Biomedical subjects

J M Woolfenden

Publications and source records attributed to J M Woolfenden.

43 records · Page 3Linked to original sources

PubMed1975

Scintigraphic elvaluation of liver metastases from thyroid carcinoma.

Thirty-one patients with carcinoma of the thyroid were evaluated using 131-I scan of the torso including the area of the liver. Focal areas of 131I uptake were found in the liver in two patients with follicular thyroid carcinoma. Both patients showed associated abnormalities on 99m-Tc-sulfur colloid liver scans. The remaining 29 patients showed either no uptake or a normal diffuse pattern of 131-I uptake in liver. Careful evaluation of the liver is recommended on the radioiodine body scan for metastases in patients with thyroid carcinoma.

Adenocarcinoma↗

PubMed1975

Evaluation of carcinoma of the cervix using 111In-bleomycin.

Indium-111 attached to bleomycin is useful in the scintigraphic localization of a variety of tumors. Since it does not normally accumulate in bowel and feces, it is superior to other radiopharmaceuticals, such as gallium-67 citrate, in the demonstration of abnormalities in the abdomen and pelvis. Twenty-eight patients with know carcinoma of the cervix were studied with whole body 111In-belomycin scans. Two "false-positive" scans were produced by local inflammation. Six "false-negative" scans were attributed to small tumors escaping scintigraphic detection. In the remaining 20 patients, scan findings correlated well with site and extent of the tumor as determined by other means. 111In-bleomycin scintiscanning may prove to be a highly useful adjunct in the evaluation of patients with carcinoma of the cervix.

Adenocarcinoma↗

PubMedDate not supplied

Asymptomatic hepatic mass in a 34-year-old woman.

Hepatomegaly was discovered on a routine physical examination of a 34-year-old, asymptomatic Mexican-American female. She was referred for a sonogram and a liver-spleen scan. Oral cholecystography was also requested.

Adenoma↗

PubMedDate not supplied

Rapid in vivo localization of a lost brachytherapy seed.

We adapted a small sodium iodide scintillation detector for rapid, in vivo localization of a lost brachytherapy seed. Using the detector, we were able to locate and remove an Ir-192 seed that was not visible to the unaided eye.

Brachytherapy↗

PubMedDate not supplied

Detection of small radiation sources: the effect of mode of count-rate presentation.

We used an observer-performance study to compare four different modes of presenting count-rate data from a radiation detector. Observers searched for small, concealed radioactive sources using a hand-held radiation-detector probe. The modes of count-rate presentation were a ratemeter, howler, multichannel scaler, and HRM III. The HRM III calculates the statistical significance of the difference between current and previous count rates and presents the result as an audio signal. We tested six observers with each mode of count-rate presentation, calculated receiver operating characteristic (ROC) curves, and used the areas under the ROC curves to compare the different modes. Observer performance was better with the multichannel scaler and HRM III than with either the ratemeter or the howler. The results suggest that observer performance with devices that use ratemeters or howlers can be enhanced by improving the mode of count-rate presentation.

Cobalt Radioisotopes↗

PubMedDate not supplied

Comparison of NaI(T1), CdTe, and HgI2 surgical probes: effect of scatter compensation on probe performance.

Spatial variation in the background source distribution makes tumor detection difficult for single-detector probes. Using a single energy window that brackets the photopeak helps discriminate against background events dominated by Compton scattering. Another approach is to use the information provided by an additional window in the Compton region. The performances of NaI(T1), CdTe, and HgI2 surgical probes have been compared under realistic simulations of a tumor-staging procedure using optimal single-sided energy windows and a two-window scatter-subtraction technique. Results showed that despite the differences in energy resolution of the detectors, the performances of the probes in a variable background were similar when optimal single energy windows were used. When the background variations were large, using information provided by a second window improved probe performance.

Cadmium↗

PubMedDate not supplied

Comparison of NaI(Tl), CdTe, and HgI2 surgical probes: physical characterization.

The physical properties of three surgical probes containing different radiation detectors are compared: a NaI(Tl) scintillator with a flexible, fiber-optic light guide, and two semiconductor detectors that operate at room temperature, CdTe and HgI2. Also compared are spectra, energy resolutions, and counting efficiencies measured at a variety of gamma-ray energies between 30 and 1000 keV. The energy resolution of the NaI probe is substantially poorer than that of either semiconductor probe due in part to light losses in coupling the scintillator to the fiber optics. The semiconductor probes have complex spectral response due to charge-carrier trapping and K x-ray escape, and not all photoelectric interactions in these detectors contribute to the useful part of the photopeak. Above 120 keV the counting efficiency for the NaI probe is an order of magnitude higher than for the CdTe and HgI2 probes. Both energy resolution and counting efficiency are slightly better for the HgI2 probe than for the CdTe probe.

Cadmium↗