Introduction The aim of the study was to retrospectively define specific features of the technetium-99m pentavalent dimercaptosuccinic acid ( 99m Tc-(V)DMSA) and technetium99m 2-methoxy isobutyl isonitrile ( 99m Tc-Sestamibi [ 99m Tc-MIBI]) distribution in ductal breast carcinoma in situ and lobular breast carcinoma in situ (DCIS/LCIS), in relation to mammographic, histological and immunohistochemical parameters.

(99m)Tc-(V)DMSA uptake in UDH correlates with Ki-67 expression. This could prove useful in identifying women with benign but high-risk breast pathologies who might benefit from chemoprophylaxis.

The purpose of this study was to evaluate and compare the diagnostic accuracy of pentavalent technetium-99m dimercaptosuccinic acid [99mTc-(V)DMSA] and 99mTc-methoxyisobutylisonitrile (MIBI) in the detection of primary breast cancer and metastatic lymph node involvement, and in the clarification of cases with indeterminate mammograms. Forty-one women (mean age+/-SD 55+/-7 years) referred for a suspicious breast lesion on physical examination and/or an abnormal mammogram underwent MIBI and (V)DMSA scintimammography (SMM) at separate sessions (48-h interval). Lateral prone and anterior supine images were obtained at 10 and 60 min after administration of 740-925 MBq of each tracer, in the arm contralateral to the breast lesion. The ipsilateral axillary region was also included in the field of view. The results of SMM and mammography were compared with histological findings. Breast cancer was histologically confirmed in 26 patients (mean diameter+/-SD 2.87+/-1.5 cm). Benign lesions were found in 15 patients (mean diameter+/-SD 2.04+/-2.7 cm). Mammography was definitely positive in 23/26 patients with breast cancer and indeterminate in 3/26 (sensitivity 88.4%). In benign lesions, mammography was true negative in 5/15 cases and indeterminate in 10/15 (specificity 33.3%). Both MIBI and (V)DMSA SMM detected 23/26 breast cancers (sensitivity 88.4%) and were true negative in 14/15 (specificity 93.3%). T/B ratios for breast cancer in MIBI and (V)DMSA scans were similar, and significantly higher than for benign lesions. MIBI correctly diagnosed 12/13 and (V)DMSA 11/13 cases in which the findings of mammography were indeterminate. In addition, (V)DMSA detected seven of eight cases of in situ ductal carcinoma (DCIS) associated with infiltrating carcinomas, while MIBI detected only two of these eight cases. (V)DSMA was also diffusely concentrated in benign lesions complicated by epithelial hyperplasia. Metastatic lymph node involvement was successfully imaged in 15/19 patients with metastatic disease by both agents (sensitivity 78.9%), while true-negative scans were observed in 19/22 (specificity 86.3%) patients with benign or malignant tumours without lymph node metastases. Linear regression analysis revealed a high coefficient of correlation between the (V)DMSA and the MIBI T/B ratios (r=0.8 P<0.001). We conclude that both (V)DMSA and MIBI show an excellent ability to detect breast cancer and its lymph node metastases. (V)DMSA also has a tendency to be diffusely and more intensely localised than MIBI in pre-invasive lesions, such as DCIS or epitheliosis, which are at risk of developing into malignancies. (V)DMSA could therefore provide a useful tool in the diagnosis of such lesions and possibly modify a predefined surgical plan. Finally, we believe that both tracers could offer an alternative method for elucidating nondiagnostic mammograms.

The biological behavior and prognosis of gliomas depend largely on cellular proliferation, resistance to chemotherapy, and metastatic potential. Proliferative propensity has significant implications on patient management but its assessment requires tissue sampling; the non-invasive estimation of brain tumor proliferation represents therefore a major goal. Pentavalent technetium-99 m dimercapto-succinic acid [99m Tc-(V)DMSA] is a tumor-seeking radiotracer displaying affinity for gliomas; its intracellular accumulation is directly linked to cell proliferation. We performed a tomographic 99m Tc-(V)DMSA brain scan in a 35-year-old male baring a recurrent glioblastoma multiforme, to depict its proliferative disposition. The patient had been diagnosed 14 months earlier and had been submitted to surgery, followed by adjuvant radiotherapy and temozolomide-based chemotherapy. On clinical suspicion of recurrence 5 months later, magnetic resonance imaging (MRI) revealed a lesion at the site of preceded surgery, which was treated by imatinib mesylate. No improvement was ascertained the following months and radiographic assessment verified tumor progression. Scintitomography revealed avid radiotracer uptake in the entirety of the lesion (the distribution of radioactivity closely conforming to the morphological tumor boundaries), an indication that the neoplasm demonstrated no substantial proliferation decline in response to imatinib. The patient deceased a few weeks later. Mounting in vivo and in vitro evidence indicates that 99m Tc-(V)DMSA is a credible non-invasive proliferation depicter, its cellular accumulation linked closely to phosphate uptake and kinase pathway activation. A potential role in patient management, prognosis estimation, and therapy response monitoring could occur for this tracer.

This study was performed to investigate the relationship between histological type and grade, with the uptake and washout of 99mTc-hexakis-2-methoxyisobutylisonitrile (99mTc-sestamibi, 99mTc-MIBI) and 99mTcV-dimercaptosuccinic acid (99mTcV-DMSA) in breast cancer. Forty-five patients with histologically proven breast cancer had previously been referred for 99mTcV-DMSA and/or 99mTc-MIBI scintimammography. Twenty-five of them underwent both 99mTcV-DMSA and 99mTc-MIBI scintigraphy in a double phase study. Lateral prone and anterior supine images were acquired at 15 and 60 min after administration of 740-925 MBq of each radiotracer. Uptake ratios and retention index were calculated and correlated with histology and grade of malignancy. Histology showed eight different histotypes: 77.7% were infiltrating ductal or lobular carcinomas. Mammography was definitely positive in 32/45, indeterminate in 10 and negative in three cases (sensitivity 71%). 99mTcV-DMSA was true positive in 37/40 (sensitivity 92.5%) and 99mTc-MIBI in 28/30 (sensitivity 93.3%) breast cancers. Uptake ratios were significantly higher in ductal than in lobular carcinomas on 99mTcV-DMSA and 99mTc-MIBI scintigrams at early and delayed phases. Grade II carcinomas had significantly lower values of retention index (rapid washout) than grade III carcinomas. This finding was statistically significant only on 99mTc-MIBI scans and was observed in ductal and lobular carcinomas. The retention index did not show any significant difference between ductal and lobular carcinomas. Uptake ratios were also not statistically different between grade II and III cancers. It is concluded that 99mTc-MIBI and 99mTcV-DMSA uptake in breast cancer is probably related to histological type and may distinguish ductal from lobular carcinomas. To a certain degree, the washout rate may reflect the histological grade, but since grade is not the only factor influencing this phenomenon it should be explored further in conjunction with other parameters by multivariate analysis in order to clarify eventual indirect correlations.