Assessment of Indigenously Developed 99mTc-DTPA Bis-Methionine (99mTc-MDM) Qualitatively and Quantitatively During Initial Clinical Assessment in Breast Cancer Patients

Introduction: Radionuclide-based tracers for SPECT and PET imaging have proven useful in the early detection of breast cancer. While C-11 methionine is an established PET tracer, its high cost and limited availability restrict its widespread clinical use. In contrast, 99mTc-MDM demonstrates promise as an alternative, with uptake facilitated by the overexpression of amino acid transporters, particularly via the LAT1 transporter in tumour cells. It is cost-effective and readily available, making it a potential candidate for identifying malignant breast lesions. Prior to administration, ensuring radiopharmaceutical quality through rigorous quality control is essential to uphold imaging standards in nuclear medicine. Aim: To evaluate both qualitatively and quantitatively the indigenously developed 99mTc-MDM (DTPA-bis-methionine) during its early clinical application in patients presenting with breast lesions. Objectives: To assess the physiological uptake pattern of 99mTc-MDM in patients with breast cancer; To determine the radiolabelling efficiency of the indigenously formulated 99mTc-MDM kits. Results: Physiological uptake of 99mTc-MDM was observed in the kidneys (51/51 patients), liver (50/51), gallbladder (12/51), and bowel (21/51). Quantitative analysis indicated a radiochemical purity of approximately 95%. Conclusion: The indigenously produced 99mTc-MDM kits demonstrated high labelling efficiency (>95%) and consistent physiological biodistribution, primarily involving the kidneys, liver, gallbladder, and bowel. Normal breast tissue in pre-menopausal women exhibited moderate and homogenous tracer uptake, whereas post-menopausal women showed mild and homogenous uptake. These findings suggest that 99mTc-MDM may serve as a viable, cost-effective imaging agent for the evaluation of breast lesions.