Measurement of off-axis and peripheral skin dose using radiochromic film.
A radiotheraphy skin dose profile can be obtained with radiochromic film. The central axis skin dose relative to Dmax for a 10 x 10 cm2 field size was found to be 22%, 17% and 15.5% for 6 MV, 10 MV and 18 MV photon beams. Peripheral dose increased with increasing field size. At 10 MV the skin dose 2 cm outside the geometric field edge was measured as 6%, 10% and 17% for 10 x 10 cm2, 20 x 20 cm2 and 30 x 30 cm2 field sizes respectively. Off-axis skin dose decreased as distance increased from central axis for fields with Perspex block trays. For a 20 x 20 cm2 field, an approximately 5-8% drop in percentage skin dose was observed from central axis to the beam edge.
City University of Hong Kong, Department of Physics and Materials Science, Kowloon Tong.
M J
MJ
Butson
P K
PK
Yu
P E
PE
Metcalfe
D055592:Biophysical Phenomena; D001703:Biophysics; D005373:Film Dosimetry; D006801:Humans; D019047:Phantoms, Imaging; D017785:Photons / Q000009:adverse effects; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy / Q000009:adverse effects*; D012542:Scattering, Radiation; D012867:Skin / Q000528:radiation effects*; D014962:X-Ray Film