Hippocampus Avoidance Whole-brain Radiation Therapy: A Practical Intensity-modulated Radiation Therapy Planning and Delivery Approach to RTOG 0933.

Purpose: The goal of this work was to develop a more practical technique to meet the requirements of the Radiation Therapy Oncology Group (RTOG) 0933 protocol for sparing the hippocampus while irradiating the whole brain. Whole-brain radiation therapy (WBRT) has been linked to a decrease in neurocognitive function and increase in memory loss leading to lower quality of life for patients. Hippocampus avoidance (HA) WBRT may help to mitigate these issues by delaying the decline in neurocognitive function.

Planning target volume margin evaluation and critical structure sparing for rectal cancer patients treated prone on a bellyboard.

Aims: To calculate a planning target volume (PTV) margin that would account for inter-fractional systematic and random clinical target volume positional errors for patients treated prone on a recently available couch top bellyboard and to evaluate potential critical structure dose reduction using intensity-modulated radiotherapy (IMRT) techniques.

Materials And Methods: Twenty-four patients (12 men and 12 women) were included in this study, all treated on a commercial bellyboard. Cone beam computed tomography (CBCT) data were acquired once every five fractions for a total of five images per patient.