Increasing cancer treatment efficacy using 3D brachytherapy

Short Name: Brachytherapy, Project Number: T2.J06
Brachytherapy (BT) is a radiotherapy technique in which small encapsulated radioactive sources are placed inside or in close proximity to the treatment volume, delivering a high dose to the tumour at small distances while sparing the surrounding tissue. About 100 000 patients per year are treated in the European area with BT (about 10% of radiotherapy treatments).

The project established a more accurate metrological basis for the dosimetry of radioactive sources used in the clinic for Brachytherapy across Europe. It responds to the need for traceability of absorbed dose measurements of BT radiation sources to absorbed dose to water primary standards. The absorbed dose to water, DW, is the quantity of interest for dosimetry in radiotherapy, but no absorbed-dose-to-water primary standards were available for dosimetry of BT. The procedures to determine the absorbed dose imparted to the patient based on measurements traceable to the existing air kerma standards are affected by an uncertainty higher than the limit recommended by the IAEA dosimetry protocol (IAEA-TRS 398, 2000) to assure the effectiveness of radiotherapy treatments.

A significant fraction of this uncertainty was due to a lack of metrology. The ultimate goal of the "Brachytherapy" project was to develop methods and standards for the direct measurement of the quantity Dw in Brachytherapy dosimetry with a reduced uncertainty in the dose delivered to the patient (target value less than 5% (k=1) at clinical level).