Prescribed and Measured Dose Differences for an AP-PA TBI Protocol with Compensation Filter and Ergonomic Patient...

A treatment scheme is presented for clinical applications of total body radiation using 6 MV photons.

The two-field technique, anteroposterior (AP) and posteroanterior (PA), was applied. In vivo dose verification with TLD-100 dosimeters was developed during the first treatment sessions. Dosimetry was performed in several anatomical regions such as head, shoulder, thorax, abdomen, hip, thigh, knee, and ankle in 13 patients as preconditioning for bone marrow transplantation. A prescribed dose of 100 cGy was considered at the level of the patient's coronal plane. Values with least differences between measured and prescribed dose were obtained for the shoulder.

Standard deviation percentages of 0.3% and 2.6% were recorded between these doses for AP and PA, respectively. There were larger differences for other contours. In general, a measured dose less than the prescribed dose was observed in all the contours.

Differences between prescribed and measured doses showed in this study can contribute to a required understanding about the accurate doses in AP-PA total body irradiation (TBI) treatments.