This trial was conducted to determine the pharmacokinetics, dosimetry, dose-limiting toxicity, and the maximum tolerated dose of iodine-131 humanized MN-14 immunoglobulin G (131I-hMN-14 IgG), a humanized complementary-determining region-grafted anti-carcinoembryonic antigen monoclonal antibody, in metastatic gastrointestinal and colorectal cancer patients. Patients were divided into 2 groups: group A consisted of patients who had prior external beam radiation therapy (n = 8), and group B included patients who had received standard chemotherapy (n = 13). All patients received a diagnostic infusion of 131I-hMN-14 IgG (approximately 8.0 mCi, 15 mg/m2) to study the pharmacokinetics, biodistribution, and dosimetry. One week later, 17 of 21 patients received infusional therapy of escalating radioactive doses of 131I-hMN-14 IgG. Blood pharmacokinetics and quantitative imaging were performed again after the therapeutic dose. Radiation-absorbed doses to normal organs and tumors were determined by MIRDOSE-3 algorithms. The primary dose-limiting toxicity was hematologic toxicity at 40 mCi/m2. The blood half-life (n = 20) was identical for the diagnostic and therapy infusions. The mean red marrow dose was 2.2 +/- 2.4 cGy/mCi. The mean tumor radiation dose (n = 8) was 24.2 +/- 22.6 cGy/mCi. Tumor targeting was seen in most large metastatic lesions. No objective responses were seen in these heavily pretreated and mostly advanced patients. In conclusion, 131I-hMN-14 IgG has good targeting, good tumor to normal organs radiation absorbed ratios, and an acceptable toxicity profile in advanced metastatic gastrointestinal and colorectal cancer patients.

Adenocarcinoma↗

PubMed2002

Comparison of 123I scintigraphy at 5 and 24 hours in patients with differentiated thyroid cancer.

UNLABELLED: This study was performed to determine differences in 123I image quality at 5 and 24 h for the detection of residual thyroid or recurrent disease in patients with differentiated thyroid cancer and to evaluate which of these approaches provides the optimal yield compared with scans obtained after 131I therapy. METHODS: The study included 99 patients (70 women, 29 men). Histopathology included 88 papillary cancers, 7 follicular cancers, and 4 Hürthle cell tumors. Each patient previously had a near-total thyroidectomy. Seventy patients were receiving initial 131I therapy, and 29 had undergone prior radioablative therapy with 131I. Whole-body images and spot views of the neck and chest were obtained with a dual-head scanner at 5 and 24 h after the oral administration of 56 MBq (1.5 mCi) Na123I. In addition, tomographic images of the neck and chest were obtained in 26 patients. The images obtained at 5 and 24 h were evaluated for the number of lesions visualized and the image quality. Seventy-four patients received radioablative therapy after this diagnostic work-up. Whole-body images were obtained on these patients 7 d after 131I therapy and were compared with the diagnostic scans. RESULTS: Overall, images acquired 5 and 24 h after oral administration of 56 MBq (1.5 mCi) 123I were concordant in 73% of patients. For 25 patients (25%), 24-h scanning was superior by detecting additional neck foci or confirming equivocal neck foci (20 patients) and confirming equivocal pulmonary uptake (5 patients). In the subset of patients undergoing surveillance imaging after prior 131I ablation therapy with positive scans, 24-h images were superior in 66%. In 3 patients, SPECT revealed additional foci compared with planar images at 5 h. These foci were also clearly identified on the planar images obtained at 24 h. Images obtained after therapy did not identify additional sites of tumor involvement compared with those noted on 24-h images but did reveal more foci of residual thyroid tissue in 5 patients. CONCLUSION: The diagnostic yield of planar diagnostic 123I scintigraphy at 24 h was superior to that at 5 h for lesion detection and image quality, and images obtained after 131I therapy did not reveal unknown metastatic foci.

Adenocarcinoma, Follicular↗

PubMed2002

Dual time point 18F-FDG PET for the evaluation of pulmonary nodules.

UNLABELLED: 18F-FDG PET has reached widespread application in the assessment of pulmonary nodules. This study compares the diagnostic accuracy of standard 18F-FDG PET scanning with those of dual time point 18F-FDG PET scanning. METHODS: Thirty-six patients (21 women, 15 men; mean age, 67 y; range, 36-88 y) with 38 known or suspected malignant pulmonary nodules underwent PET of the thorax at 2 time points: scan 1 at 70 min (range, 56-110 min) and scan 2 at 123 min (range, 100-163 min) after the intravenous injection of 2.5 MBq 18F-FDG per kilogram of body weight. All scanning was performed on a dedicated C-PET scanner. The mean interval between the scans was 56 min (range, 49-64 min). Regions of interest were overlaid onto each fully corrected image in the areas of the radiographically known lung densities. The standardized uptake values (SUVs) were calculated for both time points. RESULTS: Surgical pathology and follow-up revealed 19 patients with 20 malignant tumors, whereas 16 patients had benign lesions. The tumor SUVs (mean +/- SD) were 3.66 +/- 1.95 (scan 1) and 4.43 +/- 2.43 (scan 2) (20.5% +/- 8.1% increase; P < 0.01). Four of 20 malignant tumors had SUVs of <2.5 on scan 1 (range, 1.12-1.69). Benign lesions had SUVs of 1.14 +/- 0.64 (scan 1) and 1.11 +/- 0.70 (scan 2) (P = not significant). Standard PET scanning (single time point) with a threshold SUV of 2.5 (at time point 1) reached a sensitivity of 80% and a specificity of 94%; dual time point scanning with a threshold value of 10% increase between scan 1 and scan 2 reached a sensitivity of 100% with a specificity of 89%. CONCLUSION: Dual time point 18F-FDG PET results in a very high sensitivity and specificity for detection of malignant lung tumors.

