technetium-tc-99m-tetrofosmin and Sarcoma

99Tcm-methoxyisobutylisonitrile (99Tcm-MIBI) and 99Tcm-tetrofosmin are cationic tracers recognized by the efflux pump P-glycoprotein (Pgp). Verapamil has been shown to be a competitive inhibitor of Pgp, and was one of the first multidrug-resistant reversing agents identified. The aim of this preclinical in vitro study was to evaluate the effects of verapamil on the accumulation of 99Tcm-MIBI and 99Tcm-tetrofosmin in the human breast cancer cell lines MCF-7 and SK-BR-3 and in the human soft tissue sarcoma cell lines SW 982 and SW 1353, in comparison with respective control cells, i.e. without preincubation with verapamil. After preincubation with 10 or 100 microM of verapamil for 15 or 30 min, the 99Tcm-MIBI and 99Tcm-tetrofosmin accumulation in cells was assessed at 10, 30 and 60 min after incubation with these tracers. Addition of verapamil caused a decline in the accumulation of the two tracers at all incubation times, as compared with control cells. These effects of verapamil were neither dose- nor preincubation time-dependent in most cells. Our data indicate that verapamil is not a promising agent for increasing the sensitivity of scintigraphy with 99Tcm-MIBI or 99Tcm-tetrofosmin, or for evaluating Pgp tumour status in these types of tumours.

Topics: Adenocarcinoma; Breast Neoplasms; Calcium Channel Blockers; Cell Line; Cell Survival; Female; Humans; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Sarcoma; Soft Tissue Neoplasms; Technetium Tc 99m Sestamibi; Tumor Cells, Cultured; Verapamil

The purpose of this retrospective study was to elucidate the fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) findings in autoimmune-related pancreatitis (AIP), which is a reversible chronic pancreatitis with an autoimmune cause. The study group comprised six patients with clinically diagnosed AIP. After 370 MBq (10 mCi) of FDG had been injected intravenously, the abdomen and/or the whole body was scanned at 1 h post injection in all patients, and scanning was repeated at 2 h in four patients. PET findings were evaluated visually and/or semiquantitatively using the standardized uptake value (SUV). In four of the six patients, PET demonstrated intense uptake in the whole pancreas, which appeared swollen on computed tomography, and the accumulation increased with time in three patients. In one patient, intense focal uptake in the pancreatic head was observed, and the accumulation decreased over time. In the remaining patient, no abnormal accumulation in the pancreas was observed. Follow-up PET scanning after steroid therapy was performed in three patients, and intense FDG uptake was no longer observed. Our preliminary data show that AIP can cause intense FDG uptake in the pancreas. This fact, and the benign status of the condition, should be kept in mind when making a diagnosis with FDG-PET in patients with pancreatic disorders.

Topics: Cell Survival; Chondrosarcoma; Fibrosarcoma; Furans; Humans; Liposarcoma; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Sarcoma; Sarcoma, Synovial; Technetium Tc 99m Sestamibi; Tumor Cells, Cultured

The uptake characteristics of technetium-99m hexakis-2-methoxyisobutylisonitrile (MIBI), 99mTc-tetrofosmin and 99mTc-furifosmin in human soft tissue sarcoma cell lines were investigated and compared. After 10-120 min of incubation at 37 degrees C, 32 degrees C and 22 degrees C with 99mTc-MIBI, 99mTc-tetrofosmin and 99mTc-furifosmin, the kinetics of cellular uptake of these tracers in human soft tissue sarcoma cells SW 684 (fibrosarcoma), SW 872 (liposarcoma), SW 982 (synovial sarcoma) and SW 1353 (chondrosarcoma) was assessed. The uptake of 99mTc-MIBI, 99mTc-tetrofosmin and 99mTc-furifosmin was temperature dependent. The kinetics of uptake of 99mTc-MIBI and of 99mTc-tetrofosmin was similar between fibrosarcoma and liposarcoma cells, as well as between synovial sarcoma and chondrosarcoma cells. 99mTc-furifosmin showed similar uptake kinetics in all cell lines. The uptake of 99mTc-furifosmin was, however, significantly higher in liposarcoma than in the other cells. The data indicate that the cellular uptake of 99mTc-MIBI, 99mTc-tetrofosmin and 99mTc-furifosmin is dependent on cellular metabolic activity.

Topics: Cell Survival; Chondrosarcoma; Fibrosarcoma; Humans; Liposarcoma; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Sarcoma; Sarcoma, Synovial; Technetium Tc 99m Sestamibi; Tumor Cells, Cultured

Technetium-99m-MIBI was initially developed for heart studies but it can also be used to depict tumors, predict multidrug resistance and evaluate chemotherapy. Recently, 99mTc-tetrofosmin, which exhibits similar physical properties, has been launched for heart studies. Tumor uptake and prediction of multidrug resistance have also been reported regarding the latter tracer. A comparison of these two tracers regarding the detectability of musculoskeletal sarcoma has been made.. Twenty patients with musculoskeletal sarcoma of the extremities or pelvis underwent planar examination after the administration of 99mTc-MIBI and 99mTc-tetrofosmin with an interval of 2-7 days. The tumor activity was compared with one ipsilateral and one contralateral background region.. There was a small, but not significant, difference in favor of 99mTc-MIBI with regard to both background regions.. Technetium-99m-MIBI and 99mTc-tetrofosmin can both be used to visualize musculoskeletal sarcomas. The choice may depend on which agent is used routinely for myocardial studies in the laboratory.

Topics: Adolescent; Adult; Aged; Bone Neoplasms; Female; Humans; Male; Middle Aged; Muscle Neoplasms; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Sarcoma; Technetium Tc 99m Sestamibi