equipment• Radiation safety equipment• T reatment couch

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Radiation safety equipment

• An area radiation monitor in the treatment room, connected to the door interlock with an audio signal safe against power failure and independent of treatment equipment

• A portable radiation monitor instrument at the entrance of the treatment room

• Highly recommended: an area radiation monitor with an audio signal at the entrance to the treatment room

• Emergency container and emergency source handling devices at the entrance of the treatment room door

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Equipment management

SPECIFICATION AND PROCUREMENTSelection process based

on needs and performance standards

Checks system conforms with specifications

Getting the system ready for clinical use

Process to ensure proper operation is maintained

Engineering process to ensure reliable service

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Specification

• Brachytherapy equipment will need to be specified and arrangements made for their purchase in a cost effective manner. These arrangements are often made through a tender process or through negotiations with suitable vendors.

• As well as technical specification of the equipment the following also need to be considered:

■ Compliance of equipment with quality and safety standards;■ Acceptance tests and conditions to correct deficiencies revealed during

acceptance;■ Warranty conditions;■ Enforceable assurances on availability of maintenance support, manufacturer

support, manuals and spare parts;■ Possible training of local engineers.

Please refer to IAEA PUB 1296 for the complete specification

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We mainly focus on HDR

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Specification Of Source Intensity

All international recommendations indicate the convenience of specifying the sources exclusively in units of Reference Air Kerma Rate (RAKR) on Accredited Calibration Laboratory documentation (standard sources and calibration factors of measuring systems), manufacturer certificates, TPS,

prescription and reporting (CFMR11983, BCRUM 1984, ICRU 1985, AAPM 1987, NCRD 1991, BIR 1993, NCRD 1994, ICRU 1997). This quantity is

obtained at 1 meter and the units are juGylr1.

However in practice, the classical specifications are often maintained. This approach can lead to a high probability of errors in clinical dosimetry,

where conversion factors from RAKR to "activities" are used for different isotopes. (Jayaraman etal. Med. Phys. 1983)

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In the past, the strength of a brachytherapy source was specified in terms of Activity, i.e., the number of disintegrations per unit time, or, for carrier- free sources such as radium-226, even simply as mass of a nuclide. The original definition of the curie (Ci) as the unit of activity was that

1 Ci equals to activity produced by 1 g of radium-226 (3.7 x1010 s-1).

The measurement of source activity presented problems, in particular for sources with filtration material surrounding the source, due to attenuation and scattering effects. Other alternate quantities that were introduced for specifying source strengths, but are no longer recommended for use, are the apparent activity and the milligram-radium-equivalence.

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AAPM (AAPM 1987) recommends that sources are specified in terms of Air Kerma Strength, defined as the product of the air kerma rate and the

square of the calibration distance

Sk(pGyh'im2) = K(pGyh'[) /2(m)

It is numerically equal to RAKR at 1 m with the same units. A unit for simplification of the equation defined as

lU = ipGyh'm2

has been proposed by Williamson (1991).

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Calibration of brachytherapy sources• In-air measurement technique

use up-to-date correction factors and carefully perform in-air measurementsFour effects (uncertainties) expressed as a function of distance between the source and the chamber(SCD- source chamber distance):

- chamber size (non-uniformity correction factor decreases with increasing SCD- scatter, which as a percentage of the total signal increases with increasing SCD- positional uncertainty (follows inverse square law and decreases with increasing SCD)- leakage current relative to the ionisation reading (increases with increasing SCD)

“ A practical criterion is that the distance between the chamber centre and the centre of the source must be at least 10 times the length of the source (HDR: 10-40cm) in order to ensure that the error introduced due to the point source approximation is less than 0.1 %” - make multiple distance measurements

• Calibration using well type chambersEasy and simple method: Only correction for source decay and temperature and air pressure is needed to obtain confidence in the stability of the instrument’s reading. Any sudden deviation of more than 0.5% in the check reading might indicate a problem

“minimum scatter condition” (1 m from any wall or floor)

• Calibration using solid phantoms (not for low energy sources) “only as a Quality Control tool if it has been checked by one of the other methods”In this check the ratio, q = MCI MP, of the measured charge in a phantom, MP, to the charged measured during the calibration, MC, should be constant from one source to another.

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Well Type ChamberWell type chambers provide an easy and reliable method for calibrating brachytherapy sources. The calibration point of a well type chamber is defined as the point at which the centre of the source is positioned during the calibration procedure; this point may differ from one source to another depending on the source length.

Picture taken at the General Hospital of Vienna

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Measurement of the source strength

In-PMMA measurement In-air measurement

Krieger phantom (DGMP 1999) conected to a Varian afterloader unit.

Picture taken at the General Hospital of Vi

Krieger phantom (DGMP 1999) connected to a Varian afterloader unit. For each phantom design (distance between sources and ion chamber, size and material of the phantom) and source type, the correction factor for lack of full scatter needs to be determined separately.

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The reference air kerma rate is a quantity specified at the distance of 1 m. The direct measurement at 1 m, however, is not always practical due to low signals and the possible high leakage currents of the ionization chambers

used. The reference air kerma rate, KR, may be determined from measurements made free in-air using the equation:

KR=NK-(Myt) -kair-k^-kn (d/drefy

where

•Nk is the air kerma calibration factor of the ionization chamber at the actual photon energy;

•Mu is the measured charge collected during the time t and corrected for ambient temperature and pressure, recombination losses and transit effects during source transfer in the case of

•afterloading systems;

•kair is the correction for attenuation of the primary photons by the air between the source and the chamber;

•kscatt is the correction for scattered radiation from the walls, floor, measurement set-up, air, etc.;

•kn is the non-uniformity correction factor, accounting for the non-uniform electron fluence within the air cavity;

