5. DOSE MONITORING SYSTEM IN TOTAL BODY IRRADIATION

Abstract

We discussed suitable X-rays energy, dose monitorring system and other problems in the total body irradiation. As the results, 1) X-rays energy : 10MV X-rays is better than 4MV X-rays for flatness on central axis, although 4MV X-rays is better than 10MV X-rays for large field and the short surface axis distance (SAD). A dose distribution of 4MV X-rays is improved by the four field technique, of anterior-posterior and lateral opposed fields. 2) Phantom which is as large as a human body is necessary for the dose measurment of large field. 3) Dose monitoring : Standard point dose in the pelvis must be kept within 99.5±3.4% for expected dose. 4) Dose monitoring system : This system is necessary for the dose evaluation on the mid-line of the body. The mid-line dose is influenced by the flatness in the field and compensating material.