Preparation of 99mTc-pentavalent DMSA and its uptake by benign bone diseases

Full text: 99mTc-(V)DMSA is a tumour seeking agent that is known for its capability to detect medullary thyroid carcinoma and to be suitable in the detection of tumoral recurrence and/or its metastasis. However, DMSA V could also accumulate in soft tissue tumours, in lung cancer, metastatic diseases, brain tumours and some benign bone diseases. 99mTc-(V)DMSA can be reliably prepared by addition to the DMSA(III) of concentrated NaHCO3. A simple and efficient chromatography analysis uses an ITLSCSG/ MEC in butanol/acetic acid/water (3:2:3) to calculate the ratio DMSA(V):DMSA(III) and the amount of free pertechnetate. Its mechanism of accumulation has been thought to be related to its avidity to some cancer cells but it is also related to glucose mediated acidosis. The uptake of DMSA by benign bone disease has been studied in 68 patients with a known primary cancer, including patients with thyroid medullary carcinoma. An uptake of the DMSA V by benign bone diseases was noticed in more than 80% of the 68 patients, and that could lead to a misinterpretation of the DMSA V total body scan and make for an increased number of false positives in the detection of metastasis or recurrence. This was also confirmed in patients with thyroid medullary carcinoma. (author)