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Biomedical subjects

L A Farber

Publications and source records attributed to L A Farber.

8 recordsLinked to original sources
PubMed1999

Dual time point fluorine-18 fluorodeoxyglucose positron emission tomography: a potential method to differentiate malignancy from inflammation and normal tissue in the head and neck.

Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies imaging FDG PET imaging is used to detect and stage head and neck cancers. However, the variable physiologic uptake of FDG in different normal structures as well as at inflammatory sites may either obscure a tumor focus or be falsely interpreted to represent tumor activity. Twenty-one patients (9 men, 12 women, median age 59) were scanned serially at two time points, one at 70 min (range 47-112) and the second at 98 min (77-142) after the intravenous injection of 4.3 MBq/kg of FDG. The mean interval between emission scans was 28 min (13-49). Transmission scans were performed and regions of interest (ROIs) were overlayed on the fully corrected images. Standardiued uptake values (SUVs) were generated for the cerebellum, tongue, larynx, every lesion, and a matched contralateral site. Follow-up and pathologic studies revealed 18 squamous cell carcinomas and nine inflammatory or infectious lesions. Tumor SUVs were 4.0+/-1.6 (mean +/- SD) for the first scan and 4. 5+/-2.2 for the second scan. Contralateral SUVs were 1.2+/-0.5 and 1. 1+/-0.5 for the two scans. Tumor SUVs increased by 12%+/-12% as compared with a 5%+/-17% decrease for contralateral sites (P<0.05). SUVs for inflammatory sites (2.0+/-0.7 and 2.0+/-0.9), cerebellum (4. 2+/-1.3 and 4.3+/-1.4), tongue (1.8+/-0.4 and 1.9+/-0.5) and larynx (1.5+/-0.6 and 1.5+/-0.6) remained constant over time (+0.6%, +2.8%, +1.4%, and -2.4%; P<0.05 when compared with tumor SUV changes). The ratio tumor/contralateral SUV increased by 23%+/-29% over time while this ratio for inflamed sites increased by only 5%+/-15% (P=0.07). The time interval between scans correlated with increase in SUV for tumors (r=0.55, P<0.05) but not for any of the other ROIs. Separation was superior when studies were performed more than 30 min apart (P<0.05). These preliminary data suggest that dual time point imaging compatible with a clinical study protocol is helpful in differentiating malignant lesions from inflammation and normal tissues, especially when separated by a sufficient time interval.

Diagnosis, Differential↗
PubMed1999

Detection of recurrent head and neck squamous cell carcinomas after radiation therapy with 2-18F-fluoro-2-deoxy-D-glucose positron emission tomography.

OBJECTIVES/HYPOTHESIS: Fluorodeoxyglucose positron emission tomography (FDG-PET) has been proposed as a sensitive method to diagnose and stage various malignancies. We assessed the efficacy of FDG-PET imaging in distinguishing tumor persistence/recurrence from posttreatment changes following radiation therapy for squamous carcinomas of the head and neck STUDY DESIGN: Retrospective analysis of FDG-PET results compared with biopsy results or outcome, or both. METHODS: Twenty-eight patients who had undergone radiation therapy with or without surgery for treatment of squamous cell carcinoma were studied with FDG-PET imaging. There was clinical suspicion for recurrence in each patient, but no obvious mass or lesion to biopsy was found on physical examination or anatomic imaging. The results of FDG-PET imaging were compared with those of biopsy or clinical follow-up of at least 6 months, or both. RESULTS: FDG-PET imaging was positive in 13 patients, and the presence of active disease was confirmed in 12. Two thirds of the 12 received further cancer treatment. There were 15 negative FDG-PET images. Thirteen of these were confirmed true-negative images, but two studies were false-negative images. The sensitivity and specificity of FDG-PET were 86% and 93%, respectively, with positive and negative predictive values of 92% and 87%, respectively. The overall accuracy was 89%. CONCLUSION: FDG-PET imaging is a useful modality to distinguish tumor persistence/recurrence from radiation-induced tissue changes in the neck following treatment for head and neck cancer. FDG-PET can identify patients who may benefit from further treatment, and may lead to improved outcome for individual patients.

Biopsy↗
PubMed1993

Circulating pancreatic polypeptide in patients with adenocarcinoma of the bile duct.

