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Biomedical subjects

M Ginjaume

Publications and source records attributed to M Ginjaume.

10 recordsLinked to original sources

Estimation of peripheral dose from two linacs: Mevatron MX6700 and Mevatron KDS.

An empirical calculation method for high-energy beam peripheral dose estimation is described. The peripheral dose has been measured for a Siemens Mevatron MX6700 (6 MV) and a Siemens Mevatron KDS (6 and 18 MV) linear accelerators. The dose distribution is parameterized for each beam energy as a function of depth, distance from the edge of the field, and field size. A simple algorithm has been developed for dose calculation up to 100 cm from the field central axes. Predictions by this algorithm are compared with measurements in an Alderson phantom.

Particle Accelerators

Gastric emptying in marathon runners.

Radionuclide gastric emptying studies using 99m-Tc human serum albumin egg omelette have been carried out in 10 long distance runners at rest and during a 90 minute run at sustained speed. Resting values are compared with controls comprising 10 sedentary subjects. Runners show a significantly accelerated basal gastric emptying (runners t 1/2 = 67.7 (5.9) min; sedentaries t 1/2 = 85.3 (4.5) min, p less than 0.001). The exercise had no significant effect on gastric emptying in these trained subjects (exercise t 1/2 = 66.8 (5.9) min, p = NS), suggesting adaptation to exercise.

Adaptation, Physiological

Indium-111 antimyosin scintigraphy to assess myocardial damage in patients with suspected myocarditis and cardiac rejection.

Indium-111 antimyosin scans were used to assess myocardial damage in patients with suspected myocarditis and cardiac transplant rejection. The calculation of a myocardium to lung ratio (AM index) to quantify antimyosin uptake was performed. AM index in normal subjects (n = 8) at 48 hr postinjection was 1.46 +/- 0.04. In patients with suspected myocarditis (16 studies in 13 patients), AM index was 2.0 +/- 0.5 (p less than 0.001); suggesting a considerable incidence of ongoing cell damage in this group, despite the small proportion of positive right ventricular endomyocardial biopsy (RVbx) (4/13). In patients studied after cardiac transplantation (37 studies in 17 patients), AM indexes correlated with RVbx. In patients with RVbx proven rejection (n = 14), AM index was 1.87 +/- 0.19 (p less than 0.001). In patients with RVbx showing infiltrates but not myocyte damage (n = 13), AM index was 1.80 +/- 0.27 (p = 0.02). In patients with normal RVbx (n = 10), AM index was 1.56 +/- 0.17 (p = NS versus controls; p = 0.001 versus those with positive RVbx). Calculated AM indexes correlated with graded visual analysis of the scans (r = 0.823; p = 0.001). Antimyosin scans are an appropriate method to assess myocardial damage in patients with suspected myocarditis and cardiac rejection.

Adult

Lithium as an adjuvant of iodine-131 uptake when treating patients with well-differentiated thyroid carcinoma.

Differences in the I-131 uptake by 14 metastatic lesions from well-differentiated thyroid carcinoma and 12 local remnants of normal thyroid tissue before and after an adjuvant therapy with lithium carbonate, were observed. After the adjuvant treatment and administration of an I-131 tracer dose, a considerable increase of radioiodine uptake in all metastatic lesions was found (P less than 0.001), but only a slight increase was found in 50% of the normal tissue. The response to lithium carbonate by neoplastic tissue seems to be different than that of the normal thyroid tissue, and produces a lengthening of the average I-131 biologic life that could be helpful when treating well-differentiated thyroid carcinoma.

Adenocarcinoma

A comparison between four simple methods for measuring glomerular filtration rate using technetium-99m DTPA.

Numerous centers perform glomerular filtration rate (GFR) measurements on patients undergoing renal imaging with Tc-99m DTPA. GFR measurement, however, does involve multiple blood samples taken over a 4-hour period, and this has led to attempts to simplify the technique by reducing the number of blood samples required and hence diminish the time taken to perform the test and the inconvenience to the patient. Four different simplified techniques for measuring GFR that have been reported in the literature are compared with a reference 2 blood sample method. Three of the methods do not require any blood samples but have standard errors of greater than 20 ml/min in adults and greater than 14 ml/min in children. The other method requires one blood sample, and if this is taken at 2 hours postinjection, the standard error is 9 ml/min in adults and 5 ml/min in children. The latter method is suitable for routine use in renography when accuracy is not of paramount importance.

Adult