Tata Memorial Centre Evidence Based Use of Nuclear medicine diagnostic and treatment modalities in cancer.

ABSTRACT: PET/CT and radioisotope therapy are diagnostic and therapeutic arms of Nuclear Medicine, respectively. With the emergence of better technology, PET/CT has become an accessible modality. Diagnostic tracers exploring disease-specific targets has led the clinicians to look beyond FDG PET. Moreover, with the emergence of theranostic pairs of radiopharmaceuticals, radioisotope therapy is gradually making it's way into treatment algorithm of common cancers in India. We therefore would like to discuss in detail the updates in PET/CT imaging and radionuclide therapy and generate a consensus-driven evidence based document which would guide the practitioners of Oncology.

Primary Neuroendocrine Tumor of Prostate in a Case of Metastatic Adenocarcinoma of Lung: Rare Entity with Histopathological and Gallium 68 DOTANOC Positron Emission Tomography Correlation.

Neuroendocrine tumor (NET) of the prostate is an extremely rare entity which represents <1% of the prostatic cancers, but with increasing incidence. Its spectrum encompasses several histological variants ranging from well-differentiated tumor which are often indolent in nature; to aggressive neuroendocrine carcinoma which portends aggressive management. Hence, such rare entities are to be characterized and treated accordingly. We report an unusual case of well-differentiated NET of prostate which was flagged on fluorodeoxyglucose positron emission tomography computed tomography (PET/CT) performed for other indication and confirmed on Gallium-68 DOTANOC PET/CT. Histopathology and immunohistochemistry confirmed the findings subsequently.

Sporadic Cerebellar Hemangioblastoma With Strong SSTR Expression on 68 Ga-DOTANOC PET/CT.

ABSTRACT: Sporadic cerebellar hemangioblastomas are rare with majority of these tumors presenting as a part of von Hippel-Lindau syndrome. We demonstrate an unusual case of a symptomatic sporadic cerebellar hemangioblastoma mimicking a meningioma on MRI and 68 Ga-DOTANOC PET imaging.

Ga-68 Prostate-Specific Membrane Antigen PET/CT: Imaging and Clinical Perspective in Prostate Cancer: Imaging and Clinical Perspective in Prostate Cancer.

Imaging in prostate cancer has become increasingly important over time, as the incidence of prostate cancer has been on the rise and better screening techniques have emerged. The development of personalized systemic therapies highlights the unmet need for whole-body imaging. Prostate-specific membrane antigen (PSMA) PET, with its ease of performance and mechanism of localization to prostatic tumor cells, has now emerged as a preferred modality for diagnosis, staging, and treatment response assessment. In this context, PSMA PET can help in mapping the disease extent, both the skeletal and visceral spread, to plan targeted therapeutic approaches.

Radiation-Induced Meningioma in a Case of Medulloblastoma Treated 11 Years Ago-Detected on 68Ga-DOTANOC PET/CT.

ABSTRACT: Medulloblastomas, especially the sonic hedgehog subgroup, are treated aggressively with surgery and chemoradiotherapy, as they are associated with high local site recurrence rate and poor overall survival. Radiation-induced meningioma is the most common delayed complication of craniospinal irradiation. This needs to be differentiated from meningeal or ependymal metastases as the later need aggressive management. We report one such rare case, in a patient who completed treatment for medulloblastoma 11 years ago, was in remission, and now presented with dural-based lesions.

All that Glitters on PSMA is Not a Lesion: An Unusual Artifact on PSMA PET/CT.

Nonspecific uptake of prostate-specific membrane antigen (PSMA) on PSMA positron-emission tomography/computed tomography (CT) is normally encountered in benign conditions, which is detected on morphological changes on CT component. However, having a site of uptake without any CT finding is a rare occurrence. We herewith report one such rare case of a 66-year-old male with metastatic prostatic adenocarcinoma, who demonstrated an incidental finding of intense focal PSMA uptake in the lung parenchyma.

Brain FET PET tumor-to-white mater ratio to differentiate recurrence from post-treatment changes in high-grade gliomas.

BACKGROUND AND PURPOSE: Highergrade glial neoplasms undergo standard treatment with surgery, radiotherapy, and alkylating agents. There is often a clinical/neuroimaging dilemma in the post-treatment setting to differentiate disease recurrence from treatment-related changes. FET (fluoro-ethyl-tyrosine) PET has emerged as a molecular imaging modality for cases where MR imaging is inconclusive. This study aims to develop a cutoff on FET PET for differentiating true recurrence from post-treatment changes. METHODS: We retrospectively analyzed72 patientswith post-treatment grade 3 or 4 brain gliomas. Five to six mCi of 18 F-FET was injected and static imaging of the brain was performed at 20 min. A tumor-to-white matter (T/Wm) ratio was used as semiquantitative parameter. A T/Wm cutoff of 2.5 was used for image interpretation. Imaging findings were confirmed by either histopathologic diagnosis in a multidisciplinary joint clinic or based on follow-up of clinical and neuroimaging findings. RESULTS: Forty-one of 72 patients (57%) showed recurrent disease on FET PET. Thirty-five of them were confirmed to have tumor recurrence; six patients showed post-treatment changes. Thirty-one of 72 patients (43%) showed post-treatment changes on FET PET; 27 were confirmed as post-treatment change and four patients had tumor recurrence on subsequent MR imaging. An optimum T/Wm cutoff of 2.65 was derived based on receiver operating characteristic analysis with a sensitivity of 80% and specificity of 87.5%. CONCLUSION: Static FET PET can be used as problem-solving imaging modality with a T/Wm cutoff of 2.65 to differentiate late recurrence from post-treatment changes in grade 3 or 4 brain gliomas with equivocal MR features.

Unusual Variant of Breast Cancer Presenting With Pituitary Symptoms Detected on 68Ga-DOTATATE PET/CT.

ABSTRACT: Carcinoma of breast with neuroendocrine differentiation is an extremely rare entity, especially in male population. Although the "garden variety" of male breast cancers is often metastatic at presentation, with an aggressive course, there is hardly any literature about neuroendocrine variants. We report a case of a 57-year-old man who had pituitary symptoms, which on 68Ga-DOTANOC PET/CT imaging turned out to be a metastatic lesion, with somatostatin expressing primary in breast and other sites, with histopathological confirmation of neuroendocrine differentiation in breast cancer.

Rare Presentation of Radiation-induced Sarcoma Detected on F-18 FDG Positron Emission Tomography/Computed Tomography in a Treated Case of Giant Cell Tumor.

Giant cell tumors (GCTs) are benign bone lesions which are treated with curettage and bone grafting. Infrequently, GCTs show local site recurrences which are then treated with either surgical excision or radiation therapy. Radiation-induced sarcoma is rarely seen as a late complication of radiation therapy which needs to be differentiated from recurrent GCT. We report one such rare case of radiation-induced sarcoma detected on Flourine-18 fluorodeoxyglucose (18F FDG) positron emission tomography/computed tomography in a 40-year-old male who was treated with radiation therapy for recurrent GCT 9 years ago.