Adenocarcinoma↗

PubMedDate not supplied

2-Deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography in characterization of solid renal masses.

UNLABELLED: The present study was aimed to evaluate the ability of 2-deoxy-2-[F-18]fluoro-D -glucose (FDG)-positron emission tomography (PET) in characterization of solid renal masses visualized by computed tomography (CT)/magnetic resonance imaging (MRI) in patients with suspected or known malignancies. METHODS: Twenty-eight solid renal masses (20 unilateral and four bilateral, Size ranges, 1.0-8.4 cm) were evaluated in 24 patients. The results were correlated with histopathology in 15 patients, and clinical follow-up and conventional imaging in all patients. RESULTS: Of the 28 solid renal masses, 10 were primary (nine malignant, one benign) and 18 were metastatic renal tumors. FDG-PET accurately depicted 23 of 27 (85%) malignant renal masses. Of the 10 primary renal tumors, FDG-PET was true positive in eight of nine (89%), true negative in one and false negative in one. The maximum and average standardized uptake values (SUVs) for FDG positive primary renal malignant tumors were 7.9 +/- 4.9 and 6.0 +/- 3.6, respectively. In addition to the characterization of primary tumors, FDG-PET was valuable in primary staging and altered treatment in 30% of patients (three of 10). Of the 18 metastatic renal masses, FDG-PET was positive in 15 (83%) masses. The maximum and average SUVs of metastatic renal masses were 6.1+/- 3.4 and 4.7+/- 2.8, respectively. There was no significant difference in maximum and average SUVs between primary and metastatic renal masses (p=0.3 and p=0.3). CONCLUSION: Despite the physiological excretion of FDG by the kidneys, FDG-PET can be employed effectively in characterization of solid renal masses in patients with suspected or known malignancies. We propose that FDG-PET could be useful as a complimentary modality to conventional imaging in these patients.

Adult↗

PubMedDate not supplied

Standardized uptake values of normal breast tissue with 2-deoxy-2-[F-18]fluoro-D: -glucose positron emission tomography: variations with age, breast density, and menopausal status.

OBJECTIVE: This study was conducted to assess the effect of breast density, age, and menopausal status on the 2-deoxy-2-[F-18]fluoro-D: -glucose (FDG) uptake in normal breast tissue by quantitative standardized uptake values (SUV). METHODS: A total of 96 patients (premenopausal 54; postmenopausal 42) with histologically proven unilateral breast cancer who underwent FDG-positron emission tomography (PET) scans for staging were included in this study. The median age was 52+/-11 years (range 32-79 years). Fifty-nine patients had grade III or IV mammographic density (dense breast), whereas 37 patients had grade I or II breast density (nondense) according to the ACR Lexicon criteria. In the present study, we analyzed maximum and average SUVs for contralateral normal breast. RESULTS: Maximum and average SUVs for normal dense breasts were 1.02+/-0.30 and 0.84+/-0.27, respectively. Similar values for the nondense breasts were 0.66+/-0.24 and 0.53+/-0.23, respectively. Both maximum and average SUVs of dense breasts were significantly higher than those of nondense breasts (p<0.001). There was no significant difference in SUVs of nipple in patients with dense and nondense breasts. There was no significant effect of age and menopausal status on SUVs of normal breast. However, there were trends of negative relationship, i.e., decreasing SUVs with increasing age. CONCLUSION: There was a significant difference in SUVs between the dense and nondense normal breast. However, the maximum SUVs in the dense breasts were well below the threshold of 2.5, a widely used cutoff value for malignancy. Menopausal status and age do not significantly affect the uptake of FDG.

Adult↗

PubMedDate not supplied

18-fluorodeoxyglucose positron emission tomography as a novel imaging tool for the diagnosis of aortoenteric fistula and aortic graft infection--a case report.

The diagnosis of aortic graft infection and aortoenteric fistula can be difficult to establish using conventional radiographic imaging modalities. Positron emission tomography (PET) imaging with 18-fluorodeoxyglucose (FDG) can rapidly provide anatomically clear images and define areas of inflammation with increased glucose metabolism. In this report the authors present a case of aortoenteric fistula diagnosed by FDG-PET. Early diagnosis led to rapid surgical intervention with graft removal and extraanatomic bypass. These encouraging results warrant larger controlled studies to evaluate the utility of FDG-PET in the diagnosis of prosthetic aortic graft infection.

Aged↗

PubMedDate not supplied

Early uncoupling of cerebral blood flow and metabolism after bilateral thalamic infarction.

Cerebral blood flow and metabolism may be uncoupled in the early phases after stroke onset. Prior reports of bilateral thalamic stroke have described subsequent coupling of blood flow and metabolism during the chronic stage. We chronicled the evolving relationship of blood flow and metabolism with concomitant single photon emission CT and positron emission tomography from the subacute to chronic phase following bilateral thalamic infarction.

Adult↗