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Biomedical subjects

R Edward Coleman

Publications and source records attributed to R Edward Coleman.

63 records · Page 4Linked to original sources

Clinical PET in Oncology.

The major utilization of clinical PET is in oncology, and oncologic PET utilizes FDG as the radiopharmaceutical. FDG imaging demonstrates the increased metabolism by malignant cells compared to normal cells. The initial clinical application of FDG-PET was demonstrated in brain tumors, and the gradation of accumulation of FDG related to the degree of malignancy. Subsequent studies have documented the accuracy of FDG-PET in detecting and staging several different malignancies. Whole-body imaging has made a major impact on the ability of PET to document the distribution of malignancy.FDG-PET imaging is very accurate in determining if an indeterminate solitary pulmonary nodule is malignant and in staging lung cancer. The cost-effectiveness of PET has been demonstrated for these indications. Third-party payers have policies for paying for PET scans performed in the evaluation of solitary pulmonary nodules and in staging lung cancer. The preliminary data on the use of FDG-PET imaging in other malignancies supports its use in detecting liver metastases from colorectal cancer and differentiating fibrosis from recurrent tumor after therapy for colorectal cancer; staging the axilla in primary breast cancer; staging melanoma and lymphoma; and staging and detecting recurrence of head and neck cancer. The initial reports on the use of FDG-PET are encouraging in its use in musculoskeletal malignancy, ovarian cancer, pancreatic cancer, and thyroid cancer.

Journal Article↗

Serial Evaluation of Increased Chest Wall F-18 Fluorodeoxyglucose (FDG) Uptake Following Radiation Therapy in Patients With Bronchogenic Carcinoma.

PURPOSE: Following radiation therapy for bronchogenic carcinoma, increased FDG accumulation within the irradiated tissue can be identified. This finding has not been well characterized. Therefore, we retrospectively evaluated the time course, frequency, and intensity of increased FDG uptake over a one-year period in patients who had been treated with radiation therapy. MATERIALS AND METHODS: Serial FDG-PET studies (n = 38) were performed in patients (n = 12) with bronchogenic carcinoma before and after radiation therapy. Regions of interest (ROIs) were placed in the chest wall and activity concentrations of posttherapy studies were compared to pretherapy studies. FDG uptake was also described qualitatively relative to mediastinal activity (1-4 scale) by two observers blinded from clinical information. RESULTS: Chest wall radiation port ROI uptake was 18% higher in the 2-month (P = 0.08), 40% higher in the 6-month (P = 0.003), and 32% higher in the 12-month (P = 0.04) posttherapy studies than in non-port ROIs. In 6 patients that clinically had radiation-induced chest wall fibrosis or pneumonitis, visual interpretation identified abnormal chest wall or pleural region FDG uptake in 5/6. In 2/6 patients without clinical chest wall fibrosis, abnormal, chest wall FDG uptake was seen. CONCLUSIONS: Radiation therapy occasionally causes modestly increased soft tissue FDG uptake within irradiated soft tissue in patients being treated for bronchogenic carcinoma, which persists for up to one year after therapy.

Journal Article↗

3'-Deoxy-3'-[F-18]fluorothymidine positron emission tomography in patients with recurrent glioblastoma multiforme: comparison with Gd-DTPA enhanced magnetic resonance imaging.

INTRODUCTION: The accumulation of 3'-deoxy-3'-[F-18]fluorothymidine (FLT) on positron emission tomography (PET) images in patients with glioblastoma multiforme was evaluated and correlated with gadopentetate dimeglumine (Gd-DTPA) enhancement in magnetic resonance images (MRIs). METHODS: FLT studies in 10 patients with recurrent glioblastoma multiforme were retrospectively investigated. Dynamic emission data were acquired for 60 minutes immediately after injection of FLT. The standardized uptake value (SUV) for tumor and reference tissue (contralateral hemisphere and ipsilateral cerebellum) was calculated. The volumes of the metabolically active part of the tumor (V (PET)) and that of the Gd-DTPA enhancing part of the tumor (V (MR)) were calculated. RESULTS: FLT uptake in tumors peaked before 5 minutes and sometimes as early as 0.5 minutes, and reached a constant level at approximately 10 minutes after injection. The reference tissue time-activity curves had an early peak and reached a constant low background level. All tumors had increased FLT uptake and showed Gd-DTPA enhancement. The SUV in tumor was significantly higher than that in the reference tissue (P<0.0001). A significant correlation between V (PET) and V (MR) was found (P<0.0001) although there was a difference in the areas of Gd-DTPA enhancement and FLT uptake. CONCLUSION: These preliminary results indicate that FLT-PET may be useful for the detection of recurrent glioblastoma multiforme. Our data in a relatively small patient population do not support a clear-cut relationship between FLT accumulation and Gd-DTPA enhancement. Further pathologic correlation will determine if it can be used for detecting recurrent tumoral disease.

Adult↗

Positron emission tomography with 2-deoxy-2-[(18)F]fluoro-D-glucose for evaluating local and distant disease in patients with cervical cancer.

