PubMed Health⌕ Search

Biomedical subjects

W J Howland

Publications and source records attributed to W J Howland.

6 recordsLinked to original sources
PubMed1977

Linearity of exposure with indicated time and current for diagnostic radiography units.

Quality control in diagnostic radiography begins with production of predictable exposures. The authors describe a technique which permits determination of the variation of mR/mAs for the entire diagnostic range of times and currents in only about 1 hour. The mR/mAs in newly installed units has been shown to vary by as much as +/- 50% compared to institutional acceptance levels of +/- 10%. Records of annual surveys and acceptance tests from 31 medical facilities, including 293 radiographic and fluoroscopic units, are reviewed, and effects of small variations in mAs on radiographic quality are shown.

Humans↗
PubMed1975

Limitations of bone scanning in clinical oncology.

Radioisotope bone scanning is frequently used as the major, and sometimes the only, diagnostic test for neoplasia in bone. While the evidence is convincing that bone scans are frequently more sensitive than roentgenographic bone surveys for detection of metastatic bone disease, there are false-negative results for a variety of reasons, and positive findings must be interpreted with caution. Scans also appear more limited than roentgenograms in their usefulness for evaluating changes in abnormal bone structure. Case histories and discussion are offered to indicate that usually both radioisotope bone scans and roentgenographic bone surveys should be obtained for initial screening and subsequent assessment of bone metastases.

Adult↗
PubMed1975

Postirradiation atrophic changes of bone and related complications.

The sequence of radiographically visible changes about the shoulder girdle following irradiation was analyzed in 49 patients who received 200 kV irradiation, in 50 who received 25 MeV betatron photon irradiation, and in 20 who received cobalt-60 irradiation. The changes were dose related and were most evident in the kilovoltage group, but also occurred following megavoltage therapy. Atrophic changes may be complicated by fracture, true necrosis, true osteitis or sarcoma. These atrophic changes have clinical significance similar to the atrophic changes that occur in skin and mucous membranes. The terms radionecrosis and radiation osteitis as applied to these changes should be abandoned since they imply a more serious process than is actually present. Biopsy should be avoided if possible since trauma and secondary infection could lead to true necrosis.

Atrophy↗