Main dosimeter properties

A variety of detector types with different design for intensity measurements of ionizing radiation is available on the market. Comparisons among them and positioning of new products compared to them, can be conducted on the basis of the analysis of the below listed characteristics (Main source: Izewska J., Rajan G., 2005. “Radiation dosimeters,” Document IAEA 08/2005, STI/PUB/1196, Textbook, Chapter3, 71–99.)

High Precision and accuracy. Ability of the dosimeter to provide reproducible measurements (precision) and that do not deviate from the true value (accuracy).

Linear response. Capacity of the dosimeter to provide a measure that has a linear relationship with the dose administered or with the energy of the incident radiation. No corrections to the signal are needed.

High spatial resolutionThe high spatial resolution of a dosimeter means possibility of spatially accurate measuring the dose of radiation, with possible applications in microdosimetry.

Real Time answer. Capacity of the dosimeter to provide the given reading in real time, useful for making corrective actions during irradiation.

Absolute measurement of dose. Ability of the dosimeter to measure absorbed dose in Gray (Gy) after appropriate intercalibration with primary standard of reference.

In vivo measure. Ability to evaluate the magnitude of the absorbed dose to the patient in comparison with the dose prescribed to the patient in the treatment plan, placing the dosimeter on the skin of the patient or implanting it (e.g. in natural cavities …). Indeed, there is a difference between the input dose to the tissues of the patient and the output one, while the body of the patient may differ in shape and dimensions with respect to the theoretical geometry calculated from the Treatment Planning System (TPS). In vivo measures may allow to correct errors made, for example, in the parameters of irradiation or in the positioning of the patient.

Independence to the environmental conditions. The main are: SVWT (sensitivity variation with temperature), the dosimeter designed to be invariant to the range of temperatures typically employed (20 – 37 °C approximately); independence to the atmospheric pressure; stability in a wide range of relative humidity.