Advanced Physics for Brachytherapy 2018

Example: overview of optimum level of uncertainties for different clinical sites ( BRAPHYQS AAPM guidelines 2014, Radiother Oncol 110)

HDR 192 Ir gyn vaginal

HDR 192 Ir ic cervix

HDR 192 Ir breast balloon*

LDR 125 I prostate

HDR 192 Ir prostate

BT application

Source strength

2% 2% 2% 3% 2%

Treatment planning

3% 3% 3% 4% 3%

Medium dosimetric corrections

1% 1% 3% 5% 1%

Dose delivery including registration of applicator geometry to anatomy

5% 4% 7% 4%** 2%

Interfraction/Intrafraction changes

5% 11% 7% 7% 2%

…

Total dosimetric uncertainty (for one fraction)

~8% ~12% ~13% ~11% ~5%

*additional scatter dosimetric corrections (skin, surface): 7% ** inter-seed attenuation *** additional imaging and planning based uncertainties, see original publication