A novel model of the skin dose in whole-body UV phototherapy treatment cabins is presented. The model is based on an analysis of the thermal radiation exchange between two surfaces, in this case the UV source and the patient. It is shown to allow analytical treatment of the multiple internal reflections in a treatment cabin that account for around 40% of the skin irradiance. The model provides predictions of the absolute irradiance at the skin and shielding factors in seven different UVA and NB-UVB cabins that are within 6% of those measured using a calibrated radiometer and within 12% for all nine cabins. The model predicts reducing skin irradiances with increasingly patient size, a trend demonstrated in clinical measurements. The exact sensitivity to patient size in automated cabin dosimetry systems, however, varies with in-built sensor positioning. The potential to extend the use of the model to investigate improved design of automated dosimetry systems is discussed.

中文翻译：

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全身UV光疗的热辐射交换模型

提出了一种新的全身紫外线光疗治疗舱皮肤剂量模型。该模型基于对两个表面（在本例中为紫外线源和患者）之间的热辐射交换的分析。它被证明可以对治疗舱中的多次内部反射进行分析处理，这些反射约占皮肤辐照度的 40%。该模型预测了七种不同的 UVA 和 NB-UVB 舱室的皮肤绝对辐照度和屏蔽系数，与使用校准辐射计测量的值相差 6%，所有九个舱室的测量值都在 12% 以内。该模型预测随着患者体型的增加，皮肤辐照度会降低，这是临床测量中证明的趋势。然而，自动机舱剂量测定系统对患者体型的精确敏感性，随内置传感器定位而变化。讨论了扩展模型使用以研究改进的自动剂量测定系统设计的潜力。