Zhu Timothy C, Liang Xing, Chang Chang, Sandell Julia, Finlay Jarod C, Dimofte Andreea, Rodrigeus Carmen, Cengel Keith, Friedberg Joseph, Glatstein Eli, Hahn Stephen M
Department of Radiation Oncology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104.
Division of Thoracic Surgery, Penn Presbyterian Medical Center, Wright-Saunders, Suite 266, 51 N 39 Street, PA 19104.
Proc SPIE Int Soc Opt Eng. 2011 Feb 28;7886. doi: 10.1117/12.875635.
Uniform light fluence distribution for patients undergoing photodynamic therapy (PDT) is critical to ensure predictable PDT outcome. However, common practice uses a point source to deliver light to the pleural cavity with the light uniformity monitored by 7 detectors placed within the pleural cavity. To improve the uniformity of light fluence rate distribution, we have used a real-time infrared (IR) tracking camera to track the movement of the light point source. The same tracking device is used to determine the surface contour of the treatment area. This study examines the light fluence (rate) delivered between the measurement and calculation in phantom studies. Isotropic detectors were used for in-vivo light dosimetry. Light fluence rate in the pleural cavity is calculated and compared with the in-vivo calculation. Phantom studies show that the surface contour can be determined with an accuracy of 2 mm, with maximum deviation of 5 mm. We can successfully match the calculated light fluence rates with the in-vivo measurements. Preliminary results indicate that the light fluence rate can have up to 50% deviation compared to the prescription in phantom experiments. The IR camera has been used successfully in pleural PDT patient treatment to track the motion of light source in real-time. We concluded that it is feasible to develop an IR camera based system to guide the motion of the light source to improve the uniformity of light distribution.
对于接受光动力疗法（PDT）的患者而言，均匀的光通量分布对于确保可预测的PDT治疗效果至关重要。然而，常规做法是使用点光源向胸腔输送光线，并通过放置在胸腔内的7个探测器监测光的均匀性。为了提高光通量率分布的均匀性，我们使用了实时红外（IR）跟踪摄像头来跟踪光点光源的移动。同一跟踪设备用于确定治疗区域的表面轮廓。本研究在体模研究中考察了测量值与计算值之间的光通量（率）。各向同性探测器用于体内光剂量测定。计算胸腔内的光通量率，并与体内计算结果进行比较。体模研究表明，表面轮廓的确定精度可达2毫米，最大偏差为5毫米。我们能够成功地将计算出的光通量率与体内测量值相匹配。初步结果表明，在体模实验中，光通量率与处方值相比可能存在高达50%的偏差。红外摄像头已成功用于胸腔PDT患者治疗，以实时跟踪光源的运动。我们得出结论，开发一种基于红外摄像头的系统来引导光源运动以提高光分布的均匀性是可行的。
