technetium-tc-99m-tetrofosmin and Soft-Tissue-Neoplasms

P-glycoprotein (Pgp) overexpression has been shown to be correlated with resistance to chemotherapy in patients with malignant bone and soft-tissue tumors. The aim of our study was to investigate the role of 99mTc-tetrofosmin as a functional imaging agent reflecting Pgp expression in these tumors.. Twenty eight patients with various malignant bone and soft-tissue tumors were studied. Radionuclide angiography with 99mTc-tetrofosmin was done first and planar images were acquired at 15 min and 90 min postinjection. Vascular phase was evaluated visually on dynamic images, metabolic state was evaluated both visually and quantitatively on planar images. Quantitative analysis was performed by the calculation of tetrofosmin uptake in the lesion against background and percent washout rate (WR%) of the tracer. Immunohistochemical analysis of Pgp was performed on biopsy specimens and the degree of expression was graded from 0 to 3.. There was a positive correlation between the Pgp score and the washout rate of tetrofosmin (r = 0.73, p = 0.000). The mean washout rate of tetrofosmin from the lesions with Pgp expression (31.81 +/- 6.72) was found to be significantly higher than those of without Pgp expression (21 +/- 3.49) (p = 0.000). No statistically significant correlation was found between 15 min and 90 min uptake ratios (UR) of tetrofosmin and Pgp score (r = -0.10, p = 0.6 and r = -0.21, p = 0.2, respectively). When the cut-off value of 24.5 (according to ROC-analysis) for the washout rate was used to discriminate the lesions with and without Pgp expression, the test yielded a sensitivity value of 87.5% with a specificity of 100%.. In malignant bone and soft-tissue tumors, 99mTc-tetrofosmin uptake were not related to Pgp overexpression. Pgp overexpression was found to be correlated with the washout rate of the tracer. 99mTc-tetrofosmin scintigraphy with washout analysis may not only be a useful method for evaluating Pgp overexpression but also its function.

Topics: Adolescent; Adult; Aged; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biomarkers, Tumor; Bone Neoplasms; Child; Child, Preschool; Female; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Soft Tissue Neoplasms; Statistics as Topic

The aims of this study were to assess the role of (99m)Tc-tetrofosmin scintigraphy in the diagnosis of malignant vs. benign musculoskeletal tumours and to determine the relationship between P-glycoprotein expression and tetrofosmin uptake in malignant lesions. Forty-six patients (32 malignant, 14 benign) with various musculoskeletal lesions were studied. Each patient underwent (99m)Tc-methylene diphosphonate three-phase bone scanning initially. At least 2 days later, dynamic and static (99m)Tc-tetrofosmin scans were obtained. The tetrofosmin scans were evaluated by visual and quantitative analysis. The count ratio of the lesion to the contralateral normal area (uptake ratio, UR) was calculated from the region of interest drawn on the tetrofosmin scan. The lesions were then resected by open biopsy to obtain a histopathological diagnosis. P-glycoprotein levels were determined immunohistochemically in 22 of 32 malignant lesions. A significant difference between the mean UR values of benign and malignant lesions was found (1.36 +/- 0.47 vs. 3.35 +/- 2.08, P = 0.000). Visual analysis showed an accuracy of 85%, and the accuracy of the quantitative analysis was 87% with the threshold level of UR as 1.76. When perfusion findings were added to the evaluation criteria, the accuracies of visual and quantitative analysis were increased to 87% and 89%, respectively. The relationship between the levels of P-glycoprotein and the UR values of tetrofosmin was not statistically significant (r = -0.235, P = 0.2). In addition, the mean UR value of the patients with P-glycoprotein expression was not statistically different from that of the patients without P-glycoprotein expression (3.01 +/- 1.48 vs. 4.27 +/- 2.90, P = 0.297). In conclusion, visually significant tetrofosmin uptake and increased perfusion in a musculoskeletal lesion strongly suggest that the lesion is malignant (positive predictive value, 96%). P-glycoprotein expression was not found to be a major factor interfering with 30 min tetrofosmin uptake in a malignant musculoskeletal lesion. However, the relatively high false-negative rate among negative results (28%) limits the value of (99m)Tc-tetrofosmin scintigraphy as a single diagnostic tool in differentiating between benign and malignant musculoskeletal tumours.

