Peptide receptor radionuclide therapy (PRRT) has become an established treatment for patients with inoperable and/or metastatic, well-differentiated neuroendocrine tumors with overexpression of somatostatin receptor type 2 (SSTR-2). The post-therapy 177Lu-DOTATATE whole-body scan not only assesses the biodistribution of the lesions seen on pre-therapy68 Ga-SSTR PET/CT scan but also provides a quick assessment of disease status and dosimetry during treatment. Like any other radionuclide scan, the whole-body 177Lu-DOTATATE scan may also show abnormal radiotracer uptake, which may require further imaging to establish its exact etiology. Though radiotracer emboli mimicking focal pulmonary lesions have been described with 18F-FDG and 68 Ga-DOTANOC PET/CT scans, similar artifacts with post-therapy 177Lu-DOTATATE scans have not been described. Herein, we report two cases of hot emboli in the post-therapy 177Lu-DOTATATE scans.

Somatostatin receptor (SSTR)-based imaging and therapy has emerged as well-established modality in neuroendocrine tumors. However, its role in inflammation imaging is still evolving. We present a 48-year-old male with metastatic neuroendocrine tumor who underwent lutetium-177-based somatostatin receptor-based therapy. The post-therapy scan showed a focal tracer uptake in the left calf muscle in addition to the expected tracer uptake at the primary and metastatic sites. Further, cross-sectional imaging and biochemical investigations revealed peripheral vascular disease (PVD). The incidental tracer uptake in the calf on post-therapy scan potentiates the role of somatostatin receptor scintigraphy in identifying macrophagespecific inflammatory reactions.

Chondrosarcoma is a cartilaginous tumor of mesenchymal origin. The histology and grade of the tumor determine the chances of relapse and survival. These tumors usually respond poorly to chemo-radiotherapy in cases of non-resectable and recurrent disease. 18F-FDG PET/CT has been used in evaluation of recurrence. However, these tumors show only mild to moderate FDG avidity due to their lower mitotic activity and large acellular matrix. These tumors are known to have a high degree of angiogenesis, especially in those of higher grade. We present a case of a 53-year-old man with grade II chondrosarcoma of the left femur showing only mild avidity on 18F-FDG PET/CT but showing moderate to intense tracer avidity on 68Ga-DOTA-RGD2PET/CT. This may enable the use of angiogenesis-targeted positron and beta-emitting radiopharmaceuticals as a potentially new theranostic alternative treatment in cases of refractory metastatic chondrosarcoma.

Pulmonary blastoma (PB) is a rare thoracic malignancy and preoperative diagnosis is challenging. A young man presented with dyspnea and chest pain for 3–4 months and chest-computed tomography (CT) revealed large mass in the left lung upper lobe and pleural effusion. Repeated CT-guided fine-needle aspiration cytology from the lesion and pleural fluid aspiration was negative for malignancy. F-18-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) revealed heterogeneous tracer avidity in left lung mass with areas of necrosis. Real-time PET-CT-guided biopsy from metabolically active component of the lesion revealed biphasic PB on histopathology.

¹⁸F-Fluorocholine (FCH) PET/CT is evolving as a functional imaging modality for the preoperative imaging of abnormal parathyroid tissue(s) helping to localize eutopic and ectopic parathyroid tissue and limit the extent of surgery. FCH PET/CT may show incidental uptake in various thyroid lesions necessitating further evaluation, whereas the role of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in the detection of incidental thyroid nodules is well documented. The case of a middle-aged woman with dual pathology of parathyroid adenoma and papillary thyroid cancer detected on FCH and FDG PET/CT is presented.