Case of Adult Metastatic Medulloblastoma Demonstrated on 18F-DOPA PET/CT.

ABSTRACT: 18F-DOPA is a promising radiotracer used for both staging and restaging of primary brain tumors based on increased transport via the L-type large neutral amino acid transport system in tumor cells. Adult medulloblastoma is extremely rare. We present a case of 25-year-old man with posterior fossa medulloblastoma treated with surgery followed by chemotherapy and radiotherapy 5 years back, which later developed metastasis to left cerebral lobe treated with gamma knife followed by surgical debulking. Recent 18F-DOPA PET/CT demonstrates recurrence and disease progression on follow-up scan. 18F-DOPA PET/CT is extremely useful for characterizing brain tumors, response assessment, and prognosis.

Therapy-induced bone changes in oncology imaging with 18F-sodium fluoride (NaF) PET-CT.

18F-Sodium fluoride (18F-NaF) is a PET tracer that is mostly used in the evaluation of bone metastasis in oncology cases. Recently, 18F-NaF PET/CT is gaining wide popularity owing to its higher sensitivity over the other conventional bone tracer with higher and rapid single-pass extraction, negligible plasma protein binding, rapid blood, and renal clearance. In the era of constant evolution of cancer therapy regimens, considerable bone health impact is seen in the form of avascular necrosis, insufficiency fractures, among others. A significant number of these therapy-induced changes show high bone turnover and thereby 18F-NaF accumulation, mimicking metastatic lesions. This article summarizes and illustrates the pattern and morphological features of 18F-NaF PET/CT findings in these changes in the context of clinical and therapeutic history.

Incremental Value of 18F-PSMA-1007 PET/CT in Detection of Metastatic Renal Cell Carcinoma to the Brain.

ABSTRACT: 18F-PSMA PET/CT is an emerging standard of care in staging prostate cancer, evaluating biochemical recurrence and response to therapy. Despite the nomenclature, PSMA expression is also documented at the tumor-associated neovasculature of other malignant solid tumors including renal cell carcinoma. We report a case of 44-year-old man known to have renal cell carcinoma who underwent 18F-PSMA and 18F-FDG PET/CT for restaging after radical nephrectomy. A well-defined solitary cerebellar lesion with marked PSMA expression and equivocal FDG uptake was noted. MRI brain confirmed a matching cerebellar metastatic lesion. 18F-PSMA expression in the metastatic RCC raises a prospective guide to futuristic theragnostic uses.

68Ga-PMSA Uptake in the Lung: Metastatic Versus Primary Lung Tumor.

Ga-PSMA is a promising tracer for both primary staging and detection of biochemical recurrence in prostate cancer. PSMA is also expressed in the neovascular endothelium of various solid malignancies possibly due to tumor-associated angiogenic factors and endothelial cell sprouting. We report a case of a 73-year-old man of prostate cancer with rising prostate-specific antigen levels. Ga-PSMA PET/CT was performed, which showed a focal lung lesion, with subsequent histological confirmation of adenocarcinoma of the lung. Incidental lung lesions on Ga-PSMA in prostate cancer patients should elicit a differential of primary lung malignancy, especially if clinical and morphological suspicion is high.