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Well Type Chamber -

Air pressure p [hPa] : ____ 1005__ Temperature t [°C]: ___24___Ktp (ktp= (1012/p)*(273+(t/293)):___1.02172_

Air KERMA calibration factor (chamber: _Unidos1_ ) Nk: _0.0936__

SOURCE SPECIFICATIONS^__________________Reference Air Kef ma Rate!^468 mGy h '1 +/- 5% at 1 m

Measured X2012-05-01 19:55 CET<1’^ZApparent Activity: PBi| ( in 17 Pi) nl ili'inrrTmeasurement (3,4)

Source Type: MICROSELECTRON V2Capsule dimensions: 0.90 mm diameter, 4.50 mm length

Source pellet dimensions: 0.65 mm diameter, 3.60 mm length Source pellet form: solid Iridium

Radionuclide: Ir192 Encapsulation: single

Capsule material: stainless steel, AISI 316L ISO Classification: ISO/80/C63211

dal form certificate number: D/0070/S-96(REV.3)

Read out 1: _34.6_

Read out 2: _34.8_Read out mean: _34.7_

Source Strenght Sk: _3.3185_cGym2/h (Sk = readout mean * ktp * Nk)

difference: 0.3 %Sk= SkO EXP-(ln2*t/73.83)

t = 32dSk = 3.3086 cGym2/h

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Quality Control procedures of afterloading equipment and implants

• Safety systems

• Physical parameters

• Frequencies and tolerances

• Safety and radiation protection

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•Communication equipment. Observe that the television and intercom systems are working.

• Applicator attachment. Program the unit to send the source into each of the channels without attaching catheters or transfer tubes to the unit. Try to initiate a source run.

• Catheter attachment lock. Attach catheters to each of the channels but do not lock them in place, and try to initiate a source movement.

•Door interlock. Attach and lock a catheter to each channel. Program the source to dwell at the tip of the catheter. Leave the door open and try to initiate the source run. Close the door. Initiate the source run. Open the door while the source is out. Check to see that the run is aborted. Inspect the fault indication on the console and the printout from the unit to ensure that a correct record of the fault has been made.

• Warning lights. Observe warning lights during a source run.

• Room monitor. Listen through the intercom for an audio signal during a source run. Use the room cameras as visual monitors.

• Hand held monitor. Immediately on opening the door during a source run, hold the handheld monitor in the doorway and see whether it indicates the presence of radiation. The reading of the monitor itself should be checked regularly against a known source (level) of radiation.

• Treatment interrupt. During a source exposure, press the interrupt button to abort the run and ensure that the source is retracted. Inspect the fault indication on the console and the printout from the unit to ensure that a correct record of the fault has been made.

• Emergency stop. During a source exposure, press the emergency stop button to abort the run and check that the source is retracted. Inspect the fault indication on the console and the printout from the unit to ensure that a correct record of the fault has been made.

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• Timer termination. Test that a source exposure continues until the time elapsed equals the time set on the timer.

• Obstructed catheter. Attach and lock an obstructed catheter or a catheter that has been curled into a loop with a radius of curvature too small for the source to negotiate near the end. Check that the obstruction or the restriction due to curvature being too tight is detected. Note: before starting the procedure, verify with the manufacturer to avoid possible damage to the system.

• Power JOSS. Check that an interrupt of the AC power during treatment (open the circuit or unplug the unit, see manufacturer’s instruction manual) results in immediate source retraction. Check, that upon restoring the power, the treatment parameters and the remaining dwell time are correctly recalled. Some machines have a back-up power supply, so that the treatment continues normally despite an ac power loss. For such equipment the check that should be performed would be to ensure that the treatment is not interrupted by the power failure. Inspect the indication on the console and the printout from the unit to ensure that a correct record of the fault has been made. Integrity of transfer tubes and applicator. Perform a visual inspection of the transfer tubes and applicators.

• Leaking radiation. Check that the radiation level at 10 cm and 1 m from the afterloader safe with the source retracted is lower than the level specified in the legal requirements.

• Contamination test, check cable. Attach an applicator, position the check cable in the applicator (with the manual controller) and disconnect the applicator. Perform a wipe test (see section 4.4) of the check cable. If this procedure is not possible, see the manufacturer’s instruction manual for methods to perform a similar test.

• Contamination test, applicators. Attach a single use plastic applicator to the unit. Perform a source run. Disconnect the applicator and perform a wipe test (see section 4.4) of the inner applicator wall after cutting it. Alternatively place the entire applicator in a well-type crystal counter in order to detect any gamma emitting contamination.

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Quality Control procedures of afterloading equipment and implants

*-<X • Safety systems




Qy IAEA Physical parameters•Source positioning accuracy

•Length of treatment tubes

•Transit time effect

Mt0fu(t)=l----------

M, (t)

•Timer consistency

t.. is dwell timeMt0 is the electrometer reading at time 0

(zero dwell time, only dose contribution during Source transport) and

M, is the electrometer reading for dwell time t.The value for t= 0, M(0 is determined for the specific geometry

By programming dwell times in the range of 2 to 120 seconds and then extrapolating to t= 0

m•Timer linearity

•Source positioning accuracy

User Manual 0 Nucletron

20. Flexitron; Distance to Most Distal Dwell Position

(3)

(1) Channel selector (3)(4)

. (5)

i-n (4)

Lm = L,+L„ - (Lp+Ls+Lc)Lm: Maximum source distance (mm)

Transfer tube reference length Needle length of the needle to be used Needle tip length (varies dependent on needle type)Safety clearance between the source tip and inner end of the needle Center of source length

Centre of source

Most Distal Dwell Position(5)(6)

L

See Detail A

Detail A

Size and positioning reproducibility of an 192lr brachytherapy stepping source

A. Berndt, D. W. Rickey, S. Rathee, and J. BewsCancercare Manitoba, 100 Olivia Street, Winnipeg, Manitoba, R3E 0V9, Canada and Department of Physics, University of Manitoba

(Received 7 May 1999; accepted for publication 12 October 1999)Detector

72t

Catheter

Source Translation

SourceX

3

Table II. Source position reproducibility measurements.