Using radioimmunoassay methods, the blood of patients with pancreatic tumors was screened for circulating polypeptide hormones. This screening discovered pancreatic polypeptide in abnormally high concentration in the serum of six of seven patients with adenocarcinomas of the bile duct. The assay appears to be very sensitive finding excessive residual pancreatic polypeptide production after palliative resections. Serum pancreatic polypeptide assays warrant evaluation as an aid in the diagnosis and management of patients with bile duct tumors.

Adenocarcinoma↗
PubMedDate not supplied

Application of intravascular brachytherapy: utilization of beta-irradiation source delivery systems within a community-based cardiac center.

PURPOSE: There are numerous clinical studies ongoing to assess the outcome, physics, and radiobiology of intravascular brachytherapy and its effect on the reduction of the rate of restenosis after balloon angioplasty procedures. The present study reports on the experience of two different delivery systems as utilized in the community hospital setting. METHODS AND MATERIALS: Patients were enrolled into one of four ongoing trials at our institution: the Novoste Beta-Cath trial, the Novoste Stents and Radiation Therapy trial (START), the Novoste START 40/20 trial, and the Guidant Intimal Hyperplasia Inhibition with Beta In-stent Trial (INHIBIT). The Novoste studies utilized the Novoste Beta-Cath System with 90Sr/Y, and the Guidant INHIBIT trial used 32P. Enrollments into the various trials were determined by inclusion and exclusion criteria specified by each protocol. Randomization was conducted per criteria as determined by the participating study protocol. RESULTS: Forty-two patients were enrolled in total. Thirty-four were included in the Novoste trials and eight in the Guidant study, according to availability of the trial. Assessment of practicality of treatment was dependent primarily on treatment duration and extension of time of catheterization procedures by the addition of intravascular radiation. Average dwell time within the Novoste trials was 3 min 40 s, and 7 min 46 s for patients in the Guidant study. No acute complications were observed in any of the trials. CONCLUSIONS: Intravascular brachytherapy can be performed in the community hospital setting without compromising the efficiency of balloon angioplasty procedures. Pending long-term outcome data and FDA approval for specific delivery systems, endovascular brachytherapy in community hospital cardiac catheterization laboratories can be realized in an efficient and timely manner.

Aged↗
PubMedDate not supplied

A dosimetric comparison of conventional vs conformal external beam irradiation of a stented coronary artery utilizing a new fluoroscopic imaging detector system.

UNLABELLED: Purpose. To determine whether conformal external photon beam irradiation may prevent or reduce the rate of restenosis of a stented coronary artery following percutaneous transluminal coronary angioplasty (PTCA). Optimal conformal external beam irradiation with limited cardiac dose requires adequate visualization of the stented vascular segment. With existing image intensifiers, identification of a coronary stent is poorly localized. We propose using an amorphous silicon panel detector to observe the movement of the stent during the cardiac cycle. BACKGROUND: Long-term radiation-induced coronary complications can be minimized by: (a) reducing the radiation field sizes, (b) fractionating the total dose over several days, and (c) applying multiple treatment beams. Localization of the movement of the stent during the cardiac cycle may allow for the design of radiation fields that conform to the stented vessel segment. This scheme may permit gating the radiation beam on or off relative to movement of the stent within or outside the radiation fields, respectively. METHODS: Using a new solid-state amorphous silicon planar detector, with a dynamic range of 12 bits, fluoroscopic images of a Palmaz-Schatz coronary stent were obtained. The stent was centered in a polystyrene phantom 20 cm thick and imaged using a 90-kVp, 3.5-ma, source-detector and source stent distances of 114 and 100 cm, respectively. With the solid-state silicon detector, the stent was identified in a single video frame (1/30 s). This fast image acquisition should allow for mapping the motion of the stent during the cardiac cycle. The stent movement during the cardiac cycle may then be correlated with the QRS complex in the electrocardiogram. CONCLUSIONS: The localization of a coronary stent during the cardiac cycle under fluoroscopy permits delivery of small conformal external radiation fields to treat stented coronary arteries, while minimizing radiation dose to surrounding normal cardiac tissue and vasculature. The best selection of treatment beam angles will be provided by high resolution fluoroscopic images of the stented region obtained from different beam directions. The three-dimensional movement of the stent, indexed in time with the QRS complex, will provide an important measure for gating radiation beams for conformal treatment delivery.

Angioplasty, Balloon, Coronary↗