An Liu, PhD
Radiation Oncology Department
City of Hope Medical Center
Duarte, CA 91010
Radioimmunotherapy (RIT) utilizes monoclonal antibodies (MABs) as a carrier to send radionuclides to tumor sites. The concept and current clinical status of various RIT agents are discussed. In order to calculate the absolute radiation dose received by tumor and other critical organs, an integrated PC-based radionuclide imaging and therapy treatment planning and dosimetry system (RTDS) was developed. The overall design of RTDS is based on an object-oriented model. It includes two major components: a database subsystem and a calculation module subsystem. The database developed under Microsoft Access stores and organizes the clinical data. Calculation modules developed with Microsoft Visual Basic are the calculation processes needed to estimate the final absorbed radiation doses. These consist of 4 subsystems: imaging-processing module, quantitative activity calculation module, modeling module and dose calculation module. The imaging-processing module handles image display and processing. The quantitative activity calculation module estimates the radioactivities in organs. Here, the user is provided with three options of algorithm: the generally used conjugate view method, our CT assisted matrix inversion (CAMI) method and quantitative SPECT. The modeling module handles the modeling of biological data. Both simple curve fitting routines and compartment model are incorporated into the system. The dose calculation module estimates absorbed radiation doses. Two dosimetry models are developed: the generally used MIRDOSE3 algorithm and our Monte Carlo assisted voxel source kernel (MAVSK) algorithm which uses the patient CT volume to perform real-time (calculation under 1 minute) patient-specific dosimetry analysis and generate dose volume histograms (DVH). All final and intermediate dosimetry results are saved to and tracked by the database. RTDS will greatly improve the quality of dosimetry analyses for radionuclide imaging and therapy, especially for radioimmunotherapy. It provides a user-friendly software program and standard format for internal emitter absorbed dose estimation.
TB22 - 放射性核素成像及治疗剂量计算系统
An Liu, PhD
Radiation Oncology Department
City of Hope Medical Center
Duarte, CA 91010
放射免疫治疗（RIT）利用单克隆抗体作为载体将放射性核素运送到肿瘤部位。这里阐述RIT的概念和各种RIT制剂的临床现状。为了计算肿瘤和其它重要器官的剂量，开发了在微机上运行的核素成像、治疗计划与剂量计算系统（RTDS）软件。该软件的设计基于面向对象的方法，包括两部分：数据库子系统和计算模块子系统。数据库使用Microsoft Access开发，用于存储、组织临床数据。计算模块子系统使用Microsoft Visual Basic开发，用于计算评估最终的吸收剂量，包括4个模块：图像处理模块、放射性活度定量计算模块、建立模型模块及剂量计算模块。图像处理模块进行图像的显示和处理；放射性活度定量计算模块计算器官中的放射性活度，系统提供3种算法：常用的目测法、CT辅助逆矩阵法(CAMI)、及定量的SPECT；建立模型模块对生物学数据建立模型，系统提供的模型有简单的曲线拟合模型和房室模型；剂量计算模块计算吸收剂量，有两种算法：常用的MIRDOSE3算法和借助Monte Carlo的体素源核(MAVSK)算法。MAVSK算法根据患者的CT数据实时（计算时间<1分钟）进行患者剂量分析并生成剂量体积直方图（DVH）。所有中间和最终的剂量计算结果都存储到数据库中，并可以检索。RTDS将极大提高放射性核素成像和治疗（尤其是放射免疫治疗）剂量分析的质量，其用户界面友好，为内照射吸收剂量估算提供了一种标准方式。