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Biomedical subjects

M Loyd

Publications and source records attributed to M Loyd.

4 recordsLinked to original sources

A comparative study of the costliness of Manitoba hospitals.

OBJECTIVES: In light of ongoing discussions about health care policy, this study offered a method of calculating costs at Manitoba hospitals that compared relative costliness of inpatient care provided in each hospital. RESEARCH DESIGN: This methodology also allowed comparisons across types of hospitals-teaching, community, major rural, intermediate and small rural, as well as northern isolated facilities. MEASURES: Data used in this project include basic hospital information, both financial and statistical, for each of the Manitoba hospitals, hospital charge information by case from the State of Maryland, and hospital discharge abstract information for Manitoba. The data from Maryland were used to create relative cost weights (RCWs) for refined diagnostic related groups (RDRGs) and were subsequently adjusted for Manitoba length of stay. These case weights were then applied to cases in Manitoba hospitals, and several other adjustments were made for nontypical cases. This case mix system allows cost comparisons across hospitals. RESULTS: In general, hospital case mix costing demonstrated variability in hospital costliness, not only across types of hospitals but also within hospitals of the same type and size. CONCLUSIONS: Costs at the teaching hospitals were found to be considerably higher than the average, even after accounting for acuity and case mix.

Bed Occupancy

A surface mold using iridium-192 seeds.

A radioactive mold for treating skin was constructed by embedding ribbons of iridium-192 seeds in bolus material. The mold was designed to match the treatment area outlined on the patient's skin. Computer-assisted pre-planning was performed to optimize the seed strength, number of seeds, and spacing of ribbons. An outline of the treatment area was transferred to the surface of a uniform slab of tissue-equivalent bolus material 1.3 to 1.4 cm thick and planned locations for the ribbons were marked. Seeds were loaded into the bolus material at a depth to place the sources approximately 1.0 cm from the skin. The resulting mold was flexible enough to conform to the patient's skin and the seeds were so tightly confined within the bolus that there was no possibility of loss. Isodose distributions for the mold on a flat surface agreed well with preplans. A velcro strap and neck collar were used to attach the mold to the anterior portion of the patient's neck. For situations in which radioactive surface applicators are desirable, the use of iridium-192 seeds offers uniform dose within a highly individualized treatment area.

Brachytherapy

Dose delivery error detection by a computer-controlled linear accelerator.

A commercial dual photon energy, computer-controlled linear accelerator has a complex collimation and beam delivery system. For accurate dose delivery, six separate motorized elements must be properly positioned for a given beam selection. Experimentally instituted misalignments of the primary electron scattering foils, the primary collimator, the flattening filter, the scattering foil carousel, and the backscatter shield or shutter produced significant dose delivery errors. The ability of the Mylar window monitor chamber to detect these errors was examined for x-ray beams. The fault detection system failed to interrupt dose delivery in a number of situations where the error in dose per monitor unit delivered ranged from -6% to +270% of the calibrated value.

Computers