Dose 2016

Phantom for plan QA: measurement vs calculation

Dose determination in phantom

Calculations of dose in phantom

Formalism to derive dose to water from from ionisation measurements in PMMA

How accurate are the HU-density conversions for plastic phantoms?

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w

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[

]

µ

Would it be better to create a virtual phantom with the density of PMMA?

=

clin w

clin PMMA D D

scat

en

CF

PMMA

w

cal

→

ρ

PMMA

cal

How does the TPSs handle materials different from water?

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PMMA

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air clin PMMA S N k M D ion

=

clin PMMA

wall p p

Does the TPS calculates dose to PMMA in PMMA or dose to water in PMMA?

repl

ρ

air

cal

Chamber and medium specific perturbation factors are for the calibration geometry and not the clinical field

Ma et al, PMB 48 (2003) 561-572