SIGNIFICANCE Photodynamic therapy (PDT) could become a treatment option for nonmuscle invasive bladder cancer when the current high morbidity rate associated with red light PDT and variable PDT dose can be overcome through a combination of intravesical instillation of the photosensitizer and the use of green light creating a steep PDT dose gradient. AIM To determine how a high PDT selectivity can be maintained throughout the bladder wall considering other efficacy determining parameters, in particular, the average optical properties of the mucosal layer governing the fluence rate multiplication factor, as well as the bladder shape and the position of the emitter in relationship to the bladder wall. APPROACH We present three irradiance monitoring systems and evaluate their ability to enable selective bladder PDT considering previously determined photodynamic threshold values for the bladder cancer, mucosa and urothelium in a preclinical model, and the photosensitizer's specific uptake ratio. Monte Carlo-based light propagation simulations performed for six human bladders at the time of therapy for a range of tissue optical properties. The performance of one irradiance sensing device in a clinical phase 1B trial is presented to underline the impact of irradiance monitoring, and it is compared to the Monte Carlo-derived dose surface histogram. RESULTS Monte Carlo simulations showed that irradiance monitoring systems need to comprise at least three sensors. Light scattering inside the bladder void needs to be minimized to prevent increased heterogeneity of the irradiance. The dose surface histograms vary significantly depending on the bladder shape and bladder volume but are less dependent on tissue optical properties. CONCLUSIONS We demonstrate the need for adequate irradiance monitoring independent of a photosensitizer's specific uptake ratio.

中文翻译：

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非肌肉浸润性膀胱癌所需的最小 PDT 光剂量测定。

意义 光动力疗法 (PDT) 可以成为非肌肉浸润性膀胱癌的治疗选择，因为目前与红光 PDT 和可变 PDT 剂量相关的高发病率可以通过膀胱内滴注光敏剂和使用绿光产生的组合来克服。陡峭的 PDT 剂量梯度。目的 确定如何在考虑其他功效确定参数的情况下在整个膀胱壁保持高 PDT 选择性，特别是控制注量倍增因子的粘膜层的平均光学特性，以及膀胱形状和位置发射器与膀胱壁的关系。方法我们介绍了三种辐照度监测系统，并考虑到先前在临床前模型中确定的膀胱癌、粘膜和尿路上皮的光动力阈值以及光敏剂的特定吸收率，评估它们启用选择性膀胱 PDT 的能力。在治疗时对六个人类膀胱进行了基于蒙特卡罗的光传播模拟，以获得一系列组织光学特性。展示了一种辐照度传感设备在临床 1B 期试验中的性能，以强调辐照度监测的影响，并将其与蒙特卡罗衍生的剂量表面直方图进行比较。结果 蒙特卡罗模拟表明，辐照度监测系统需要至少包含三个传感器。需要尽量减少膀胱空隙内的光散射，以防止辐照度的不均匀性增加。剂量表面直方图根据膀胱形状和膀胱体积而显着变化，但对组织光学特性的依赖性较小。结论 我们证明了独立于光敏剂特定吸收率的足够辐照度监测的必要性。