Measurementseries

No. of trials

Standard deviation in source position (mm)

Source retraction method

1 6 0.12 interrupt and resume2 7 0.030 interrupt and resume3 15 0.097 new treatment

<------- 152 mm--------- ►

Fig. 1. Schematic showing the detector, the source, and the lead blocks used to collimate the source. The dimensions of the slit are 025X10X152 mm3. The detector and the collimator are held stationary, while the source is trandated naet ih** dit

-<>.-> -0-2____ 0.0 0.2____Translation Stage Position (mm)

iUi

The imprecision in the source position was found to be less than 0.12 mm. The source length and width were found to be 2% and 15% larger than

those specified by the manufacturer.

Reprinted with Permission American Association of Physicists in Medicine :BERNDT, A., RICKEY, D. W., RATHEE, $., BEWS, J., Size and positioning reproducibility of an 192 Ir brachytherapy stepping source, Med. Phys. 27 (2000) 129-131.

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Quality Control procedures of afterloading equipment and

implants

Safety systems

Physical parameters



Q9IAEA 1 Frequencies and tolerancei of quality control testsfor HDR/PDR afterloading equipment

Description Minimum requirementsTest frequency Action level

Safety systems

Warning lights daily/3M"

Room monitor daily/3M‘

Communication equipment daily/3M’

Emergency stop 3M

Treatment interrupt 3M

Door interlock 3M

Power loss 3M

Applicator and catheter attachment 6M

Obstructed catheter 3M

Integrity of transfer tubes and applicators 3M

Timer termination daily

Contamination test A

Leakage radiation A

Emergency equipment (forceps, emergency safe,

survey meter)

daily/3M’

Practising emergency procedures

Hand crank functioning

Hand held monitor

A

A

3M/A”

Table reproduced from ESTRO Booklet No. 8, 2004 with permission courtesy ofESTRO

Physical parameters

Source calibration SE >5%

Source position daily/3M* >2 mm

Length of treatment tubes A >1 nun

Irradiation timer A >1%

Date, time and source strength in treatment unit daily •

Transit time effect A

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Daily checksMon Tue Wed Thu Fri

Safety systems 09.07.12 10.07.12 11.07.12 12.07.12 13.07.12

Visual inspection z z z zRoom monitor z z z z z

Communication equipment z z z zWarning lights z z z z z

Test run z zSource strength [cGym2/h] 2.3494U 2.3275U 2.3058U 2.2868U 2.2628U

No irradiation with open door possible z z z z z

Remarks

Signature KK EA AR NW KK

1% source decay per day

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Weekly checksSystems

Irradiation timer termination after 30s (20s) 30.1s

transfer time 10.4sSource strength [cG m2/h] (printout) 2.2775 U

Source strength [cG m2/hl (calculated) At= 72 days 2.2771 UEmergency equipment (forceps, container, survey meter)

Manuals, Afterloader log-book, emergency info

Dose monitors, dedectors

Remarks

Date/signature 12.7.2012 /GW

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Monthly checksSystems

Source positioning

INVIVO-probe calibration

Date/sig nature 29.7.2012/GW

3 Monthly checks

Door interlook 1/Treatment interrupt / Emergency stop

Applicator and catheter attachment

Date/signature 29.7.2012/GW

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Quality Control procedures of afterloading equipment and

implants

• Safety systems




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Emergency stop motor

Wire-inswitch

Check cable drum (groved)

Belt

Check cable stepper motor

Modem AfterloaderCable guide tubes

Source cable drum (groved)

Source stepper motor

Shaft encoder (optical)

Safe

Referenceoptopair

Shaft encoder (optical)

Channel selection tube

(stainless steel)

Encoder(optical)

Indexer stepper motor

Channelselectoroptopair

Indexer

Optical switch locking ring

microSelectron-HDR

Figure reproduced from ESTRO Booklet No. 8, 2004 with permission courtesy of ESTRO

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• Emergency equipment (forceps, emergency safe, survey meter). The presence of this emergency equipment close to the afterloading unit should be checked. Surgical supplies, emergency instructions and the operator’s instructions must be available. If applicable, a list of error codes and their meaning must be available near the equipment.

• Practising emergency situations. Emergency procedures must be practised by all personnel involved in brachytherapy treatments. The goal of such procedures should be to keep the dose to the patient and to the personnel as low as possible.

• Hand crank functioning. The function of the manual source retraction crank must be checked. Detailed instructions are provided by the manufacturer of the system.

Policy

• comes under hospital safety manual procedure practice equipment • Overseen by radiation safety officer

Procedure• Outlines actions and responsibilities• Details equipment available and how to use

Practice• Should be routinely scheduled• To keep staff ‘fresh'• To ensure newly rostered staff are trained

Participation• Include all personnel who have a stake in brachytherapy• This includes personnel in adjoining areas who may get distressed if they hear an emergency

code• Don't forget nurses, anaesthetists, theatre technicians• Core group of medical physicists and radiation therapists

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Room Design Designation of areas

• Areas accessible to general public• Supervised area

■ control console area• Controlled area

■ treatment rooms■ source storage & preparation room (manual

LDR)

11

Nature D <■

1 mSv/yr

1

11

Monitored (supervised) area D > 1 mSv/yr|1

1controlled area D > 6mSv/yr .

11

1Off-limits area 1

111111

D > 3 mSv/h |

1111

1I

11

IAEA

Radiation SafetySource strength

Afterloading operating time (e.g. HDR 12h PDR 32h per week)O Operating personal / staff (20pSv per week -> 1 mSv per year) Q

L

HDR afterloadingO <-«

HDR afterloading-^fc--

IAEA

Radiation SafetySource strength

Afterloading operating time (e.g. HDR 12h PDR 32h per week)O Operating personal / staff (20pSv per week -> 1mSv per year)

L2.