Topics: Adolescent; Adult; Aged; ATP Binding Cassette Transporter, Subfamily B, Member 1; Bone Neoplasms; Child; Child, Preschool; Female; Humans; Image Processing, Computer-Assisted; Immunohistochemistry; Infant; Male; Middle Aged; Muscle Neoplasms; Organophosphorus Compounds; Organotechnetium Compounds; Predictive Value of Tests; Radionuclide Imaging; Radiopharmaceuticals; Regional Blood Flow; Reproducibility of Results; Soft Tissue Neoplasms

The authors describe a 42-year-old man with insular thyroid carcinoma. In this patient, iodine-131 (I-131) and technetium-99m (Tc-99m) tetrofosmin imaging were performed to investigate residual thyroid tissue and metastatic foci of tumor. Both I-131 and Tc-99m tetrofosmin images showed metastatic foci, but Tc-99m tetrofosmin imaging revealed the lesions better than did the I-131 scan. Tc-99m tetrofosmin imaging does not require withholding of thyroid hormone suppression and can be used for follow-up evaluation of patients with insular thyroid carcinoma.

Topics: Adult; Bone Neoplasms; Carcinoma; Humans; Iodine Radioisotopes; Male; Neoplasm, Residual; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Soft Tissue Neoplasms; Thyroid Neoplasms; Thyroidectomy; Whole-Body Counting

Topics: Aged; Biopsy; Diagnosis, Differential; Fluorodeoxyglucose F18; Humans; Leg; Lipoma; Liposarcoma; Magnetic Resonance Imaging; Male; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Soft Tissue Neoplasms

A 49-year-old man was hospitalized for precordial pain. The result of a resting electrocardiograph was normal. Tc-99m tetrofosmin stress myocardial imaging was performed and uptake in the area of the left scapula was seen. The abnormality was caused by a subcutaneous tumor. Histologic examination revealed a hibernoma.

Topics: Coronary Disease; Heart; Humans; Lipoma; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Shoulder; Soft Tissue Neoplasms

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

Medullary carcinoma of the thyroid (MCT) is malignancy derived from the parafollicular cells (or C-cells) of the thyroid. It is usually sporadic, although it is familial in some cases. Several scintigraphic procedures can provide information regarding the primary and metastatic foci of the tumour. We performed whole-body scanning to establish the pathology of MCT using 201Tl, 99Tcm(V)DMSA and 99Tcm-MIBI in 14 patients, and found average sensitivities of 73%, 82% and 81%, respectively. Moreover, we also scanned three patients with 99Tcm-tetrofosmin and identified two of four pathological foci as well as residual thyroid tissue. The sensitivities of 201Tl, 99Tcm(V)DMSA and 99Tcm-MIBI were 100%, 100% and 85% in identifying lymphadenopathies; 40%, 50% and 71% for soft tissue foci; 100% and 100% for foci in pulmonary parenchyma; and 100%, 66% and 100% for recurrences in thyroid gland. Although 99Tcm(V)DMSA identified all bony metastases in three patients (100%), 99Tcm-MIBI detected only two of three foci (66%) and 201Tl none. 201Tl, 99Tcm-MIBI and 99Tcm-tetrofosmin accumulated in residual thyroid tissue, but 99Tcm(V)DMSA did not, as expected. We conclude that these agents were complementary, since they had different sensitivities in different tissues. The tumour-seeking properties of tetrofosmin are to be evaluated in a larger series.

Topics: Adult; Biomarkers, Tumor; Bone Neoplasms; Calcitonin; Carcinoma, Medullary; Female; Humans; Lung Neoplasms; Lymphatic Metastasis; Male; Middle Aged; Neoplasm Recurrence, Local; Organophosphorus Compounds; Organotechnetium Compounds; Prospective Studies; Radionuclide Imaging; Radiopharmaceuticals; Sensitivity and Specificity; Soft Tissue Neoplasms; Technetium Tc 99m Dimercaptosuccinic Acid; Technetium Tc 99m Sestamibi; Thallium Radioisotopes; Thyroid Neoplasms