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Biomedical subjects

L W Gumerman

Publications and source records attributed to L W Gumerman.

12 recordsLinked to original sources
PubMed1988

Stereotaxic intracavitary irradiation for cystic craniopharyngiomas.

Stereotaxic intracavitary irradiation with instillation of phosphorus-32 (32P) colloidal chromic phosphate was performed in nine patients with cystic craniopharyngiomas. Serial neurological, ophthalmological, neuroendocrinological, and radiological examinations were performed before and after treatment. Dosimetry was determined based on a computerized tomography (CT) estimation of tumor volume, and was calculated to provide a tumoricidal dose (200 to 300 Gy) to the cyst wall. The follow-up period ranged from 14 to 45 months (mean 27 months). After treatment, all nine patients showed improvement of symptoms and radiological evidence of cyst regression. Because of an expanding solid component producing recurrent symptoms, one patient required a craniotomy 14 months after isotope instillation. Three of five patients with impaired visual acuity before surgery had significant improvement in acuity after treatment. Preoperative visual field defects in eight patients improved in four after 32P therapy. Of seven patients with preoperative endocrine abnormalities, one individual showed almost complete normalization and another had improvement in endocrine function. Patients who exhibited residual neuroendocrine function before isotope instillation developed no significant deterioration in endocrine status during the follow-up period. The findings suggest that stereotaxic intracavitary irradiation is a safe and effective treatment which should be considered as the initial surgery for cystic craniopharyngiomas.

Adolescent↗
PubMed1985

Comparison of computerized tomographic and radionuclide methods in determining intracranial cystic tumor volumes.

The dosimetry of radioactive phosphorus (32P) for intracavitary treatment of cystic brain tumors is dependent upon accurate determination of the cyst volume. The authors have used both high-resolution computerized tomography (CT) scanning and an isotope dilution technique with technetium-99m (99mTc) sulfur colloid to determine cyst volumes in an experimental model and in six patients with intracerebral cystic tumors. In six separate comparisons using an experimental phantom "cyst," no significant differences between CT and 99mTc values were detected. In six patients with cystic neoplasms varying from 3 to 6.7 ml in volume, the percent differences between values obtained by CT and isotope dilution ranged from -17.26% to +13.13%. In individual patients, these differences proved to be of little significance for planning dosimetry. In both experimental and clinical trials comparing isotope dilution and CT measurement techniques, the CT technique using the standard software of the scanner and 5-mm thick slices proved to be a highly accurate method of determining cyst volume. The authors now base dosimetric calculations for intracavitary radiation with 32P on CT technique alone.

Astrocytoma↗
PubMed1979

Bone stress: a radionuclide imaging perspective.

Thirty-five college athletes with lower leg pain underwent radiography and radionuclide studies to rule out a stress fracture. Their asymptomatic extremities and 13 pain-free athletes served as controls. Four main patterns were observed: (a) sharply marginated scintigraphic abnormalities and positive radiographs; (b) sharply marginated scintigraphic abnormalities and negative radiographs; (c) ill-defined scintigraphic abnormalities and negative radiographs; and (d) negative radionuclide images and negative radiographs. Since the patients with the first two patterns were otherwise identical medically, the authors feel that this scintigraphic appearance is characteristic of bone stress in the appropriate clinical setting, regardless of the radiographic findings. A schema is proposed to explain the occurrence of positive radionuclide images and negative radiographs in the same patient, using a broad conceptual approach to the problem of bone stress.

Adolescent↗
PubMed1978

Experimental fracture healing: evaluation using radionuclide bone imaging: concise communication.

Radionuclide bone imaging was performed in a rabbit model to observe the course of fracture healing and to establish criteria for distinguishing nonunion and delayed healing from normal healing. Sequential gamma-camera images (with pinhole collimator) were collected and subjected to computer analysis. Five groups were established: a) control--immobilization; b) control--immobilization plus periosteal stripping; c) simple fracture--osteotomy; d) delayed union--osteotomy plus periosteal stripping; and e) nonunion--osteotomy, periosteal stripping and polymethyl methacrylate interposed between fracture fragments. Histographic representation of absolute count rates along rabbit tibias followed a predictable pattern in the simple-fracture and delayed-union groups. They differed only in the time of appearance of phases. The nonunion group demonstrated no recognizable sequential pattern. In this experimental model, serial bone scanning with quantitative data analysis has shown potential for indicating the course of healing in fractures and for serving as a guide to treatment.

Animals↗
PubMed1976

Splenunculectomy in recurrent thrombocytopenia.

A 13-year-old boy developed thrombocytopenic purpura in 1953 which improved during 4 weeks of cortisone therapy. Following 13 years of intermittent symptoms the platelet count was found to be 8,000/mul. After splenectomy the patient was asymptomatic for 8 years, but had a recurrence of symptoms and thrombocytopenia in 1974. An initial spleen scan with 99Tcm sulfur colloid was negative; but when repeated with a gamma-camera and shielded liver, a splenunculus was demonstrated. After splenunculectomy a rapid remission occurred, and the patient has been well for 13 months.

Adolescent↗
PubMed1976

Influence of dimercaprol on the early hepatic uptake of 111In-bleomycin in the BALB/c mouse.

Dimercaprol (BAL) administered 1 hr before 111In-bleomycin in the normal BALB/c mouse produced an early preferential hepatic loading of 111In-bleomycin without a loading of the spleen, skin, bone, or muscle. Liver-to-muscle ratios were increased about threefold under the influence of BAL. Liver (c BAL)/liver (s BAL) ratios also increased threefold at 3 hr whereas relative muscle uptake remained at about unity. Indium-111 chloride (colloid, pH 6.5) used as a control did not show a similar increase. The findings suggest that the kinetics and distribution of 111In-bleomycin in the normal BALB/c mouse can be influenced by pretreatment with BAL.

Animals↗
PubMedDate not supplied

Salivary scan after major ablative head and neck surgery with prediction of postoperative fistulization.

Patients with carcinoma of the head and neck undergoing major ablative and reconstructive procedures following periods of prolonged debilitation, chemotherapy, and/or radiation therapy have been identified as having a high risk for postoperative wound complication, most often infection. Does postoperative wound infection arise de novo, does infection result from failure of prophylactic antibiotic coverage, or is it the result of anastomatic salivary leak? To investigate the incidence of unrecognized salivary leak into the neck, 24 patients underwent salivary radioisotope studies using technetium 99m sodium pertechnetate from three to six days postoperatively. The isotope was administered early in the morning with drainage bags empty. Patients and the collection system were scanned for activity between four and six hours later. Nine patients had postoperative evidence of salivary secretion radioactivity in their drainage system. All of these patients developed transient wound infections or fistulas. The remaining 15 had no uptake in their collection systems and no wound complications. We suggest that the preliminary results from this noninvasive, simply administered study indicate that the infected surgical neck wound may be secondary to unrecognized postoperative salivary contamination. This technique can be used to provide early identification of potential wound infection. Alternatively, information generated by this kind of study may be valuable in predicting patients with the highest risk for postoperative infection, thereby offering guidelines for the use of perioperative antibiotic prophylaxis.

Head and Neck Neoplasms↗