Tablereproduced from ESTR0 Booklet No. 8, 2004 with permission courtesy of ESTRO

HHDR afterloading

O <-

HDR2

HDR3

HDR' afterloading

ft I s ' "O mdr\ \

S \ X

Table 4.2 Radiation protection data for a number of radionuclides (most data taken from Dutreix et al 1982; see also ICRU 58, 1997).

Nuclide Average energy (in MeV)

of the emitted photons

Half life First HVL in lead

(in mm)

TVL in lead

(in mm)

TVLin concrete*

(in cm)

“Au 0.42 2.7 d 3 11“Co 1.25 5.3 y 12 42 22,37Cs 0.66 30.2 y 6.5 22 17.5“I 0.028 59.4 d 0.025 -

,<0Pd 0.021 17 d 0.02 -■«lr 0.38 74.0 d 6 16 14.7

“Ra** 0.83 1600 y 16 45 23.4

K....* o

eatmentsparation

1-0

o

’Density of concrete, p = 2.35 IO5 kg-mJ.** Note that numeric values may differ depending on the type of filtering used. HDR bunker at the MUV

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Exposure of Individuals -TRAK

The dose to the individual due to the exposure to a gamma source or to a set of sources is determined by the strength of the source(s), the time of irradiation and the distance from the sources.

The quantity to indicate the strength of a source is the reference air kerma rate, kr expressed in the units pGyh-1 at 1 m. The product of the reference air kerma rate of a source used in a treatment (or during an exposure) for a given duration tj? summated over all sources, is called the total reference air kerma,

TRAK = Ym-Q

This product thus gives us a quantity that can easily be used in radiation protection calculations at any distance, simply by using the inverse square law relative to the distance of 1 m: Kair = TRAK I r2, for the air kerma Kair at a point at distance r.

KR

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Commissioning of Applicators„The process in which the (clinically relevant) location of the dwell positions in

relation to each other or in relation to reference points in the applicator are determined/verified and the transfer into the treatment planning system is checked”

[» Characteristics of applicators |- Material (dosimetric influence, sterilisation)- Dimensions- Connectivity to afterloader (transfer tubes)- Indexer length and off-set (distance of 1st or most distal dwell position to tip-end)

|« Visibility of applicator in sectional imaging |- Distortion of dimensions- Artefacts (appearance of applicator tip-end: E g. needle tip-end)

[• Verify source-path |- Predefined (from vendor provided) source-path stored in Applicator library- Direct reconstructed by the user following direct or in-direct reconstruction methods

More details are in the lecture on treatment planning

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Integrity of applicator materials Visual inspection, depending on their use: before or after each treatment

Fixation mechanisms Check each fixation screw and mechanism for proper functioning before and after treatment

Shielding in the applicators Check for presence and position of shields included in the applicator at acceptance (radiography)

Source positioning Autoradiography whenever applicable for verification of source pos. at acceptance or when

there is suspicion of (length) changes

Identification of connecting mechanism

Check the identity of the applicator in relation to its connection to the afterloader at acceptance

Sterilisation procedures Check for instructions and follow these meticulously to avoid unintended damaging

Validity of dose distribution in relation to specific applicators

Carefully check the applicability of any dosimetrical “atlas” for precalculated and tabulated treatment

times, at acceptance

Radioactive contamination Careful handling with, e.g., Sr-90 applicators to avoid radioactive contamination and checking of

tubes in Nal crystal to detect leakage or contamin.

Q*)iaea Titanium alloys used for manufacture of titanium needles (VT-6, RK-20, VT1-0)

Chemical composition, (%)

Quality Check for Titanium needles “indexer length and off-set”

\Allow

Element's

VT1-0(GOST19807-91)

For comparing (ASTM

Designation: F67-83) Grade 11

VT-61 RK-203Perspec

tive alloy

PT-7M

H 0,010 0,015 0,015 0,005 0,003C 0,07 0,10 0,10 0.02 0,03N 0,04 0,03 0,05 0,02 0,01O 0,2 0,18 0,20 , 0,07 0,09A1 0,03 6,10 - 2,10Fe 0,25 0,20 0,60 - 0,06Si 0,0! - 0,10 - 0,01Cr - - -Mn -Zr 0,30 20,0 2,70V 4,30 -

The sum remaining imourities

0,1 - 0,3 0,1 03

IAEA

Acceptance Test for Applicators on Flexitron Afterloader Isodose Control Heyman Applicators

Length 300 -> Offset = 4mm Capsule size

Tip end 1st dwell pos.-------------* ■

av markerX-ray marker

A-APictures courtesy of Daniel Berger, Medical University of Vienna

Geometry

Documentation

• Indexer lengths > QMS doc

BRACHYTHERAPY INDEXER LENGTHS AND EQUIPMENT GUIDECatheter description Transfer cable

usedIndexerlength

First dwell position

Gynaecology Rotterdam Stainless Steel applicators (Tandem and Ovoids)

Individually numbered 12 3

transfer cables1254 mm long

1500 mm 7 mm trom external tip ot applicator

'XMRI compatible applicators (Tandem and Ovoids)

Individually numbered 12 3

transfer cables 1260 mm long

1500 mm 7 mm from external tip of applicator

« Plastic curvedtandemMRI compatible

Individuallynumbered#3 transfer cable 1260 mm long

1500 mm 7 mm from external tip of applicator

•Equipment / applicators are the responsibility of the radiation therapist and medicalphysicist•Need to ensure all personnel using equipment are familiar with geometry, dimensions, composition•Important to have this information accessible at time of planning and treatment

