Biomedical subjects

B A Gillies

Publications and source records attributed to B A Gillies.

7 recordsLinked to original sources

PubMed1995

Radiation protection design philosophy for a door interlock system for shared room remote afterloading brachytherapy.

A single remote afterloading system can sometimes be used for the radiation treatment of two or more patients in separate rooms simultaneously. This configuration poses certain radiation protection problems, especially in a busy clinic where some of the treatment rooms have to be used for other non-radiation related patients even though not all radiation treatments have been completed. In this report we describe a door interlock system that has been designed to allow for radiation protection purposes during radiation treatment but is disabled when the radiation treatment is completed--with enough safeguard built in to prevent accidental bypass of the interlock. In addition, the quality control procedures of the radiation monitor devices for these treatment rooms are described. These radiation protection procedures could be generalized to other remote afterloading systems.

Brachytherapy↗

PubMed1994

Fluorescent screen video imaging for checking linac beams in dynamic stereotactic radiosurgery.

Precise beam targeting is crucial to stereotactic radiosurgery. A monitoring system is described consisting of a fluorescent screen, video camera, and computer interface. Approximately ten frames are analyzed each second, verifying the beam intensity, uniformity, position, and diameter. When mounted on the gantry, the system can indicate the dynamic isocenter position using the "ball test" technique. The fluorescent screen video indicates that the 6-MV beam used for radiosurgery at our facility is acceptably stable; moreover, the small isocenter shift versus gantry and couch angles is reasonably reproducible. At our facility, quality assurance tests with this apparatus are performed every month.

Computers↗

PubMed1993

A local census of dementia sufferers.

The results of a census of all dementia sufferers known to institutional and community services in Angus are reported. A total of 859 sufferers were identified compared with an expected 1013 based on EURODEM prevalence rates. After allowing for cross-boundary flow to institutions, it was estimated that the true identification rate was 80% (809/1013). Of the estimated total 1063 sufferers (including cross-boundary flow): 26% were in hospital, 27% in residential or nursing homes, 27% in the community and known to services (often the GP), and 19% in the community and not known to services (or, at least, not returned by them in the census). With the co-operation of all concerned, a census approach can yield useful information at a much lower cost than a full survey.

Age Factors↗

PubMed1986

Effects of phthalic acid esters (PAEs) on the neonate and aspects of teratogenic actions.

A review of the literature reveals that several different phthalic acid esters (PAEs) are capable of causing testicular damage. Phthalate-induced zinc deficiency is consistent with germinal epithelial damage. Among experimental animals, mice perhaps show the greatest sensitivity to phthalate-induced terata, but high doses/exposure are required. Little toxicologic information is available with regard to phthalate-induced effects upon the neonate.

Animals↗

PubMed1983

Chronic intraperitoneal administration of fluids in rats.

A simple method for continuous long-term intraperitoneal administration in rats was devised. Polyethylene tubing was inserted into the peritoneal cavity through an incision in the abdominal wall just below the rib cage. The other end of the catheter was then guided subcutaneously toward an incision located in the back of the neck. The external opening of the catheter was blocked with a small piece of stainless steel wire. The indwelling intraperitoneal catheter permitted instillation of various solutions in rats four times daily for up to 94 consecutive days without apparent stress or pain on the treated animals. The catheter remained patent for the duration of the study in 39 of 60 (65%) rats.

Animals↗

PubMedDate not supplied

Radiosurgery with unflattened 6-MV photon beams.

One of the major drawbacks to doing stereotactic radiosurgery with a linear accelerator is the long time required to deliver the target dose. Single fractions of 25 Gy delivered at the isocenter and at depth in the skull may require beam times in excess of 15 min for a typical linear accelerator with a maximum dose rate of 250 cGy/min in tissue. In an effort to decrease the treatment time for this technique, the flattening filter has been removed from an AECL Therac-6 linear accelerator and the characteristics of the resulting beam have been measured. Flatness is acceptable for the field sizes used with this technique and the dose rate is increased by a factor of 2.75.

Brain Diseases↗

PubMedDate not supplied

Engineering modifications for dynamic stereotactically assisted radiotherapy.

To perform dynamic stereotactic radiotherapy, a number of modifications to the commercial linear accelerator were required and these are described in this report. A couch drive system was added to rotate the couch in synchrony with the gantry. A high dose rate beam for this technique is acquired through a head modification, which allows easy removal of the radiation field flattener. Because of these modifications, a number of changes and additions were required to the linac interlock system, including a complete new chain of interlocks for use with the stereotactic technique.

Biomedical Engineering↗