Comparison of 99mTechnetium-pertechnetate and 123Iodide SPECT with FDG-PET in patients suspicious for breast cancer

Purpose: Breast carcinomas express the Na+/I- symporter and may-albeit not a routine procedure-be imaged with (123)iodide (I-123) and (99m)technetium-pertechnetate ((TcO4-)-Tc-99m) scintigraphy. The aim of our prospective study was the comparison of (TcO4-)-Tc-99m -and I-123-single-photon emission computed tomography (SPECT) with F-18-2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) inpatients suspicious for breast cancer. Methods: Twenty-nine (29) untreated patients suspected of having breast carcinoma were prospectively examined with thorax SPECT with (TcO4-)-Tc-99m (n = 19) or I-123 (n = 10), respectively, and FDG-PET (n = 29) prior to biopsy. Tumor-to-background ratios (TBRs) were calculated for SPECT findings. Mean and maximum standardized uptake values (SUVs) were calculated for PET findings. Findings were compared in an intra- individual lesion-to-lesion analysis. Results: in 28 of 29 patients, malignancy was verified with histopathology. In imaging the primary tumor, sensitivities of (TCO4-)-T-99m-SPECT, I-123-SPECT, and FDG-PET were 63%, 67%, and 89%, respectively. TBR maximum was 2.6 +/- 1.1 in (TCO4-)-T-99m -SPECT and 2.3 +/- 0.6 in I-123-SPECT. In FDG-PET. mean tumor SUV was 4.1 +/- 4 and maximum tumor SUV was 5.4 +/- 5. L In contrast to FDG-PET (TCO4-)-T-99m -SPECT was inefjective in imaging nodal and distant metastases in the thorax, and I-123-SPECT failed in imaging lymph node infiltrations. Distant metastases were not present in patients of the I-123 group, and the value of I-123- SPECT was not evaluated. Conclusions: In cont rast to FDG-PET, (TCO4-)-T-99m- and I-123-SPECT are ineffective in imaging breast carcinoma in clinical practice.