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Documentation

Composition • Sterilisation method• Strength, handling

Equipment Currentsterilisationmethod

Future sterilisation method

Standard CT/MR applicator set

ETO Any new equipment purchased can be autoclaved at 134°C

hr, MaendAxocbe cT^lereOioe

Ht/lWFI3IKQBTF ..✓ ✓

rtuSeTC r.te ✓ ✓Fbcrj M-ctarerr PPSU ✓ ✓

/ ✓Redd tenctop. PP5U 7 ✓twho SuraesSsd 7 7

Vaginal CT/MR applicatorset

\OETORevision ,03121°Cautoclave

ten MartAtnoriae Eff^ewOwie

HX/I3TEIJI’OBCf I34XJ273";

Rnccr 03 xipx ✓

HTiierreT-tej/Epotytoyw^tew

QjafberRewcriOtcrtigW R£rox06xipx /

Kilter Olxipif 7

CjWsr Faxon RntcrDixIps- rcrax 03 x bper /•tmsal 3x PPSJ F-eitcr Warber Reraor 03 ar bjfer ✓

Composition•Sterilisation method, need to know to ensure fidelity of equipment•Need to train brachytherapy and CSD staff to look for cracks wear and tear•All equipment must be examined by the radiation therapist prior to procedure

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Ouantitv ’Secure storage uuanmy . Regu|araudjt

Documentation

Pictures courtesy of Jamema Swamidas

CO Lt*—^25

• All applicators individually wrapped• All applicators labelled and checked by two radiation therapists• Locked storage cupboard• Labelled shelves

• Equipment/applicator log & management system

• Needed to manage lists to ensure sufficient equipment available (if equipment not available clinical risk ensues)

• Supply has to exceed demand

Equipment comes with expected life span - need replacement policies

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Acceptance Tests■ Calibration of Source■ Afterloading equipment and implants

IAEA

Check your ability to localize a point!

Roue A et al, The ESTRO-EQUAL audit on geometric reconstruction techniques in brachytherapy, Radiother Oncol, 78 (2006) 78-83 copyright Elsevier, reproduced with permission

£ 3.0

<5> 2,0

x§ 1.0

0.0

Good

Mill I .U-

md = 0,02 mmA =0,30 mm

Courtesy of Dimos Baltas

IAEA

Check your ability to localize a point!


EE

5.0

4.0

3.0

1.0

Good

Hill i -.M-

md = 0,02 mm A =0.30 mm

20 40 60 80 100 120 140Distance in mm

Courtesy of Dimos Baltas

To emphasize the importance of applicator reconstruction demonstrated in this paper by Tanderup et al. 2008

This report arrives at a number of conclusions. In ring applicators, the HDR 192Ir source path is dependent on the geometry of the ring. The geometry of the ring causes the afterloader source cable to travel along a characteristic path that is different comparedto the path travelled by the source. This has the effect of introducing significant offsetsin the expected position of the source—up to 6.1 mm for 026, 030 and 034 mm Nucletron interstitial ring applicators.The commercially available source path models provided by Nucletron were found to be significantly different compared to measured data. In addition, significant differences in source position were observed between sets of the 026 mm ring applicator leading to the conclusion that, in some cases, it may not be possible to characterize all ring applicator sets of the same size with a single source path. Consequently, this report suggests that multiple ring sets of the same size be independently commissioned before the attempt is made to characterize them with a single source path for clinical use. The use of multiple sources was observed to have negligible impact on variation in source position. The total expanded measurement uncertainty (k = 2) averaged over all dwell positions was observed to be 1.1 ± 0.1 mm (026 and 030 mm) and 1.0 ± 0.3 mm (034 mm).

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Quality Control - Reconstruction

QC - reconstruction standardloadingpattern

o 4

*■» *

• IS]• l|22]

3

$ 8 L

9 S

3

3Seo]A 1 ft 1

1

wrong source path reconstruction

correct source path reconstruction

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Organisation

Definition of the treatment teamSpecification of the tasks of the individual team membersDesign of the information flow, the use of formsScheduling of the patient treatment:

• Information to patient and team members• Reservation of rooms (treatment room, OR, CT, simulator, X-ray)

Radiation protection:• List of team members involved in the treatment• Making radiation protection equipment available for treatment room

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Training

Identification of team membersTasks of the individual team membersTeaching of general proceduresTeaching of specific tasksTeaching and practising of emergency procedures (initially and repeatedly)

IAEA

Emergencies

Description of emergency planAvailability of safety equipment:

• Storage and transport container• Tools, cable cutter, long forceps• Radiation monitor

List of error codes available at the treatment unitList of telephone numbers of responsible and expert persons

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Tumour specific protocols

Target volume descriptionPrescription data:

• Dose prescription• Prescription point or surface• Critical organs

Treatment technique, treatment unit, applicatorsTechnique for localisationTechnique for optimisation in treatment planningTreatment team definition: during insertions, during planning and treatment

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Localisation protocols

Description of localisation techniquesDescription of X-ray catheters or dummy markers Description of contrast media to be used Avoidance of distortions in CT or MR imaging Phantom testing of geometrical reconstruction techniques Double check of outcome of reconstruction

Review of plan and treatment documents

Check of completeness of printed informationCheck of consistency of plan with treatment prescriptionDouble check of data by independent second personIf possible perform (simple) manual calculation of treatment timeSigning of documents before treatment starts by physician and physicistCheck if emergency procedures are fulfilled (table 7.3)Check prints of treatment report after completing treatment: sign documents Store the keys of the treatment unit at safe place

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QA and QC in brachytherapy

• Uses fewer fractions• Larger dose per fraction• Greater biological effect and impact

BUT• Brachytherapy planning computer and

treatment console not linked to Record and Verify System by now

• Rely on manual checks

• Lots of information to be gathered considered analysed and checked in short space of time

