Simultaneous Tc-99m-MDP/I-123-MIBG Imaging of Neuroblastoma Using SPECT-CT

描述（申请人提供）：神经母细胞瘤是儿童期最常见的颅外实体癌，也是婴儿期最常见的癌症。这种疾病经常转移到骨髓（最有可能）、肝脏和其他器官。精确的疾病分期对于确保最合适的治疗计划至关重要。目前用于分期和再分期的一系列影像学检查分别结合了99mtc -二膦酸亚甲基（99mTc-MDP）显像、123i -甲基十二苄基胍（123I-MIBG）显像和计算机断层扫描（CT）成像。平面扫描图像不能在解剖学上与CT共配准，空间分辨率低，不能提供精确的解剖定位，导致病变检测的灵敏度低于断层成像技术。虽然不像显像成像那么频繁，但分别获得的99mTc-MDP和123I-MIBG SPECT也用于神经母细胞瘤患者的成像。滤波后反投影（FBP）是临床应用于SPECT图像重建的标准算法。更先进的迭代重建算法，如西门子的Flash3D，正在临床应用，但仍然非常昂贵。虽然目前的临床方法对神经母细胞瘤成像具有很高的敏感性和特异性，但由于大多数儿童在成像过程中通常需要镇静或全身麻醉，因此减少每次分期和再分期的扫描次数是可取的。更重要的是，在保持相同图像质量的情况下，进一步减少这些年轻患者的剂量是非常可取的。我们建议在SPECT-CT扫描仪上同时使用99mTc-MDP/123I-MIBG SPECT对这些患者进行成像，同时使用非对比增强低剂量CT。我们的方法需要更少的剂量，而不影响图像质量，避免患者重新定位和多次镇静/麻醉。提出了一种低方差联合有序子集期望最大化（LV-JOSEM）重构算法。该算法将通过蒙特卡罗仿真和模型研究进行验证。将双同位素患者研究与序列单同位素研究进行比较，以检测在解剖背景上已知大小、形状和对比度的病变的存在。我们将估计使用LV-JOSEM双放射性核素成像可以减少多少剂量，以达到与使用标准临床方法相同的病变检出率。

DESCRIPTION (provided by applicant): Neuroblastoma is the most common extracranial solid cancer in childhood and the most common cancer in infancy. This disease frequently metastasizes to bone marrow (most likely), liver and other organs. Precise staging of the disease is essential to ensure the most appropriate treatment plan. The current battery of imaging tests for staging and re- staging combines separately acquired 99mTc-methylene diphosphonate (99mTc-MDP) scintigraphy, 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy, and computed tomography (CT) imaging. Planar scintigraphy images, which cannot be anatomically co-registered to CT, have low spatial resolution and do not provide precise anatomic localization, resulting in lower sensitivity for lesion detection as compared to tomographic imaging techniques. Although not as frequent as scintigraphy imaging, separately acquired 99mTc-MDP and 123I-MIBG SPECT are also used to image neuroblastoma patients. Filtered back-projection (FBP) is the standard reconstruction algorithm used in clinic to reconstruct the SPECT images. More advanced iterative reconstruction algorithms, such as Siemens Flash3D, are becoming available in clinic but remain very expensive. Although current clinical approaches offer high sensitivity and specificity for imaging neuroblastoma, it is desirable to reduce the number of scans for each staging and re-staging because most of the children typically require sedation or general anesthesia during imaging. More importantly, it is very desirable to further reduce dose for these young patients while preserving the same image quality. We propose imaging these patients using simultaneous 99mTc-MDP/123I-MIBG SPECT in addition to a non- contrast-enhanced low-dose CT on a SPECT-CT scanner. Our approach will require much less dose without comprising image quality and avoid repositioning of the patient and multiple sedations/anesthesias. A low-variance joint ordered-subset expectation maximization (LV-JOSEM) reconstruction algorithm will be developed. The algorithm will be validated by Monte Carlo simulation and phantom studies. The dual-isotope patient studies will be compared to the sequential single-isotope studies on the basis of performance of lesion detection task in detecting the presence of a lesion of known size, shape, and contrast on an anatomic background. We will estimate how much dose can be reduced using dual-radionuclide imaging with LV-JOSEM to achieve the same lesion detectability as that using the standard clinical approaches. PUBLIC HEALTH RELEVANCE: Neuroblastoma is the most common extracranial solid cancer in childhood and the most common cancer in infancy. The aim of this project is to demonstrate that simultaneous 99mTc-MDP/123I-MIBG SPECT imaging with a low-variance joint ordered-subset expectation maximization (LV-JOSEM) reconstruction algorithm would require much less dose than sequential single-isotope approaches, avoiding repositioning the patient between scans, and eliminating the need for multiple sedations and general anesthesia for imaging of neuroblastoma.