Radiochromic film dosimetry in water phantoms

Radiochromic film is investigated for use in dosimetry in water phantoms as opposed to solid phantoms. Investigations are performed to measure the pen etration rates of water into radiochromic film and to assess the effects on optical density that this penetration causes. The effects of him orientati on during irradiation in water are also tested. Results show that only a sm all penetration rate is seen from water into the film which only affects th e outer areas of the film, with penetration being less than 0.5 mm per hour . The optical density measurements of the film at 660 nm remain unchanged i n the unaffected regions of the radiochromic film. Minimal effects are seen due to beam orientation in a water phantom as opposed to solid water phant oms in which an overestimation in dose is normally seen for parallel irradi ation. Radiochromic film seems to be an adequate detector for dosimetry in a water phantom where high spatial resolution is needed and angle of beam i ncidence at the point of interest is important.