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A tissue-equivalent chamber designed for in-phantom dosimetry is described. The use of non-tissue-equivalent material has been restricted to amounts too small to perturb the radiation field significantly. Various chamber sensitivities were obtained by the use of gas fillings and electrodes of different properties, thus making it possible to distinguish among the absorbed doses from fast neutrons, y-rays, and the 14N(n, p)14C reaction. The absorbed dose delivered to a cylinder of tissue by each component of anincompletely thermalizedneutronbeam was measured. A computer code has been developed to calculate the absorbed dosefromx-rays and the I4N(n, p)14C reaction when a cylinder of tissue is irradiated with a beam of thermal neutrons. Measured results are compared with calculated results, and show good agreement.

A promising material for use in a UV film badge dosemeter is diazo film. The optical density of this substance changes on exposure to ultraviolet radiation. The present paper reports some of the relevant factors in the processing of the film and also on its spectral sensitivity. It is evident from our results that development time and volume and concentration of ammonia solution should be standardised. However, after the film has been developed, it is not affected by subsequent UV exposure or by storage for up to one month. Although maximum sensitivity occurs at 405 nm, there is still an easily measurable response at 254 nm. It is concluded that provided procedures are standardised, Diazochrome KBL film is an inexpensive, convenient material for a UV film badge dosemeter with measurable sensitivity down to 254 nm.

Purpose: Mycosis fungoides is a common form of cutaneous T‐cell lymphoma which generally affects the skin. A typical course of treatment may include fractionated total skin electron beam therapy. Given the difficulties in uniformly irradiating some regions of the body and the need for frequent visits within the context of a fractionated protocol, this study investigated the feasibility of delivering the dose using form‐fitting cloth which contained phosphorous‐32 as a source for beta particle irradiation. Methods: A piece of fabric (0.97 g) consisting of a blend of spandex and flame retardant material impregnated with phosphorus‐31 (2000 ppm) was bombarded with neutrons to produce phosphorus‐32. The cloth was then laid flat and a stack of radiochromic film placed on top. Sheets of film and tissue equivalent plastic were layered to form a stack measuring a total of 1 cm thickness and remained sandwiched for 77.3 hr. Results: The initial activity of the activated cloth was 44 μCi of P‐32. The absorbed dose was uniform within planes parallel to the cloth and exponentially dependent on depth, delivering 560cGy at 0.3mm and falling to 20cGy at 3mm. Conclusion: The total dose prescribed for a typical course of TSET for mycosis fungoides is 36Gy delivered over 9 weeks and is expected to treat to at least 5mm depth. Therefore, the P‐32 impregnated cloth may not be clinically indicated to treat this disease given the unfavorable depth‐dose characteristics. However, a major advantage of using form‐fitting cloth is the uniformity with which the dose could be delivered over the skin in areas which are not flat. Increasing the distance between cloth and skin could improve the depth‐dose characteristics.