Validation of the modified radiosurgery-based arteriovenous malformation score in a linear accelerator radiosurgery experience in Hong Kong.

The modified radiosurgery-based arteriovenous malformation (AVM) score (modified AVM score or Pollock-Flickinger AVM score [PFAS]) is a simplified grading system developed to predict outcome after gamma knife radiosurgery for cerebral AVM. The purpose of this study was to test the PFAS in a cohort of patients managed with linear accelerator (LINAC) radiosurgery. We analyzed 70 consecutive patients with cerebral AVM treated with LINAC radiosurgery in Hong Kong.

The roles of multileaf collimators and micro-multileaf collimators in conformal and conventional nasopharyngeal carcinoma radiotherapy treatments.

The purpose of this work is to study the efficacy and limitations of using standard multileaf collimators (MLCs) and micro-multileaf collimators (mMLCs) in the treatment of nasopharyngeal carcinoma (NPC) by conventional and conformal radiotherapy techniques. The penumbra characteristics of MLC, mMLC, and customized block collimated beams are measured with respect to leaf edge angle, beam energy, treatment depth, and field size and compared with those generated by a commercial three-dimensional planning computer system. Upon verification of the planning system, it is used to evaluate the treatment plans generated with these beam shapers for conventional and conformal NPC treatments.

Partition model for estimating radiation doses from yttrium-90 microspheres in treating hepatic tumours.

A uniform distribution of yttrium-90 (90Y) microspheres throughout the entire liver has always been assumed for dose calculation in treating hepatic tumours. A simple mathematical model was formulated which allows estimation of the activities of a therapeutic dose of 90Y microspheres partitioned between the lungs, the tumour and the normal liver, and hence the radiation doses to them. The doses to the tumour and normal liver were verified by intra-operative direct beta-probing.

Perineal Paget's disease: effective treatment with fractionated high dose rate brachytherapy.

A patient with perineal extramammary Paget's disease is described. He was treated successfully with fractionated high dose rate brachytherapy.