Monte Carlo dosimetry for the Papillon P50 contact radiotherapy and IORT device.

Contact radiotherapy uses small field sizes and very short SSDs to deliver low-energy X-rays very close to the position of a tumour. We present a Monte Carlo simulation of the Papillon contact radiotherapy machine, and in particular the backscatter factor, to investigate whether the factors given in current Codes of practice for kV dosimetry remain valid under these conditions.

A separated primary and scatter model for independent dose calculation of intensity modulated radiotherapy.

Background And Purpose: Independent checking of beam monitor units is an essential step in the preparation of any radiotherapy plan. The present work describes a simple model for calculating a point dose from an arbitrary number of irregular, asymmetric fields, typical of beam segments used for IMRT.

Materials And Methods: Primary and scatter dose contributions were separated using a two-parameter exponential fit to measured beam data, from which differential scatter is determined.

Aortic root abscess. Initial experience using magnetic resonance imaging.

The detection of aortic root abscess by magnetic resonance imaging has not been described previously. We report a patient with an aortic root abscess that was successfully diagnosed by magnetic resonance imaging and echocardiography. Computed tomography failed to detect the abscess.