Effects on skin dose from unwanted air gaps under bolus in photon beam radiotherapy
Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review
Author(s)
Detail(s)
Original language | English |
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Pages (from-to) | 201-204 |
Journal / Publication | Radiation Measurements |
Volume | 32 |
Issue number | 3 |
Publication status | Published - Jun 2000 |
Link(s)
Abstract
The dose under small air gaps located under bolus material of up to 10 mm have been measured with an Attix parallel plate ionization chamber and radiochromic film. For a 6 MV x-ray beam with 10 mm bolus, an air gap of 2 mm produced no reduction in skin dose when measured with the Attix chamber. An air gap of 4 mm will introduce a reduction of dose to the basal layer of approximately 0-4% depending on field size, angle of incidence and other patient specific parameters and a reduction of up to 10% could be seen at the basal cell layer for a 10 mm air gap. The 10% reduction was for a small x-ray field at 60 degrees angle of incidence and was a reduction in dose from 100% of Dmax down to 90% of Dmax. Results at oblique angles of incidence show that larger reductions in dose are seen with increasing angle of incidence. Radiochromic film results agree with the Attix chamber results measuring 2% +2% decrease for a 4 mm gap and 4% +2% for a 10 mm gap at normal incidence. Clinically, results show that small air gaps can reduce skin dose, however, at least 90% of maximum dose is still delivered for air gaps up to 10 mm.
Citation Format(s)
Effects on skin dose from unwanted air gaps under bolus in photon beam radiotherapy. / Butson, Martin J.; Cheung, Tsang; Yu, Peter et al.
In: Radiation Measurements, Vol. 32, No. 3, 06.2000, p. 201-204.
In: Radiation Measurements, Vol. 32, No. 3, 06.2000, p. 201-204.
Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review