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Biomedical subjects

D E Brown

Publications and source records attributed to D E Brown.

116 records · Page 7Linked to original sources
PubMedDate not supplied

On the steady-state drift conditions of a water calorimeter in clinical megavoltage photon and electron beams.

We have investigated the characteristic behavior of a water calorimeter in a clinical environment where the temperature is not strictly controlled. Since the ambient temperature plays a crucial role in the successful operation of a calorimeter, its effects were closely monitored. The results were compared with theoretical predictions based on a simple model of heat transfer by conduction. They were found useful in analyzing the radiation dose measurements. In particular, a relationship between the absorbed dose and the pre- and postirradiation thermal drifts was examined. Finally, some suggestions are made concerning the desirable conditions under which a water calorimeter may be operated.

Calorimetry↗
PubMedDate not supplied

A thermoregulated enclosure for controlling thermal drift in a radiation calorimeter.

The ability to control thermal drifts is essential in operating a calorimeter. We investigated a thermal enclosure, which envelops the calorimeter with temperature-regulated air, thus thermally isolating the calorimeter from the room. The desired temperature in the enclosure is controlled by a control circuit and a thermoelectric device, which works as a Peltier effect heat pump. In this report, the details of the enclosure design and construction are presented with actual performance evaluations.

Animals↗
PubMedDate not supplied

Absorbed dose calorimetry: bridge nulling and voltage analysis techniques.

A theoretical analysis is made of the conventional calorimeter approach utilizing a two-thermistor Wheatstone bridge--an approach which requires balancing the bridge by adjusting variable resistances. However, with the current availability of computers and digital precision measuring instruments, the conventional calorimeter approach can now be readily replaced by an automated, nonmechanical, electrical systems approach called differential calorimetry. The analytical theory outlining such an approach is also presented.

Calorimetry↗
PubMedDate not supplied

The Elmslie-Trillat procedure: evaluation in patellar dislocation and subluxation.

The Elmslie-Trillat procedure for correction of patello-femoral malalignment was evaluated in 27 knees in 22 patients with an average followup of 42 months (minimum of 24 months). Preoperative and postoperative pain and activity levels were recorded for all knees. The quadriceps angle was recorded in 22 knees preoperatively and in 19 knees postoperatively. Good or excellent results were obtained in 81% overall and in 91% of those knees with patella alta. The postoperative quadriceps angle (Q-angle) correlated with the result. Correction of 10 degrees or less was always associated with a good or excellent result. In contrast, all patients with a fair or poor result had Q-angles at 15 degrees or greater. The preoperative Q-angle did not correlate with the eventual result. We concluded that inadequate medial displacement of the anterior tibial tuberosity may lead to unsatisfactory results and that this may be avoided by intraoperative measurement of the Q-angle; that significant distal advancement of the tibial tuberosity is not required in patella alta; and that correction of the Q-angle to 10 degrees or less correlates with a good or excellent result from the Elmslie-Trillat procedure for treatment of patella subluxation and dislocation.

Adolescent↗
PubMedDate not supplied

Diagnostic and operative arthroscopy of the knee under local anesthesia with parenteral medication.

Arthroscopy of the knee under local anesthesia was performed on 102 patients for operative and diagnostic purposes between January and December of 1985. The procedures were performed on a same day basis without a pneumatic tourniquet. The operative record of each patient was reviewed to determine postoperative diagnosis and treatment. The data was matched to a patient questionnaire that measured individual reaction to local anesthesia. The effectiveness and level of patient acceptance of this anesthetic technique for operative arthroscopy was then evaluated. Ninety-one patients responded to the questionnaire, 82 of whom had prior anesthetic experience. Ninety-five percent of the patients had minimal or no discomfort during the procedure. Eighty percent indicated a preference for local anesthesia in the event of subsequent arthroscopy. No complications relating to the anesthetic agent were noted. Arthroscopy of the knee under local anesthesia for routine operative arthroscopy was found to be safe, reliable, practical, and to have a high patient acceptance rate.

Adolescent↗
PubMedDate not supplied

Designing a National Disaster Medical System.

The National Disaster Medical System (NDMS) is a partnership of private and public sectors to provide care to the victims of great disasters. The system is being developed as a voluntary cooperative effort of four major Federal agencies, State and local governments, and the American professional and hospital communities. A medical response component will include 150 disaster medical assistance units capable of clearing or staging operations in a disaster. Each unit will comprise three 29-person teams containing physicians, nurses, medical technicians, and support personnel and will include a 16-person unit command and support element. An evacuation component will be founded on the military aeromedical evacuation system, augmented by civilian aircraft and other transportation resources. A hospital component will enroll 100,000 pre-committed beds in hospitals throughout the nation. The system is designed to care for up to 100,000 casualties arising from a massive peacetime disaster or an overseas conventional military conflict. The National Disaster Medical System will be implemented over a period of 3 to 5 years. The authors recommend that all parts of the American health care community join in support of the system.

Disaster Planning↗