• Far fewer fractions, larger dose per fraction, greater biological effect and impact NEED to get it RIGHT• Quality Control measures exist• Assessments and checklists are paper based• Record of completion is paper based

Picture courtesy of Sylvia Van Dyk

IAEA

Weekly chart round Review prescriptions Review EBRT plans Review pre-tx MRI

Review plans Approve plans Answer queries

Quality control measures inbrachytherapy

Chart round picture with brachytherapy personnel, TPS computer, PACS, Verdi (electronic history)• Use Record and Verify System for appointments• Can check EBRT part of treatment• BT treatment scheduling managed within brachy unit (total time for tx Cx < 8 weeks)

•Checklists used to show completion of tasksIn theatre first day EUA check responseUltrasound Under Anaesthetic (with TV US) image based check on response to EBRT Compare to pretx imaging on PC in theatreUse image guided applicator insertion, applicator position optimisationImage based volumeTreatment planPrescription Dose check (correct for EBRT protocol used)Treatment plan performed by one RT independently checked by separate RT Cardinal dose points checked -ICRU38 bladder, rectum, vaginal mucosa Onscreen check of all treatment parameters -two person treatment check Physics /RT

Radiation safety checks - independent radiation monitorsMRI patient travels with RT and nurseMRI reconstruction - independently done and checkedDoses to target checked, to OAR extrapolated for four fractions Reported at next chart round, coverage checked with Radiation Oncologist

As brachytherapy treatment unit is in an operating theatre, we follow WHO guidelines for checking the patient into theatre.

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Quality control measures in brachytherapy

Intraprocedural ultrasound used to

•Identify position of uterus •Determine tumour response

•Identify uterine canal •Guide ‘sound’•Guide dilator

•Guide applicator placement •Optimise applicator position •Measure treatment volume •Calculate conformal plan

•Check iso-coverage at each insertion

Pictures courtesy of Sylvia Van Dyk Pictures courtesy of Sylvia Van Dyk



• Use ultrasound to identify uterine canal• Insert dilator under ultrasound guidance • Insert tandem under ultrasound guidance • Measure and verify treatment volume• Create treatment plan• Check iso-coverage for each insertion

Tandem length Cylinder Width Ovoid Size Ovoid Type Ovoids Loaded

Angle of Bladder Balloon to Flange



IAEA

Volume verification with US at PeterMac


Brachytherapy • Gynaecology Planning using Ultrasound

These are processes or procedures that are described in QMS document Quality control measures are the recording of them.

Volume verification•Applicator type recorded on QMS form•Volume measurements recorded each insertion•MRI measurements also added to this form

• Planning at TPS• One medical physicist or dosimetrist plans• Cross checks Record and Verify System for EBRT dose• Protocol for BT dose based on fractionation schedule• Plans treatment• Monitors OAR doses ICRU38: Rectum, bladder, vaginal mucosa• Checks coverage with RO• If OK• Independent medical physicist or dosimetrist checks plan on-screen using QMS

document - On Screen Checklist• Weakness in paper is that processes can progress without all elements being signed

off• (in electronic systems it is possible to add dose alerts that do not allow progress until

all elements are finished)• As staff member completes task they sign off• Separate staff does independent check later• Again, review plan and coverage at chart round with RO

IAEA


Treatment plan is considered primary source

Once checked and approved plan is printed

• Plan is sent to Treatment Control System

• Pre-treatment report is printed and cross-checked by radiation therapist and

medical physicist All checks and check cable

run performed before treatment commences Radiation therapist/medical

physicist cross checking plan and TCS printout

•Checklists act as record of completion they are signed so people take responsibility and are accountable

Treatment checklist highlights the quality control measures that need to be checked each treatmentPlan - patient identification, plan name, prescription, dose, customisation file, Air Kerma, applicator, indexer length, source positions and times Treatment -manyphysical factors that relate to our unique environment Mostly relate to radiation safety for theatre personnel and patient

Plan saved, exported to TCS and printedPlan printed from TCSChecked against primary source with physicistRoom checklist completed by two peoplePatient monitored on CCTV intercom and slave from anaesthetic machine BT, Physicist, Rad Onc and Anaesthetist all in treatment control room

At end of treatment, the medical physicist surveys the room to ensure the source has retracted into the afterloader unit

This is signed for on check sheet

Also keep record of treatment in log book -again paper because brachytherapy unit not linked to Record and Verify System

These processes are performed and completed each fraction

BRACHYTHERAPY with Radioiwwpi-i

IRIDIUM 192 HIGH DOSE RATE TANDEM & OVOIDS

ittEscmmoNS and diagrams

@ I -2-fx per weeXTumourTandem

Pictures coutesy of ■ Ivia VanDiyck

SUM MARY patient Am received — I Using Tandem & Ovoid applicators. Isotope ■■

Quality Control measures inbrachytherapy

Records of treatment - patient file log book

t-n3

q-13 2.3

j zy! ;

• Record of treatment• Treatment sheet filed in patient's history• Log book -papersystem as brachytherapy not linked Record and Verify System• Image treatment sheet• Image log book

Quality Control measures in brachytherapy

a/p Late Eff.= a/p Early Eff.=

Dose/Fraction for Equivalence Calc (r)=

310

2

Dose Modifying Factor (DMF) for HDR =

EBRT Dose/fx (Gy)=0.72

Total EBRT Dose(Gy) @

2 Gy/fx# of HDRfractions

HDRdoseGy/fx

Equiv. Dose for tumor

effects

Equiv. Dose (late effects no

DMF)

Equiv. Dose (late effects with DMF)

40 4 7.3 82.1 100.2 73.240 4 5.1 65.7 73.0 58.840 4 3.5 55.8 58.2 50.740 4 4.7 63.0 69.0 56.640 4 8.8 95.1 123.1 85.1

Total dose reporting in treatment sheetProspective data base contains:

