Biomedical subjects

R G Hoops

Publications and source records attributed to R G Hoops.

4 recordsLinked to original sources

PubMed1976

Lack of specificity for detection of breast lesions with radioactive cesium chloride.

Detection of breast disease at an early stage was evaluated with 131CsCl. The tissue distribution study showed that malignant tumors could be distinguished from both benign and normal tissue by the degree of 131Cs concentration. However, the external counting method was not sensitive enough to warrant general application to patients with a suspected malignant tumor of the breast. False-positive breast study findings using radionuclides, such as 131CsCl, require close follow-up study in view of possible malignant changes in benign disease of the breast.

Adenofibroma↗

PubMedDate not supplied

Measurements of the distribution of technetium-99m sulfur colloid and technetium-99m HEDP in normal humans.

Technetium-99m sulfur colloid and technetium-99m hydroxyethylidene diphosphonate (HEDP) are two radiopharmaceuticals that have been widely used in nuclear medicine. Radiation dose estimates for both materials have been published in the literature and are found in the package inserts of the commercial kits. However, these estimates were made without the benefit of quantitative human organ uptake data. Estimates of absorbed radiation dose to the kidneys differ by nearly a factor of 6 between the two calculations for HEDP. The results of this study are in agreement with the lower previous estimate. Other than that one exception, agreement of the previous estimates with the measurements reported here is surprisingly good.

Adult↗

PubMedDate not supplied

A system for quantitatively assessing certain performance parameters of gamma camera systems from reflective print and film transparency final images.

Past efforts at routine evaluation of gamma camera systems performance, using final product images, primarily resulted in qualitative assessments. This paper describes a system for quantitatively determining certain performance parameters of gamma camera systems using paper-backed print and transparent film test images of the same type used for viewing by the nuclear medicine physician. By use of appropriate transmission and line source phantoms, the gamma camera system's spatial resolution, distortion, and flood field uniformity as a function of position in the image field, are determined using a semiautomated image scanning and data reduction system. This system consists of a high-resolution scanning microdensitometer/reflectometer, interfaced to a computer, along with necessary programs to locate bar and line grid intersection points in the image. Also included are algorithms for calculating the various image parameters desired. This system may provide an analytical method for quantitatively assessing certain performance parameters of gamma camera systems, using the final-product images from the cameras.

Densitometry↗

PubMedDate not supplied

Calculations of total activity and relative radiolysis product yields for selected photonuclear reaction target systems used for production of clinically useful, short-lived, positron-emitting radionuclides.

The potential performance of certain photonuclear target systems designed to produce short-lived positron emitters for nuclear medicine applications was evaluated. Included were calculations of photonuclear target activity yields, relative radiolysis product yields and relative specific activities of products as a function of photonuclear target shapes, dimensions, spacing from the bremsstrahlung photon source, and the energy of the electron beam using the reactions 12C(gamma,n)11C, 14N(gamma,n)13N, and 16O(gamma,n)15O. Results indicate that substantial activity yields can be achieved in these photonuclear target systems and that specific activity of the product varies widely as a function of the energy of the electron beam used to produce the bremsstrahlung and the included angle from the central beam axis that the photonuclear target occupies. Results indicate that several commercial radiotherapy accelerators appear to have electron beam energy and current capabilities suitable for producing multiple mCi (1 mCi = 3.7 X 10(7) Bq) amounts of the above radionuclides.

Electrons↗