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 ((123)I) and (99m)technetium-pertechnetate ((99m)TcO(4)(-)) scintigraphy. The aim of our prospective study was the comparison of (99m)TcO(4)(-)--and (123)I-single-photon emission computed tomography (SPECT) with (18)F-2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) in patients suspicious for breast cancer. METHODS: Twenty-nine (29) untreated patients suspected of having breast carcinoma were prospectively examined with thorax SPECT with (99m)TcO(4)(-) (n=19) or (123)I (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 (99m)TcO(4)(-)-SPECT, (123)I-SPECT, and FDG-PET were 63%, 67%, and 89%, respectively. TBR maximum was 2.6+/-1.1 in (99m)TcO(4)()-SPECT and 2.3+/-0.6 in (123)I-SPECT. In FDG-PET, mean tumor SUV was 4.1+/-4 and maximum tumor SUV was 5.4+/-5.1. In contrast to FDG-PET, (99m)TcO(4)()-SPECT was ineffective in imaging nodal and distant metastases in the thorax, and (123)I-SPECT failed in imaging lymph node infiltrations. Distant metastases were not present in patients of the (123)I group, and the value of (123)I-SPECT was not evaluated. CONCLUSIONS: In contrast to FDG-PET, (99m)TcO(4)(-) and (123)I-SPECT are ineffective in imaging breast carcinoma in clinical practice.

Changes in salivary gland function after radiotherapy of head and neck tumors measured by quantitative pertechnetate scintigraphy: comparison of intensity-modulated radiotherapy and conventional radiation therapy with and without Amifostine.

PURPOSE: The aim of this study was to compare changes in salivary gland function after intensity-modulated radiotherapy (IMRT) and conventional radiotherapy (RT), with or without Amifostine, for tumors of the head-and-neck region using quantitative salivary gland scintigraphy (QSGS). METHODS AND MATERIALS: A total of 75 patients received pre- and post-therapeutic QSGS to quantify the salivary gland function. In all, 251 salivary glands were independently evaluated. Changes in the maximum uptake (DeltaU) and relative excretion rate (DeltaF) both pre- and post-RT were determined to characterize radiation-induced changes in the salivary gland function. In addition, dose-response curves were calculated. RESULTS: In all groups, maximum uptake and relative excretion rate were reduced after RT (DeltaU

PET and SPECT for detection of tumor progression in irradiated low-grade astrocytoma: a receiver-operating-characteristic analysis.

UNLABELLED: Differentiation between tumor progression and radiation necrosis is one of the most difficult tasks in oncologic neuroradiology. Functional imaging of tumor metabolism can help with this task, but the choice of tracer is still controversial. This prospective study following up irradiated low-grade astrocytoma (LGA) was, to our knowledge, the first receiver-operating-characteristic (ROC) analysis that intraindividually evaluated the diagnostic performance of the SPECT tracers 3-[(123)I]iodo-alpha-methyl-L-tyrosine (IMT) and (99m)Tc(I)-hexakis(2-methoxyisobutylisonitrile) (MIBI) and the PET tracer (18)F-FDG. METHODS: We examined 17 patients, initially with histologically proven LGA and treated by stereotactic radiotherapy, who presented with new gadolinium-diethylenetriaminepentaacetic acid-enhancing lesions (n = 26) on MRI. At that time, MRI could not differentiate between progressive tumor and nonprogressive tumor. This MRI examination was closely followed by (18)F-FDG PET and by (99m)Tc-MIBI and (123)I-IMT SPECT. Lesions were classified as progressive tumor (n = 17) or nonprogressive tumor (n = 9) on the basis of prospective follow-up (through clinical examination, MRI, and proton MR spectroscopy) for 26.6 +/- 6.6 mo after PET or SPECT. RESULTS: (123)I-IMT yielded the best ROC characteristics and was the most accurate for classification, with an area under the ROC curve (A(z)) of 0.991. The A(z) of (18)F-FDG (0.947) was not significantly lower than that of (123)I-IMT. The difference in the A(z) of (99m)Tc-MIBI (0.713) from the A(z) of the other tracers used in our study was highly significant (P

Evaluation of salivary gland function after treatment of head-and-neck tumors with intensity-modulated radiotherapy by quantitative pertechnetate scintigraphy.

PURPOSE: To evaluate salivary gland function after inversely planned stereotactic intensity-modulated radiotherapy (IMRT) for tumors of the head-and-neck region using quantitative pertechnetate scintigraphy. METHODS AND MATERIALS: Since January 2000, 18 patients undergoing IMRT for cancer of the head and neck underwent pre- and posttherapeutic scintigraphy to examine salivary gland function. The mean dose to the primary planning target volume was 61.5 Gy (range 50.4-73.2), and the median follow-up was 23 months. In all cases, the parotid glands were directly adjacent to the planning target volume. The treatment planning goal was for at least one parotid gland to receive a mean dose of <26 Gy. Two quantitative parameters (change in maximal uptake and change in the relative excretion rate before and after IMRT) characterizing the change in salivary gland function after radiotherapy were determined. These parameters were compared with respect to the dose thresholds of 26 and 30 Gy for the mean dose. In addition, dose-response curves were calculated. RESULTS: Using IMRT, it was possible in 16 patients to reduce the dose for at least one parotid gland to < or =26 Gy. In 7 patients, protection of both parotid glands was possible. No recurrent disease adjacent to the protected parotid glands was observed. Using the Radiation Therapy Oncology Group/European Organization for the Research and Treatment of Cancer scoring system, only 3 patients had Grade 2 xerostomia. No greater toxicity was seen for the salivary glands. The change in the relative excretion rate was significantly greater, if the parotid glands received a mean dose of > or =26 Gy or > or =30 Gy. For the change in maximal uptake, a statistically significant difference was seen only for the parotid glands and a dose threshold of 30 Gy. For the end point of a reduction in the parotid excretion rate of >50% and 75%, the dose-response curves yielded a dose at 50% complication probability of 34.8 +/- 3.6 and 40.8 +/- 5.3 Gy, respectively. CONCLUSION: Using IMRT, it is possible to protect the parotid glands and reduce the incidence and severity of xerostomia in patients. Doses <26-30 Gy significantly preserve salivary gland function. The results support the hypothesis that application of IMRT does not lead to increased local failure rates.