Evaluation of build-up dose from 6 MV X-rays under pelvic and abdominal patient immobilisation devices

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

15 Scopus Citations
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Detail(s)

Original languageEnglish
Pages (from-to)235-238
Journal / PublicationRadiation Measurements
Volume35
Issue number3
Publication statusPublished - 2002

Abstract

The use of pelvic and abdominal immobilisation devices in radiotherapy is required for accurate positioning and repositioning of patients during their fractionated treatment delivered normally over a period of 5-6 weeks. 6 MV X-rays produced by a medical linear accelerator have a skin sparing effect whereby the skin dose delivered is considerably less than that received by the tumour. The treatment through a vacuum compressed immobilisation device (Vacbag) however increases the dose delivered to the skin by interactions of the X-rays within the Vacbag material. For example, the basal layer doses increased from 16% for an open field to 52% of maximum with a bag thickness of 2.5 cm for a 10 cm × 10 cm field at 6 MV X-ray energy. At the same field size the dermal skin layer (1 mm depth) doses increased from 44% (no bag) to 60% for a bag thickness of 2.5 cm at 6 MV X-rays. The Vacbag should be placed outside the treatment field whenever possible to keep skin dose to a minimum level. © 2002 Published by Elsevier Science Ltd.

Research Area(s)

  • Patient immobilisation, Radiotherapy, Skin dose, Vacbag