EPR DOSIMETRY WITH ALANINE FOR TOTAL BODY IRRADIATION USING AN ANTHROPOMORPHIC PHANTOM

Abstract

The Total Body Irradiation (TBI) is a radiation therapy technique widely used in clinical hemato-oncological treatment of patients that underwent bone marrow transplantation or peripheral stem cell transplantation. Typically, the administration of TBI treatment provides irradiations in 3 consecu-tive days with a double daily fractionation, although other dose fractionation modes have been widely adopted in the clinic procedures. Although this tech-nique allows to irradiate the whole body from head to toes, it has some limitations such as the lack of homogeneity of the dose distribution (which can show varia-tions of 20% in the different areas), irradiation of critical organs such as lungs, liver, intestine and eyeballs that receive a dose comparable to the nominal one and require appropriate shielding and a proper evaluation of the dose absorbed by them. The positive outcome of this type of radiation therapy is closely related to a precise and accurate measurement of dose distribution delivered to the patient in the various body districts. In this work the dose administered in a anthropo-morphic (RANDO) phantom during TBI treatments was evaluated by means EPR dosimetry with alanine. The estimate of the dose was carried out at various points inside the phantom that has been irradiated with a clinical TBI beam configuration by applying a proper shielding provided for the lungs. Doses measured through EPR were compared with those measured with a semiconductor diode