IMPROVED PROSTATE CANCER STAGING WITH DUAL MODE IMAGING

前列腺癌是美国男性的一个重大健康问题，1999年估计有179,300例新确诊病例和37,000例死亡。适当的治疗选择在很大程度上取决于临床分期，而目前的分期技术是不够的。前列环肽(111In-capromab pendeide，11IIn-ProstaScint)是一种放射性标记的单抗，已被引入用于前列腺癌患者的评估。这项拟议研究的目的是利用一种独特的成像系统，结合X射线计算机断层扫描(CT)和单光子发射断层扫描(SPECT)，开发改进的111In-ProstaScint定位和量化方法，为前列腺癌患者提供更准确的分期。在这一临床背景下，该项目将侧重于三个具体目标：(1)开发迭代重建算法，利用伽马射线发射的双能量性质，提供衰减补偿，并解释核医学准直器有限的空间分辨率；(2)评估CT/SPECT对前列腺癌患者进行111In-ProstaScint成像的临床优势；(3)比较111In-ProstaScint图像与CT/SPECT图像的定量评估对单独SPECT图像的视觉解释的作用。方法利用CT/SPECT改善111In-ProstaScint图像的图像质量和定量精度，方法是：(A)将CT的校正纳入SPECT重建和量化过程；(B)利用联合配准的CT图像中的解剖信息来增强放射性核素图像。这项工作的长期目标是开发一种使用肿瘤特异性放射性药物的CT/SPECT成像来评估前列腺癌原发疾病和转移进展的有效方法。我们的目标是提高前列腺癌临床分期的准确性，以便选择适当的治疗方法。更好地选择将受益于局部放射治疗、系统激素治疗、进一步手术，甚至最初的根治性前列腺切除术的患者，应该可以减少患者不必要的风险，改善治疗结果，并提高前列腺癌诊断和治疗的医疗支出的整体成本效益。

Prostate cancer is a significant health problem among men in the United States with an estimated 179,300 new cases being diagnosed and an estimated 37,000 deaths in 1999. Appropriate selection of therapy depends heavily on clinical staging and current staging techniques are inadequate. 111In-capromab pendetide (11IIn- ProstaScint) is a radiolabeled monoclonal antibody that has been introduced to assess patients with prostate cancer. The purpose of the proposed research is to develop improved localization and quantification methods for 111In-ProstaScint using a unique imaging system that combines x-ray computed tomography (CT) with single photon emission tomography (SPECT) to provide more accurate staging for prostate cancer patients. Within this clinical context, the project will focus on three specific aims: (1) Development of an iterative reconstruction algorithm that incorporates the dual-energy nature of the "'In gamma-ray emission, provides attenuation compensation, and accounts for the limited spatial resolution of the nuclear medicine collimator; (2) Assessment of the clinical advantages of CT/SPECT for 111In- ProstaScint imaging of patients with prostate cancer; (3) Comparison of quantitative assessment of 111In-ProstaScint images with CT/SPECT to visual interpretation of the SPECT images alone. Methods using CT/SPECT to improve the image quality and quantitative accuracy of 111In-ProstaScint images will be developed by (a) incorporating corrections from CT into the SPECT reconstruction and quantitation process and (b) augmenting the radionuclide images with anatomical information from the coregistered CT image. The long-term goal of this work is to develop an effective method of assessing primary disease and metastatic progression of prostate cancer using CT/SPECT imaging of tumor-specific radiopharmaceuticals. Our objective is to improve the accuracy of clinical staging of prostate cancer allowing for the selection of appropriate treatment. Better selection of patients who would benefit from localized radiotherapy, systemic hormonal therapy, further surgery, or even initial radical prostatectomy should reduce unnecessary risk to patients, improve therapeutic results, and promote cost- effectiveness of health care spending for diagnosis and treatment of prostate cancer overall.