Abstract：
:Total scalp irradiation is a treatment technique used for a variety of superficial malignancies. Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published work has shown the TomoTherapy planning system to overestimate the superficial dose. In this study, the superficial doses for a helical tomotherapy total scalp irradiation have been measured on an anthropomorphic phantom using radiochromic and radiographic film as well as a new skin dosimeter, the MOSkin. The superficial dose was found to be accurately calculated by the Tomo-Therapy planning system. This is in contrast to recent reports, probably due to a combination of the smaller dose grid resolution used in planning and this particular treatment primarily consisting of beamlets tangential to the scalp. The superficial dose was found to increase from 33.6 to 41.2 Gy and 36.0 to 42.0 Gy over the first 2 mm depth in the phantom in selected regions of the PTV, measured with radiochromic film. The prescription dose was 40 Gy. The superficial dose was at the prescription dose or higher in some regions due to the bolus effect of the thermoplastic head mask and the head rest used to aid treatment setup. It is suggested that to achieve the prescription dose at the surface (< or =2 mm depth) bolus or a custom thermoplastic helmet is used.
journal_name
Med Physjournal_title
Medical physicsauthors
Hardcastle N,Soisson E,Metcalfe P,Rosenfeld AB,Tome WAdoi
10.1118/1.2996288subject
Has Abstractpub_date
2008-11-01 00:00:00pages
5061-8issue
11eissn
0094-2405issn
2473-4209journal_volume
35pub_type
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