radiation protection in radiotherapy part 2: radiation physics practical exercise iaea training...
TRANSCRIPT
RADIATION PROTECTION IN RADIATION PROTECTION IN RADIOTHERAPYRADIOTHERAPY
Part 2: Radiation PhysicsPart 2: Radiation Physics
PRACTICAL EXERCISEPRACTICAL EXERCISE
IAEA Training Material on Radiation Protection in Radiotherapy
Part 2, Practical 1 2Radiotherapy
ObjectivesObjectives
To be familiar with different types of ionizing To be familiar with different types of ionizing radiationradiation
To understand the most important interaction To understand the most important interaction processes between radiation and matterprocesses between radiation and matter
To be able to use and understand all basic To be able to use and understand all basic radiation quantitiesradiation quantities
To have a basic understanding of the means To have a basic understanding of the means of radiation detectionof radiation detection
Part 2: Part 2: Radiation PhysicsRadiation Physics
Practical 1: Inverse square lawPractical 1: Inverse square law
IAEA Training Material on Radiation Protection in Radiotherapy
Part 2, Practical 1 4Radiotherapy
Contents + ObjectiveContents + Objective
Learn about the importance of distance Learn about the importance of distance as a means to reduce radiation as a means to reduce radiation exposureexposure
Perform an experiment to demonstrate Perform an experiment to demonstrate thisthis
Part 2, Practical 1 5Radiotherapy
What Minimum Equipment is What Minimum Equipment is Needed?Needed? Radiation sourceRadiation source Radiation detectorRadiation detector Tape distance measureTape distance measure Graph paperGraph paper
Part 2, Practical 1 6Radiotherapy
Radiation sourceRadiation source Ideal a 60-Co source Ideal a 60-Co source
for teaching (activity for teaching (activity <100kBq)<100kBq)
Should be high Should be high energy gamma to energy gamma to minimize attenuationminimize attenuation
Some experiments Some experiments can also be can also be performed with performed with brachytherapy sourcebrachytherapy source
Part 2, Practical 1 7Radiotherapy
Radiation detectorRadiation detector
Best a Geiger Best a Geiger counter with window counter with window thick enough to be thick enough to be mostly sensitive to mostly sensitive to gamma radiationgamma radiation
A survey meter may A survey meter may also be suitablealso be suitable
Part 2, Practical 1 8Radiotherapy
Record readings at different Record readings at different distancesdistances
distance
sourcedetector
Part 2, Practical 1 9Radiotherapy
Record and Record and plot dataplot data
Inverse Square Law Calculation SheetDate:Instrument:Source:Activity:Calibration date:
Distance(m) Reading
Instrument Relative to 1m0.10.20.5
11.5
23
0
20
40
60
80
100
0 0.5 1 1.5 2 2.5
distance from source (m)
rela
tive
det
ecto
r re
adin
g
Part 2, Practical 1 10Radiotherapy
Important consequencesImportant consequences
Distance is a powerful way to reduce Distance is a powerful way to reduce exposureexposure
Practical implications in radiotherapy:Practical implications in radiotherapy: use long tweezers to handle sources in use long tweezers to handle sources in
brachytherapybrachytherapy a long maze can reduce shielding a long maze can reduce shielding
requirements for doors significantlyrequirements for doors significantly
Part 2, Practical 1 11Radiotherapy
AcknowledgementAcknowledgement
Photos from Leybold-Didaktik web page: Photos from Leybold-Didaktik web page: www.leybold.dewww.leybold.de
Part 2, Practical 1 12Radiotherapy
Questions?Questions?
Let’s get started...Let’s get started...