SOLED STATE DETECTORS FOR QUALITY ASSURANCE IN BRACHYTHERAPY

Because of the low energy of photon or beta radioactive sources currently used for modem techniques of brachytherapy, and the high dose gradient existing around them, the dosimeters to be used for quality controls of the sources or absorbed dose measurements should have special characteristics such as an accurate and reproducible response, a low dose response dependence as a function of energy, a high sensitivity under a small volume, a response independent of the dose-rate, etc. Commercial solid state detectors, such as diodes, MOSFETs, EPR-alanine, Gafchromic films, plastic scintillators and radiothermoluminescent (RTL) dosimeters, can be interesting in the concerned field. After a brief reminder of their principle, a review of their dosimetric advantages and disadvantages is presented. A selection of detectors the best suited for brachytherapy with examples of use for quality assurance controls or in-vivo dosimetry is also presented.