PURPOSE: To assess the accuracy of positron emission tomography (PET) with 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) for evaluating local and distant disease in patients with cervical cancer. METHODS: The PET imaging database maintained at our institution was used to identify patients who received FDG-PET scans for the clinical indication of cervical cancer for the past four years. Patients were followed for a minimum of six months following the PET study. Results of the FDG-PET studies were correlated with surgical pathology, biopsy results, and/or clinical follow up to assess the accuracy of FDG-PET in evaluating local and distant disease. RESULTS: A total of 61 FDG-PET studies performed in 41 patients were included in this retrospective study. Nine FDG-PET studies were performed for initial staging of cervical cancer, and 52 PET scans were performed in 35 different patients as restaging studies following therapy. For the initial staging, the local primary disease was identified in all nine FDG-PET studies, and PET distinguished the patients which had localized disease (four patients) from those with distant metastases on follow-up (five patients) with 100% accuracy. For restaging cervical cancer, FDG-PET had a sensitivity of 0.82 and specificity of 0.97 (accuracy 0.92) for evaluation of local recurrence. For evaluating distant disease in these patients, PET had a sensitivity of 1.00 and specificity of 0.90 (accuracy 0.94). In the evaluation of local disease, focal rectal activity caused false-positive results in two cases. Three false-positive studies for distant disease were caused by inflammatory adenopathy. CONCLUSION: FDG-PET is an accurate modality both for initial staging and restaging of patients with cervical cancer. PET is particularly sensitive for detecting distant metastases, allowing stratification of patients into those with locally confined disease and those with distant disease. These results were achieved by using a standardized PET imaging protocol without the use of bowel preparations, lasix administration, or Foley catheter drainage. Evaluation of local disease can be challenging due to adjacent rectal and bladder activity, and the use of hybrid PET/computed tomography (CT) scanners in the future may further improve evaluation of local disease.

Adenoma↗

PET and brain tumor image fusion.

PET imaging with (18)F-2-deoxy-2-fluoro-D-glucose (FDG-PET) is useful both for the initial evaluation of brain tumors and for follow up after therapy. Over 400 FDG-PET studies are performed at Duke University Medical Center annually for brain tumors. Image registration of FDG-PET data with anatomic imaging (MRI) is essential to accurately localize the abnormality in the brain because of the metabolic heterogeneity of brain tumors and the high background metabolism of normal cerebral cortex. A practical semi-automated image registration technique has been developed which is used routinely for all brain tumor patients. In the future, image registration will likely become increasingly important for FDG and other PET tracers used for brain tumor imaging, and the combined functional/anatomic information will be utilized directly for therapeutic radiation and surgical treatment planning.

Brain Neoplasms↗

Regional cardiac sympathetic innervation early and late after transmyocardial laser revascularization.

BACKGROUND: Prior experimental and clinical studies have drawn disparate conclusions regarding the effects of transmyocardial laser revascularization (TMR) on regional cardiac innervation in the treated regions. Regional afferent denervation has been proposed as a potential mechanism of action of the procedure, although this as yet remains unproven. The purpose of the present study was to evaluate regional myocardial sympathetic innervation both early (3 days) and late (6 months) after TMR. METHODS: Mini-swine in the early group were randomized to be sacrificed 3 days after holmium:YAG TMR (n = 5) or sham thoractomy (n = 3). In the late group, mini-swine with hibernating myocardium in the left circumflex (LCx) region were randomized to sham redo-thoracotomy (n = 5), TMR of the LCx distribution with a carbon dioxide (n = 5), holmium:YAG (n = 5), or excimer (n = 5) laser. Six months postoperatively the animals were sacrificed. Additional animals in both the early (n = 2) and late (n = 2) groups served as age- and weight-matched normal controls. Immunohistochemistry and Western blot analysis for tyrosine hydroxylase (TYR-OH), a neural-specific enzyme found in sympathetic efferent nerves and a commonly used anatomic marker of regional innervation, were performed on lased and nonlased LCx and septal regions. RESULTS: Immunohistochemical staining for TYR-OH was markedly diminished in the lased myocardial regions 3 days after TMR. This staining was significantly reduced compared to untreated septal regions, sham-operated, and normal LCx myocardium. Quantitative immunoblotting confirmed a significant reduction in TYR-OH (p < 0.05) protein concentration in the lased regions 3 days after TMR. On the contrary, TYR-OH staining was present in LCx myocardium surrounding the laser channels of all animals in all groups 6 months postoperatively. Staining was not different from controls. Similarly, there was no difference in LCx TYR-OH protein concentration between the normal, sham, or 6 months postoperative lased groups (p > 0.2 by one-way ANOVA). CONCLUSIONS: TMR-treated myocardium demonstrates anatomic evidence of regional sympathetic denervation 3 days postoperatively, although myocardium lased with each of the three lasers currently in clinical use is reinnervated by 6 months as evidenced by immunoblotting and immunohistochemistry for TYR-OH. These results suggest that mechanisms other than denervation may account for the long-term reductions in angina seen after TMR.

Analysis of Variance↗

Imaging of pheochromocytoma in 2 dogs using p-[18F] fluorobenzylguanidine.

p-[18F]Fluorobenzylguanidine ([18F]PFBG) is a norepinephrine analog that has been developed as a positron emission tomography (PET) imaging radiopharmaceutical. Myocardial sympathetic innervation, neuroendocrine structures, and tumors can be noninvasively imaged with [18F]PFBG. In this study, the uptake characteristics of [18F]PFBG were investigated in 2 dogs with a spontaneous pheochromocytoma. The extent of the pheochromocytoma was well documented in both dogs on the PET study. The standardized uptake values within the pheochromocytomas were greater than 25 by 10 min, and were 37 and 50 by 45 min in each dog. A third dog that was suspected to have an adrenal mass was also studied. In this dog, the [18F]PFBG study was normal. Surgical exploration and adrenal biopsy confirmed the [15F]PFBG imaging findings in both dogs. In each dog, there was rapid blood-pool clearance (within 10 min after intravenous administration of the [18F]PFBG), with high uptake specific within the myocardium and adrenal medulla. The results indicate that [18F]PFBG may be useful for imaging canine pheochromocytomas and aid in differentiating adrenal masses.

Animals↗