ARE MOVING JUNCTIONS IN CRANIOSPINAL IRRADIATION FOR MEDULLOBLASTOMA REALLY NECESSARY

The case notes of 35 patients treated for medulloblastoma using a stan dard technique of craniospinal irradiation (CSI) from 1978 to 1992 wer e reviewed. Two large opposed lateral fields to the whole brain and an orthogonal posterior spinal field were used. The position of the junc tion between the fields was constant throughout treatment with no feat hering and no gap. We present our results, review the literature and d iscuss the need for feathering. The junction between the cranial and s pinal fields produces an area of dose inhomogeneity but the clinical s ignificance of this and the effect of feathering is uncertain.