Optimized beam planning for linear accelerator-based stereotactic radiosurgery.

Purpose: Current treatment planning for linear accelerator-based stereotactic radiosurgery and radiotherapy is a lengthy and iterative procedure. The planner has to manually select the beam arcs and carefully consider many different selections to ensure target volume coverage while sparing dose to critical organs. In this article we report an optimization procedure that can automatically select the beam arcs based on geometric and dosimetric analysis of the treatment parameters.

Mugwort and sage (Artemisia) pollen cross-reactivity: ELISA inhibition and immunoblot evaluation.

Background: Plants of the genus Artemisia are a source of fall allergic symptoms, particularly in the western United States. Studies have characterized the allergens in one of the major species (A. vulgaris) but currently there are no cross-reactivity data on the major United States species.

The prevalence of Dermatophagoides mite allergen in Colorado homes utilizing central evaporative coolers.

Objective: The prevalence of mite allergen was studied in homes in which the indoor relative humidity may be increased by use of an evaporative cooler.

Methods: Colorado homes in which central evaporative coolers are used and control homes were evaluated. ELISAs with monoclonal antibodies specific for Der p 1 and Der f 1 were performed on dust samples from each home in May and August.

Analysis of meteorologic variables and seasonal aeroallergen pollen counts in Denver, Colorado.

Background: The observation of low levels of weed pollens following a freeze and an early autumn snowfall in Denver, Colorado led to this analysis of meteorologic variables and pollen counts.

Objective: The purpose of this study was to examine, in depth, the relationship between observed pollen counts and a selection of independent meteorologic variables.

Methods: We prospectively studied in 1991 daily high and low temperature, relative humidity, precipitation, barometric pressure, percent sunshine, wind velocity and direction, tree, grass, and weed pollen, as well as dates of the first frost/freeze.

The exoscope--a frame-based video/graphics system for intraoperative guidance of surgical resection.

A system has been devised to focus a video camera mounted on a CRW stereotactic frame onto the surgical field and to integrate the video picture with a computer-generated three-dimensional view of structures or targets deep within the brain. The surgical resection can then be done with the surgeon looking either at the composite picture on the video/computer monitor (as in almost all endoscopic surgery) or at the surgical field, to perform the resection using the conventional techniques most comfortable to the surgeon and most effective for the resection. The graphics platform on which the Exoscope program is built is the same as used for the RSA X-Knife stereotactic radiosurgery system.

Dose-volume histogram computations for small intracranial volumes.

A sampling formalism is presented to accurately compute the absolute volumes and integral dose-volume histograms of small volumes treated in stereotactic radiosurgery. The presence of small volumes and sharp dose gradients places special constraints on the computational formalism and the accuracy required to compute the dose-volume relationships. We use a spatially nonuniform random sampling method to allow an efficient and accurate computation of the dose-volume histograms for an arbitrary number of volumes.

Aerobiology of the Colorado Rockies: pollen count comparisons between Vail and Denver, Colorado.

Pollen patterns were compared between Vail, CO (8,200 feet elevation), Aspen, CO (7,900 feet) and Denver, CO (5,280 feet) from 1984 through 1988. Counts were obtained at all sites with a volumetric intermittent cycling rotating impaction sampler. Aspen and Denver were compared in 1984, and Vail and Denver from 1985 through 1988.

Nondestructive investigations on ninety-seven surgically excised mammary prostheses.

The information contained in the medical files of 68 patients having undergone surgical excision of a total of 97 internal mammary prostheses allowed us to define a typical patient profile at time of first implantation. Age: 33 years 11 months, height: 1.59 m, weight: 51.

First observation of hopeïte and parascholzite in fibrous capsules surrounding silicone breast implants.

We observed mineralization in 32.6% of the capsular tissue of 97 mammary prostheses recovered after surgical excision. Three distinct mineralogical phases were identified.