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Biomedical subjects

J A Deye

Publications and source records attributed to J A Deye.

12 recordsLinked to original sources
PubMed1995

Demographic characteristics of physicists who evaluate mammographic units.

PURPOSE: To determine whether there will be an adequate number of physicists to meet the 1996 American College of Radiology (ACR) Mammography Accreditation Program requirements and assess the qualifications of physicists available to evaluate mammography units as required by the federal Mammography Quality Standards Act of 1992. MATERIALS AND METHODS: A 21-question survey prepared by the ACR was sent to most medical physicists who perform evaluations of mammographic units. Replies were received from 1,011 individuals. RESULTS: Survey results are based on the replies of 824 individuals who indicated a willingness to perform evaluations in the future. In 1996, there will be approximately 510 certified physicists to evaluate an estimated 14,000 mammography units in the United States. CONCLUSION: A sufficient number of certified diagnostic medical physicists will be available to provide required annual performance evaluations of all mammography units in the United States only if the number of units evaluated per physicist increases substantially over current levels.

Data Collection↗
PubMed1990

ACR survey results: diagnostic imaging scientists and engineers.

The American College of Radiology's Committee on Physics Resources of the Commission on Human Resources conducted a survey of diagnostic imaging scientists and engineers to assess who is providing radiologic physics and related services in diagnostic imaging departments. The survey forms were distributed through the members of the American Healthcare Radiology Administrators. Survey results showed a predominance of M.S. and Ph.D. degrees in physics and medical/radiological physics. Nearly all respondents had their time split between numerous categories of work, such as clinical and research, and between different modalities such as diagnostic x-ray, nuclear medicine and radiation oncology. To enhance physics services in important areas such as CT, which currently receive little time, support is needed for work prioritization, for training, and for positions for physics and physics-support personnel.

Certification↗
PubMed1981

Neoplasia in fast neutron-irradiated beagles.

One hundred fifty-one beagle dogs were irradiated with either photons or fast neutrons (15 MeV) to one of three dose-limiting normal tissues--spinal cord, lung, or brain. The radiation was given in four fractions per week for 5 weeks (spinal cord), 6 weeks (lung), or 7 weeks (brain) to total doses encompassing those given clinically for cancer management. To date, no nonirradiated dogs or photon-irradiated dogs have developed any neoplasms. Seven dogs receiving fast neutrons have developed 9 neoplasms within the irradiated field. Of the neutron-irradiated dogs at risk, the incidence of neoplasia was 15%. The latent period for radiation-induced cancers has varied from 1 to 4 1/2 years at this time in the study.

Animals↗
PubMed1979

A nomogram for time-dose-fractionation factors.

Time-Dose-Fractionation (TDF) factors have been defined mathematically and listed in table form. A rapid reference, single-page nomogram representation of these factors is presented here.

Humans↗
PubMed1978

Electron contamination of a high-energy X-ray beam.

The Lorentz force on an electron is utilised to separate out the electron component from the open beam of a Clinac-18, operating in the X-ray mode. The experimental arrangement is such that the mixed beam (comprising the primary photons, the scattered photons and the contamination electrons) enters an external magnetic field, which is perpendicular to the central axis of the beam. The electron contribution is analysed as a function of collimator setting, depth and distance. Based on the data, one is led to believe that the shift in dmax with field size is due to a relative enhancement in the soft X-ray component as the collimator jaws are opened.

Electrons↗
PubMed1978

Experience with a pair of matched diodes for constancy checks.

A unit is discussed which employs a pair of matched silicon diode detectors to check the constancy of the output, beam quality, field flatness, and symmetry of teletherapy equipment. The unit has proven useful, but the long-term stability of the diode-amplifier system must be considered, because two years of experience has demonstrated significant sensitivity changes in the diodes.

Radiation Monitoring↗
PubMedDate not supplied

Empirical equation for tissue-maximum ratios/scatter-maximum ratios for indirectly ionizing radiotherapy beams.

A six-parameter equation has been fitted to the tissue-maximum ratio/scatter maximum ration (TMR/SMR) tables for 60Co, 4-, 6-, and 10-MV photon beams as well as the 35 MeV d leads to Be neutron beam. The empirical equation has been shown to fit the 60Co tissue-air ratio/scatter-air ratio (TAR/SAR) data equally well. The TMR/SMR model was developed from a three-parameter equation designed to eliminate the graphical extrapolation of zero-field size TARs.

Cobalt Radioisotopes↗