Image-guided treatment planning for pleural Photodynamic Therapy

摘要本资助的总体目标是开发一种集成系统，用于腔内光动力治疗期间的实时PDT剂量测定和光源监测。我们建议开发一种基于红外摄像机的系统，用于实时跟踪用于治疗的光源的运动。同样的跟踪系统将被用于对正在处理的腔体的表面轮廓进行数字化，以进行光通量计算。利用光纤光谱探针，配合红外相机跟踪装置，确定PDT前后胸膜腔表面多点的吸收光谱。吸收光谱的分析将确定这些点的组织氧合和敏化剂浓度。同一探针将能够进行荧光光谱来验证PDT前后的体内药物浓度。吸收光谱还将用于确定体内组织的光学特性，并将这些点作为计算光通量的输入。为了提高非均匀组织光学性质的空间分辨率，我们计划开发一种光谱反射成像系统来确定PDT前后组织光学性质的表面分布。将在体内7个选定的点测量光通量率、吸收光谱和荧光发射的时间变化，并使用考虑腔体几何形状和光学特性的光通量计算算法与计算结果进行比较。PDT剂量将作为药物浓度和光通量的乘积来计算。我们假设使用PDT剂量作为PDT剂量学量来优化光源运动，可以改善PDT治疗的空间均匀性，从而提高其疗效。将在临床前模型中研究一种新的剂量学量，即考虑光通量效应的反应单线态氧浓度，以进一步改善PDT剂量。

DESCRIPTION (provided by applicant): Image-guided treatment planning for pleural Photodynamic Therapy Abstract The overall objective of this grant is to develop an integrated system for real-time PDT dosimetry and light source monitoring during intracavitary photodynamic therapy. We propose to develop an infra- red camera-based system for real-time tracking of the motion of the light source used for treatment. The same tracking system will be used to digitize the surface contour of the cavity being treated for light fluence rate calculation. An optical fiber-based spectroscopic probe, coupled with the IR camera tracking device, will be used to determine absorption spectra at multiple points on the pleural cavity surface before and after PDT. Analysis of the absorption spectrum will determine the tissue oxygenation and the sensitizer concentration at these points. The same probe will be capable of performing fluorescence spectroscopy to verify drug concentration in-vivo before and after PDT. The absorption spectrum will also be used to determine the tissue optical properties in-vivo and use these points as input for light fluence rate calculation. To improve the spatial resolution of the heterogeneous tissue optical properties, we plan to develop a spectral reflectance imaging system to determine the surface distribution of optical properties in tissue before and after PDT. The temporal variations of light fluence rate, absorption spectrum, and fluorescence emission will be measured in- vivo at 7 selected points and compared with calculations using a light fluence calculation algorithm which takes into account the geometry and optical properties of the cavity. PDT dose will be calculated as a product of drug concentration and light fluence rate. We hypothesize that using PDT dose as a PDT dosimetry quantity to optimize light source movement will result in improvement of the spatial uniformity of PDT treatment and thus its efficacy. Further improvement of the PDT dose by a new dosimetric quantity, reacted singlet oxygen concentration that takes into account of light fluence rate effect, will be examined in a preclinical model.