Synthetic diamonds as in vivo radiation detectors

Synthetic diamonds with controlled amounts of impurity atoms can be manufactured so that, as thermoluminescent dosimeters, they can be made to have sensitivities at least as good as presently available commercial thermoluminescent dosimeters. They also exhibit, for radiations normally found in therapy situations, a linearity of response that extends from less than 0.01 Gy (1 rad) to over 10 Gy (1000 rad). Their physical size and form, crystals which can have volumes of less than 1 mm3, make them ideal candidates for in vivo monitoring of radiation fields, particularly electron fields where high-resolution measurements are essential for accurate isodose line determinations. Aspects of dose response from gamma-ray beams in relation to the type and concentrations of the impurity atoms within the diamond are discussed, and some experimental values for gamma, x-ray, and electron beams are presented.