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Biomedical subjects

R Myerson

Publications and source records attributed to R Myerson.

9 recordsLinked to original sources
PubMed1989

Preoperative irradiation for rectal cancer. Improved local control and long-term survival.

Between July 1975 and July 1986, 112 patients with adenocarcinoma of the rectum were treated using preoperative irradiation followed by excisional surgery on the colorectal surgery service of Jewish Hospital at Washington University Medical Center in St. Louis. There were 68 men and 44 women in this study, with ages ranging from 19 to 94 years of age. In all cases, the rectal cancers were believed to be transmurally invasive based on initial clinical examination. Included in this group were 13 patients with poorly differentiated tumors and 51 patients with tumors fixed to surrounding tissues. Between 1975 and 1980, we used 2000 cGy preoperative irradiation followed by immediate excisional surgery to treat 22 patients. Excisional surgery for cure was divided between abdomino-perineal resection of the rectosigmoid in eleven patients, low anterior resection of the rectosigmoid in eight patients, and a low Hartmann's procedure in three patients. Five-year survival for 20 patients with potentially curable lesions (Dukes' A, B, and C), was 85%, and there was no local recurrence. Between 1980 and 1986, 90 patients were treated with 4500 cGy preoperative irradiation over a 5-week period followed by a 6-week waiting period, before excisional surgery. There were 72 patients with Dukes' A, B, and C lesions. Fifty patients underwent abdomino-perineal resection of the rectosigmoid, 33 patients underwent low anterior resection of the rectum, and seven patients underwent a low Hartmann's procedure. Five-year survival was 86%. Local recurrence was 1.8%. Tumor fixation and histologic dedifferentiation were the only factors that influenced survival. Five-year survival of patients with fixed poorly differentiated tumors was 27% as compared to 87% in patients with nonfixed well-differentiated tumors (p less than 0.0001). Tumor fixation was not a significant factor in itself. Preoperative external beam irradiation improves survival, local control, and resectability in patients with rectal cancer. This effect may be due to the treatment of the "tangential" margins and local lymph node metastases. Preoperative staging can be accomplished by determining fixation and differentiation of the tumor when preoperative irradiation is used.

Adenocarcinoma↗
PubMed1986

Spinal cord protection during radiation therapy.

Treating intrathoracic malignancies to high doses, particularly those of lung and esophagus, requires limiting the radiation dose delivered to the spinal cord. Several factors are important in determining the cord dose. These are: The distance from the block or collimator edge to the cord, the variation of dose with distance from the block or collimator edge and, the expected variation of this distance for clinical set-up from day-to-day. When treating with an oblique beam, the position of the cord may be difficult to identify. A technique for localizing the spinal cord on a simulator film at an arbitrary gantry angle is presented. The technique requires determination of distances from the central axis of the beam to the medial aspect of the pedicle and posterior vertebral body. These can readily be obtained from measurements on orthogonal, AP/PA and lateral isocentric simulator radiographs. A mathematical transformation is applied to determine the corresponding cord locations on the oblique radiographs for any arbitrary gantry angle. The accuracy of cord localization was within 2-3 mm with a precision of 2 mm for five physicians who used this technique. The beam edge characteristics for 60Co, 6 MV, and 10 MV teletherapy unit were measured for various depths and field sizes. For the 6 and 10 MV units, the beam penumbra is nearly independent of the field size, depth and field defining devices (inner and outer collimator jaws, trimmer bars, and shielding blocks). Because the beam penumbra is dependent on the design of the linear accelerator, its measurement should be made individually for each linear accelerator. Our preliminary data on patient positioning uncertainty did not exceed the 6-8 mm limit documented in the literature.

Humans↗
PubMed1985

Bilateral language: is the left hemisphere still dominant?

A 13-year-old left-handed boy with a left fronto-parietal vascular malformation evidenced bilateral symmetrical language representation at intracarotid amytal testing. Surgical resection of the parietal motor and frontal premotor area (sparing classical perisylvian language regions) for seizure control resulted in an acute aphasia. Language deficits were still apparent 3 months and to a lesser degree 1 year after surgery. This suggests that when language is bilateral and symmetrical, the left hemisphere may still be dominant or both hemispheres may be necessary to sustain full language competence. Explanations for atypical language localization within the left hemisphere are also discussed.

Adolescent↗
PubMed1965

Hepatic coma.

Explore the source record for details and available documents.

Hepatic Encephalopathy↗