RADIATION PROTECTION IN RADIOTHERAPY

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RADIATION PROTECTION IN RADIOTHERAPY
IAEA Training Material on Radiation Protection in
Radiotherapy

• Part 11 Brachytherapy
• PRACTICAL EXERCISE

IAEA Post Graduate Educational Course Radiation
Protection and Safe Use of Radiation Sources
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Objectives

• To be familiar with the brachytherapy process
• To be able to discuss methods for brachytherapy
  planning and dosimetry
• To understand the optimization of dose delivery
  to the target by choosing appropriate isotopes
  and delivery techniques
• To understand the implications of the above for
  radiation safety

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Part 11 Good Practice in Brachytherapy
IAEA Training Material on Radiation Protection in
Radiotherapy

• Practical 1 QA for HDR brachytherapy

IAEA Post Graduate Educational Course Radiation
Protection and Safe Use of Radiation Sources
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High Dose Rate Brachytherapy

• Most modern brachytherapy is delivered using HDR
• Outpatient procedure
• Optimization possible

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Optimization of dose distribution

• Can be achieved by altering the dwell times in
  all positions
• High activity source (gt30GBq 192-Ir)
• Complex movement

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Contents Objective

• Quality assurance of the brachytherapy unit
• Source
• Movement/localization
• Timers
• Associated equipment
• Radiation monitors/safety equipment
• Be able to perform tests for the above

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Check of the source

• Activity
• Well chamber
• Phantom
• In-air jig
• Integrity of the source
• Wipe test typically performed by the company

Courtesy Nucletron
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Additional issues

• Ensure calibration of dosimetric devices is
  traceable to appropriate standard
• Verify decay correction in treatment planning

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Verification of movement

• Check new source can move through all applicators
  and catheters in use (no rough edges, no
  difference in size)
• Check dummy source (used for localization of the
  applicators and for motion test prior to
  treatment) and real source have identical
  geometry (if applicable)

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Check positioning accuracy

• Verify different distances
• jigs available
• may be possible via video camera
• film allows to obtain permanent record and use
  different applicators

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Verification of source movement

• Measurement jig
• Film cassette for autoradiograph

MDS Nordion
Measurement jig allows introduction of active
source and dummy
Nucletron
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Associated issues

• Determine correct length of needles and catheters
• Check diagnostic X Ray equipment for distortion
• Verify digitizer and printer scale and dimensions

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Timer

• Both independent timers MUST be checked

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Associated equipment

• Safety Interlocks
• Mobile shielding
• Emergency safe
• Manual source retraction
• Compare hard copies and treatment records are
  correct

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Check all applicators, templates and spacers in
use for integrity
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Radiation monitors

• Working?
• Accurate reading?
• Check sources?
• Traceable calibration?
• Any interlocks or alarms connected working?

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Questions?

• Lets get started...