Detector system dose verification comparisons for arc therapy: couch vs. gantry mount.

The aim of this study was to assess the performance of a gantry-mounted detector system and a couch set detector system using a systematic multileaf collimator positional error manually introduced for volumetric-modulated arc therapy. Four head and neck and esophagus VMAT plans were evaluated by measurement using an electronic portal imaging device and an ion chamber array. Each plan was copied and duplicated with a 1 mm systematic MLC positional error in the left leaf bank.

Computation of relative dose distribution and effective transmission around a shielded vaginal cylinder with 192Ir HDR source using MCNP4B.

The present work is primarily focused on the estimation of relative dose distribution and effective transmission around a shielded vaginal cylinder with an 192Ir source using the Monte Carlo technique. The MCNP4B code was used to evaluate the dose distribution around a tungsten shielded vaginal cylinder as a function of thickness and angular shielding. The dose distribution and effective transmission of 192Ir by 0.