Ultrasound images MRI/US measurements

Dosimetry details

Target volume Point A ICRU38 Bladder ICRU38 Rectum

Vag Mucosa

• Treatment finalised• Dose reporting total dose to Target• Point A• ICRU38 bladder• ICRU 38 rectum• Vaginal mucosa• Brachytherapy contribution to nodal boosts• US images saved to prospective database• MRI/US measurements saved to prospective database• Dosimetry details saved to prospective data base

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IAEA

iTPS acceptance testing_____1) Source specification

-model (source type, shape dimensions, material), nuclide, half-life time, quality (gamma energy), reference-date and strength of the source

2) Validation of dose distributionused algorithm-^point source complex geometryradioactive decay (if half-life time is short) during the irradiation

3) Reconstruction (source path)radiographs (reconstruction box or jig), stereo-shift, C-arm, US, CT or MRI

4) Plan evaluationdose distribution (point-dose, isodose-iines) in several orientations (trans., sag., cor.) normalization (dose- or reference- point, F-factor, volume) switch between relative and absolute modus (% versus Gy) symmetry of dose distribution (E.g. vaginal cylinder)Dose Volume Histogram (Vol., boolean operations)

IAEA

lr-192: Different Source Models

Model: Active length Activediameter Total diameter

Distance from active edge to

tip of the source

Encapsulation

MicroSelectronNucletron 3.5 0.6 1.1 0.35 Stainless steel

classicMicroSelectron

Nucletron 3.6 0.65 0.9 0.2 Stainless steelnew design

VariSource 10 0.35 0.61 1 Ni-Ti

Varian 5 0.34 0.59 1 Ni-Ti

Buehler 1.3 1 1.6 1 Stainless steel

Gamma Med 12i 3.5 0.6 1.1 0.86 Stainless steel

Gamma Med Plus 3.5 0.6 0.9 0.62 Stainless steel

BEBIG 3.5 0.6 1.0 0.9 Stainless steel

Table reproduced from ESTRO Booklet No. 8, 2004 with permission courtesy of ESTRO

IAEA

Where to find the Datadm ESTR0*

1^ IUO»OTHf tAFt 4 OWCOtOCY

Dose Calculation for Photon-Emitting Brachytherapy Sources

with Average Energy Higher than 50 keV: Full Report of the AAPM and ESTRO

Report of the

High Energy Brachytherapy Source Dosimetry (HEBD) Working Group

August 2012

DISCLAIMER: This publication is based on sources and information belies ed to be reliable, but the AAPM. the authors, and the editors disclaim any warranty or liability based on or relating to the contents of this publication.

The AAPM does not endorse any products, manufacturers, or suppliers. Nothing in this publication should be interpreted as imply ing such endorsement.

© 2012 by American Association of Physicists in Medicine

IAEA

Specific information for your Source Model can be found on ESTRO homepage or directly from the vendor

TG43 BT DOSIMETRIC PARAMETERS FOR Co-60

Co-60 Sources

MANUFACTURER SOURCE MODEL

Eckert a Ziegler Straiten- und Medizintechnik AC, Multisource® Co-60 HDR GK60M21

Multisource® Co-60 HDR CO0.A86

Shimazdu Corporation, Japan Ralstron HDR Type 1

Ralstron HDR Type 2

Ralstron HDR Type 3

Page last updated on 29th February 2008

Radionucleotides

Co-60

Cs-131

Cs-137

1-125

Ir-192 HDR

lr-192 LDR Seeds

Ir-192 LDR Wires

lr-192 PDR

Ir-192 Applicators

Pd-103

Yb-169

Notes and Contact

Dosimetric Parameter Home Page

E TG43 dataset is given for a source type NOT for the nuclide

TG43 formalism:

b(r,ff)=St\ g(r)anisotropy

functionair kerma strength geometry functionradial dose

dose rate constant function

IAEA

TPS acceptance testing1) Source specification


2) Validation of dose distributionused algorithm point source complex geometryradioactive decay (if half-life time is short) during the irradiation



IAEA

Validation of dose distribution

Point source

y z -x (from table)time [s]: 10

planned source strength [U]: 43586,1 ref.date: 1.9.2008,13:00

IAEA D(r,0) = Sk AValidation of dose distribution

G(r,0)GM)

g(r) F(r,0)

complex geometry

y*

z X->

-from table (TG43)

Source Coordinates D(x,y) [cGy/h.U] D [cGy]x [mm] y [mm] z [mm]1 1,06066 1,06066 0,00000 0,49700 60,173032 -1,06066 1,06066 0,00000 0,49700 60,173033 -1,06066 -1,06066 0,00000 0,49700 60,173034 1,06066 -1,06066 0,00000 0,49700 60,17303

c2=a2+b2 -> for c=1.5 (which is listed i

Total dose in dose point [cGy]: 240,69 Time per source [s]: 10

planned source strength [U]: 43586,1

Total dose in dose point [cGy] calc, by TPS: 239| Difference: -0,70%~|

frorrHable (TG43)

Source Coordinates Theta (°) r(cm) Gl(x,z) F (r,theta) g(r) D [cGy]x [mm] y [mm] z [mm]

1 0,96 0,00 1,15 50 1,500 0,446 0,972 1,002 58,292 -0,96 0,00 1,15 130 1,500 0,447 0,971 1,002 58,383 -0,96 0,00 -1,15 50 1,500 0,447 0,972 1,002 58,444 0,96 0,00 -1,15 130 1,500 0,447 0,971 1,002 58,38

Total dose in dose point [cGy]: 233,49 Time per source [s]: 10

planned source strength [U]: 43586,1 dose rate constant [cGy/hU]: 1,109

source length L [mm]: 0,35

feX->

Total dose in dose point [cGy] calc, by TPS:Difference:

