Pulsed brachytherapy: a modelled consideration of repair parameter uncertainties and their influence on treatment duration extension and daytime-only "block-schemes".

Objectives: The radiobiological modelling of all types of protracted brachytherapy is susceptible to uncertainties in the values of tissue repair parameters. Although this effect has been explored for many aspects of pulsed brachytherapy (PB), it is usually considered within the constraint of a fixed brachytherapy treatment time. Here the impact of repair parameter uncertainty is assessed for PB treatments of variable duration.

Electron dosimetry of angular fields.

Shaping electron fields through the use of lead cut-outs may result in there being acute angles in part of the field. Using both experimental techniques and EGSnrc Monte Carlo simulations an investigation was carried out to determine the dosimetric consequences of this. Measurements were made to investigate how the field dose was related to the angle between adjacent sides in the cut-outs.

The dose distribution of low dose rate Cs-137 in intracavitary brachytherapy: comparison of Monte Carlo simulation, treatment planning calculation and polymer gel measurement.

In this study, the dose distribution delivered by low dose rate Cs-137 brachytherapy sources was investigated using Monte Carlo (MC) techniques and polymer gel dosimetry. The results obtained were compared with a commercial treatment planning system (TPS). The 20 mm and the 30 mm diameter Selectron vaginal applicator set (Nucletron) were used for this study.

Treatment accuracy of fractionated stereotactic radiotherapy.

Background And Purpose: To assess the geometric accuracy of the delivery of fractionated stereotactic radiotherapy (FSRT) for brain tumours using the Gill-Thomas-Cosman (GTC) relocatable frame. Accuracy of treatment delivery was measured via portal images acquired with an amorphous silicon based electronic portal imager (EPI). Results were used to assess the existing verification process and to review the current margins used for the expansion of clinical target volume (CTV) to planning target volume (PTV).

Consumer preferences for general practitioner services.

This study focuses on segmenting the market for General Practitioner services in a regional setting. Using factor analysis, five main service attributes are identified. These are clear communication, ongoing doctor-patient relationship, same gender as the patient, provides advice to the patient, and empowers the patient to make his/her own decisions.

Influence of a vac-fix immobilization device on the accuracy of patient positioning during routine breast radiotherapy.

Continued use of basic planning and treatment techniques, in contrast to the improved methods implemented at many other anatomical sites, has emphasized the need for improved breast dosimetry. Any future technique delivering a superior three-dimensional dose distribution will be of maximum benefit if set-up errors are minimized. To determine the influence of vacuum moulded bag (vac-fix) immobilization on routine breast radiotherapy, 17 patients received half their radiotherapy fractions using our standard breast board technique and half using a vac-fix device positioned on the breast board.