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Biomedical subjects

R E Stanton

Publications and source records attributed to R E Stanton.

At least 19 recordsLinked to original sources
PubMed1997

Treatment planning for prostate implant with loose seeds.

A new method of treatment planning for the I-125 and Pd-103 permanent interstitial prostate implant is developed, which does not use the traditional nomograms but automatically generates optimized source configurations. An iterative algorithm is used that places one seed at a step. The volume dose of target is calculated at each step to determine the coldest spot where the next source is to be placed, so that the dose uniformity of target is best improved as source placement proceeds. At each step, the total activity required for the seed configuration as so established is calculated by normalizing the minimal dose to the prescribed dose. An optimized configuration is the one that takes the minimized total activity. Around its minimum the total activity has a very small variation with the number of seeds. Consequently multiple clinically acceptable seed configurations with similar total activity but different individual activities are generated simultaneously. In our computer generated treatment plans most of the seeds are distributed in the periphery of the target, similar to the Paterson-Parker pattern of a volume implant.

Humans↗
PubMed1981

The fontan procedure for tricuspid atresia.

A modified Fontan operation was performed on nine patients, ages 8--24 years (mean 14 years), with tricuspid atresia. The right atrium and right ventricle were connected with a valved conduit in five patients and directly in four. A porcine inferior vena caval valve was used in two patients. Prior operations had been performed in eight patients. There were no surgical deaths. Complications included pleural effusions, low-output syndrome, renal failure and atrioventricular block. There were two late deaths, only one of which was of cardiac origin. One patients required reoperation because of residual atrial septal defect at 1 month and again at 56 months for conduit stenosis. One patient required a pacemaker. Follow-up extends 6--65 months (mean 34 months). Survivors are clinically well and active, although four are taking medications. Postoperative cardiac catheterizations were done in six patients. Right atrial pressures were elevated in each, with no gradients across the conduit or pulmonary valve except in the one patient with conduit obstruction. Three patients had small residual ventricular septal defects and one a residual Blalock anastomosis. The Fontan procedure is an effective operation for tricuspid atresia. It may be further modified by establishing direct continuity between right atrium and right ventricle without a valve conduit in patients with a functioning pulmonary valve. The long-term ability of the right atrium to maintain adequate pulmonary flow and the effects of chronically elevated right atrial pressure on hepatic function and the cardiac conduction system must still be examined.

Adolescent↗
PubMed1979

A study of mammographic exposure and detail visibility using three systems: Xerox 125, Min-R, and Xonics XERG.

A breast phantom of novel design has been used to measure visibility of simulated calcific and soft-tissue fibrillar details in mammography, as well as to determine the roentgen exposure vs. depth. Exposure data were combined with a model of the breast as compressed during mammography to compute the mean exposure to the ductal parenchyma (MDE). Three different imaging systems were compared over a wide range of x-ray beam energies and breast characteristics. "Dosage" criteria other than the MDE are discussed.

Breast↗
PubMed1977

Long-term results of the Mustard procedure.

Over a 10-year period, 123 patients with transposition of the great vessels underwent the Mustard procedure. The hospital mortality for the series was 10.6%. There were seven late deaths, five of which were presumable due to arrhythmia. Sinus rhythm was noted postoperatively in 53% of the patients. Almost all the survivors had achieved catch-up growth when evaluated 6 months to 10 years later. A growth spurt was more consistently seen in the patients who were operated on under 2 years of age. Physical endurance and school performance were on a par with their normal peers or better in about half of the survivors. Severe neurologic problems were present in five patients. Postoperative catheterizations in 42 patients showed a rather high incidence of residual interatrial shunts, mild left ventricular outflow obstruction, and mild superior vena caval obstruction. Pulmonary venous obstruction and serious tricuspid regurgitation were not encountered.

Adolescent↗
PubMed1975

Pacemaker therapy in children with complete heart block.

Permanent pacemaker therapy in children with complete heart block is necessary occasionally. Ten patients ranging in age from 8 months to 15 years were treated with an implanted P-wave, synchronous epicardial pacemaker. Indications for implantation were persisting postsurgical heart block, congestive failure, syncopal attacks, and arrhythmias. There were two deaths not attributed to pacemaker malfunction. The remaining eight children have been followed up for 38 to 108 months. There have been 27 pulse generator replacements. Twenty-three were for battery exhaustion, three for electromechanical failure, and one was due to arrhythmia. Rhythm disturbances have occurred on eight occasions. There have been no infections. It is concluded that the implanted P-wave synchronous pacemaker is an effective method of therapy when indicated for children with complete heart block.

Adolescent↗
PubMed1975

An assessment of Mustard's operation as a palliative procedure for transposition of the great vessels.

Ten patients in whom palliative Mustard operations have been performed for transposition of the great vessels with ventricular septal defect and elevated pulmonary vascular resistance are reported. There has been early or late mortality in this group of patients, and postoperative morbidity has been minimal. Five of them have been recatheterized, and the results indicate substantial improvement in postoperative arterial oxygen saturation with change in pulmonary vascular resistance. The operation is reserved for those patients in whom peripheral desaturation is the major cause of symptomatology. Clinical improvement has been gratifying, and the continued use of the operation in selected patients seen indicated.

Adolescent↗