2350,65%

G,.('•>*) =0 = 0,x

IAEA



2) Validation of dose distributionused algorithmpoint source complex geometryradioactive decay (if half-life time is short) during the irradiation


4) Plan evaluationdose distribution (point-dose, isodose-iines) in several orientations (trans., sag., cor.) normalization (dose- or reference- point, F-factor, volume) switch between relative and absolute modus (% versus Gy) symmetry of dose distribution (E.g. vaginal cylinder)Dose Volume Histogramme (Vol., boolean operations,

Reconstruction (source path)radiographs (reconstruction box or jig), stereo-shift, C-arm, US, CT or MRI


Source positions from the template in the TPS 1,12 ,23 and 34 are compared with real irradiated positions on the film

IAEA

Quality Control in applicator reconstruction

IAEA

Quality Control in applicator reconstruction

QC - reconstruction standardloadingpattern

. o

»"

. o

9•

3

=

•SI•Si

|27]

1

i

ES

ffl

wrong source path reconstruction

correct source path reconstruction

IAEA



2) Validation of dose distributionused algorithmpoint source complex geometryradioactive decay (if half-life time is short) during the irradiation



Accuracy of volume and DVH parameters determined with different brachytherapy trpatmpnt nlannino W<;tpm<;

aa

Rh ids

Fig. 2. Dose distribution of treatment plan 1. The dose values for F 0O ioc> related to the most exposed 0.1cm3 are ~410% for the large (■ cylinder and ~830% for the cone. The D^c represents the minimum „____________________ 122__________________ M

dose in the large cylinder and cone covered by the —350% and-540% isodose, respectively, (a) Transaxial view through the center Fig. 1 Cut view (a) and top view (b) of the phantom used to

i, ^vXmT <b> Coronal VteW thr0U8h the central axes °f CT and MR ima«e a smal1 cy*inder 4 02 a"3- alarge cylinder with 56.54 cm3, and a truncated cone with 63.02 cm3.

KIRISITS, C., et al.. Accuracy of volume and DVH parameters determined with different brachytherapy treatment planning systems, Radiother Oncol 84 (2007) 290-297, copyright Elsevier, reproduced with permission

Accuracy of volume and DVH parameters determined with different brachytherapy treatment planning systems

b

Rh

Fig. 3. Deviations of volume calculations for 2 mm CT (a), 4 mm CT (b), 4 mm spiral CT (c), and 5 mm MRI (d) datasets. Differences calculated by each treatment planning system are related to the mean value for all systems. For each structure one relative standard deviation (SD) and the difference of this mean value to the true volume (offset) are given. This figure compares differences of the 3D reconstruction and calculation algorithms for the different planning systems and not the uncertainties in obtaining the true volume, which are influenced by the imaging technique and individual scan geometry.

KIRISITS, C., et al.. Accuracy of volume and DVH parameters determined with different brachytherapy treatment planning systems, Radiother Oncol 84 (2007) 290-297, copyright Elsevier, reproduced with permission

ids

LiteratureAAPM Task group recommendations• TG43/U1 Brachytherapy Source Dosimetry• TG53 Treatment Planning QA• TG56 Brachytherapy Physics Code of Practice• TG64 Permanent Prostate Seed Implants• TG40 Comprehensive QA for Radiation Oncology• TG100 Update TG40, in committee, may address treatment planning

systems as equipment

Books• Achieving Quality in Brachytherapy, Thomadsen ISBN-13: 978-07503-055409

• The Physics of Modern Brachytherapy for Oncology, Baltas, Sakelliou, ZamboglouISBN 0-7503-0708-0

Follow your National Standard• 0NORM S5296 (Treatment Planning system QA) Austrian standard

IAEA

Bibliography

• AWUNOR, O. A., DIXON, B., WALKER, C., Direct reconstruction and associated uncertainties of 192lr source dwell positions in ring applicators using gafchromic film in the treatment planning of HDR brachytherapy cervix patients, Phys. Med. Biol. 58 (2013) 3207-3225.

• BALTAS, D., SAKELLIOU, L., ZAMBOGLOU, N., The Physics of Modern Brachytherapy for Oncology, CRC Press, Boca Raton (2006).

• BERNDT, A., RICKEY, D. W„ RATHEE, S„ BEWS, J„ Size and positioning reproducibility of an 192lr brachytherapy stepping source, Med. Phys. 27 (2000) 129-131.

• CANADIAN ASSOCIATION OF PROVINCIAL CANCER AGENCIES, Brachytherapy Remote Afterloaders, CAPCA Quality Control Standards, CAPCA (2006).

• FRAASS, B., et al., American Association of Physicists in Medicine Radiation Therapy Committee Task Group 53: quality assurance for clinical radiotherapy treatment planning, Med. Phys. 25 (1998) 1773- 1829.

• INTERNATIONAL ATOMIC ENERGY AGENCY, Setting Up a Radiotherapy Programme: Clinical, Medical Physics, Radiation Protection and Safety Aspects, IAEA, Vienna (2008).

• INTERNATIONAL ATOMIC ENERGY AGENCY, Commissioning and Quality Assurance of Computerized Planning Systems for Radiation Treatment of Cancer, Technical Reports Series No. 430, IAEA, Vienna (2004).

• INTERNATIONAL COMMISSION ON RADIATION UNITS AND MEASUREMENTS, Dose and Volume Specification for Reporting Intracavitary Therapy in Gynecology, ICRU Rep. 38, ICRU, Bethesda, MD (1985).

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Bibliography

• JAYARAMAN, S., LANZL, L. H., AGARWAL, S. K., An overview of errors in line source dosimetry for gamma-ray brachytherapy, Med. Phys. 10 (1983) 871-875.

• KIRISITS, C., et al., Accuracy of volume and DVH parameters determined with different brachytherapy treatment planning systems, Radiother Oncol 84 (2007) 290-297.

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IAEA

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