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

描述（由申请人提供）：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。疾病的精确分期对于确保最适当的治疗计划至关重要。目前用于分期和再分期的一系列成像测试结合了分别采集的99 mTc-亚甲基二膦酸盐（99 mTc-MDP）放射成像、123 I-间碘苄胍（123 I-MIBG）放射成像和计算机断层扫描（CT）成像。平面断层摄影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，导致与断层摄影成像技术相比，病变检测的灵敏度较低。虽然不像放射成像那样频繁，但单独采集的99 mTc-MDP和123 I-MIBG SPECT也用于对神经母细胞瘤患者进行成像。滤波反投影（FBP）是临床上用于重建SPECT图像的标准重建算法。更先进的迭代重建算法，如Siemens Flash 3D，正在临床上使用，但仍然非常昂贵。虽然目前的临床方法提供了高灵敏度和特异性的成像神经母细胞瘤，它是可取的，以减少扫描的数量为每个分期和重新分期，因为大多数儿童通常需要镇静或全身麻醉成像。更重要的是，在保持相同图像质量的同时，进一步降低这些年轻患者的剂量是非常可取的。我们建议使用同步99 mTc-MDP/123 I-MIBG SPECT以及SPECT-CT扫描仪上的非对比增强低剂量CT对这些患者进行成像。我们的方法将需要更少的剂量，而不影响图像质量，并避免患者的重新定位和多次镇静/麻醉。将开发低方差联合有序子集期望最大化（LV-JOSEM）重建算法。该算法将通过蒙特卡罗模拟和体模研究进行验证。将基于病变检测任务的性能，将双同位素患者研究与序贯单同位素研究进行比较，以检测解剖背景上是否存在已知尺寸、形状和对比度的病变。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，以实现与使用标准临床方法相同的病变可检测性。 公共卫生相关性：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。本项目的目的是证明，采用低方差联合有序子集期望最大化（LV-JOSEM）重建算法的99 mTc-MDP/123 I-MIBG SPECT同步成像所需的剂量比顺序单同位素方法少得多，避免在扫描之间重新定位患者，并消除神经母细胞瘤成像所需的多次镇静和全身麻醉。

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.