Advanced Physics for Brachytherapy 2018

The limitations

• Homogeneous water medium assumed

• Full scatter condition assumed

➢ 5 cm beyond the last position of interest for low energy seed (15 cm geometry) ➢ 20 cm beyond the last position of interest for E > 50 keV (40 cm radius geometry)

• No electrons (Dose vs Kerma)

➢ Dose may not be related to photon fluence close to the source (e.g. 60 Co)

• Full 3D source geometry not taken into account

➢

Close to the source

➢

Extended line sources, …

➢

Shielded applicators or directional sources