Biomedical Photonics Laboratory, Department of Laser Physics and Technology, Higher Institute for Laser Research and Applications, Damascus University, Syria.
Biomedical Engineering Department. Faculty of Mechanical and Electrical Engineering, Damascus University, Syria.
Biomed Res Int. 2020 Mar 23;2020:2061509. doi: 10.1155/2020/2061509. eCollection 2020.
It is well known that interstitial photodynamic therapy (iPDT) of large tumors requires effective planning to ensure efficient delivery of therapeutic dose to the target tumors. This should be achieved in parallel with minimal damage to the nearby intact tissues. To that end, clinical iPDT can be attained using cylindrical diffusing optical fibers (CDFs) as light sources. In this work, we optimize output CDF powers in order to deliver a prescribed light dose to a spherical volume such as a tumor node.
Four CDFs are placed vertically inside the tumor node. The fluence rate is calculated using the diffusion equation. Therapeutic target dose is (20-50) J·cm. The optical properties ( = 0.085 cm, ' = 16 cm) of a breast tumor and the treatment time of 150 sec are used to calculate the fluence rate.
For four CDFs, the therapeutic target dose (20-50) J·cm is delivered to more than 90%. This is the ratio of the total points that receive the target dose in proportion to the total points in the volume of the node of 3 cm in diameter, whereas, in larger nodes, the ratio is decreased to approximately 67%. Five CDFs are required to improve this ratio by more than 10%.
Optimizing delivered powers enables the distribution of the therapeutic dose uniformly in the medium. In addition, this simulation study represents an essential part of a development dosimetry system for measuring and controlling the optical dose in the breast tumors.
众所周知，大面积肿瘤的间质光动力疗法（iPDT）需要有效的规划，以确保将治疗剂量有效地递送到靶肿瘤。这应该在对附近完整组织造成最小损伤的情况下实现。为此，可以使用圆柱形漫射光纤（CDF）作为光源来实现临床 iPDT。在这项工作中，我们优化了输出 CDF 功率，以便将规定的光剂量递送到球形体积，如肿瘤节点。
四个 CDF 垂直放置在肿瘤节点内。使用扩散方程计算辐照度。治疗靶剂量为（20-50）J·cm。使用乳腺癌的光学特性（ = 0.085cm， '= 16cm）和 150 秒的治疗时间来计算辐照度。
对于四个 CDF，超过 90%的节点达到治疗靶剂量（20-50）J·cm。这是接收靶剂量的总点数与直径为 3cm 的节点体积的总点数之比，而在较大的节点中，该比例降低到约 67%。需要五个 CDF 才能将该比例提高 10%以上。
优化输送功率可使治疗剂量在介质中均匀分布。此外，这项模拟研究代表了用于测量和控制乳腺癌中光学剂量的开发剂量测定系统的重要组成部分。
