Gallium-68 imaging for Neuroendocrine tumors and Prostate cancer
Neuroendocrine tumors (NETs) are rare group of neoplasm’s arising from nervous and endocrine systems. Somatostatin analogue imaging is a functional imaging modality of choice for evaluating the NETs. Recent availability of positron emitting radioisotope labeled somatostatin analogues to image neuroendocrine cancers has been used in management of patients with NETs. 68Ga-DOTATATE PET/CT has demonstrated superiority in lesion detection compared to Octreo scan, MIBG scintigraphy and MRI.
Neuroendocrine tumors (NETs) are a rare group of neoplasm’s with an incidence of about 35 cases per 100,000 people in the United States. The defined characteristic of NETs is the expression of somatostatin receptors (SST). This unique feature has enabled the field of nuclear medicine and molecular imaging to image these tumors with radio-labeled somatostatin analogues agent. Octreotide, a long-acting somatostatin analogue, was initially used in 1989 and since then it evolved as an important agent in the initial evaluation and management of NETs using molecular imaging techniques. However, gamma imaging using 111In-octreotide has several limiting factors which decreased the image quality and overall efficiency of the test. These include low image quality of indium 111 isotope, increased physiological uptake which restricts detection of small lesions, prolonged imaging protocol and relatively high radiation dose to the patients. . 68Ga-DOTATATE PET/CT has proved superiority in detecting such tumors more accurately; even smaller tumors have been detected.
Prostate cancer (PCa) is the most frequent tumor entity in men worldwide and an increasing incidence has been noted in recent years. An important problem in clinical management is the development of tumor recurrence after prostatectomy, radiotherapy or other local treatment modalities. In most cases, recurrence after initial therapy is diagnosed either by two consecutive prostate-specific antigen (PSA) values of ≥0.2 μg/l after prostatectomy or external beam radiation therapy.
One of the key issues is early detection of recurrent disease. If the tumor is accessible for surgery or external radiation therapy, patients may be cured or systemic therapy and the resultant side effects can be delayed. However, the prerequisite of these approaches is an accurate diagnostic modality with high sensitivity and specificity. To date, this is a major challenge for all conventional imaging methods. 68Ga-labelled PSMA-targeted radio ligand is one of the most recent developments in clinical application showing early and accurate detection of prostate tumors and metastatic spread.
Such facility has been installed in BMCHRC recently and is being used for NET’s and prostate cancer routinely.