Biomedical subjects

J S Laughter

Publications and source records attributed to J S Laughter.

4 recordsLinked to original sources

PubMed2000

A variable resolution x-ray detector for computed tomography: II. Imaging theory and performance.

A computed tomography (CT) imaging technique called variable resolution x-ray (VRX) detection provides variable image resolution ranging from that of clinical body scanning (1 cy/mm) to that of microscopy (100 cy/mm). In this paper, an experimental VRX CT scanner based on a rotating subject table and an angulated storage phosphor screen detector is described and tested. The measured projection resolution of the scanner is > or = 20 lp/mm. Using this scanner, 4.8-s CT scans are made of specimens of human extremities and of in vivo hamsters. In addition, the system's projected spatial resolution is calculated to exceed 100 cy/mm for a future on-line CT scanner incorporating smaller focal spots (0.1 mm) than those currently used and a 1008-channel VRX detector with 0.6-mm cell spacing.

Algorithms↗

PubMed1986

Dental X rays found to have no effect on hearing aids.

Each of the two manufacturers supplied one pair of behind-the-ear hearing devices for testing. The control group had the volume turned off and the test group had the volume turned on fully. All units were subjected to a series of 21 exposures of 90kV(p) and 15 mA, resulting in cumulative doses of 5.465 to 5.516 R. All devices were analyzed for any changes that resulted from radiation exposure. Both vendors reported that no changes had occurred. For legal reasons, however, one vendor suggested that it would be best to remove the hearing device before exposure to radiation. Such prudent action might prevent the occurrence of a very unusual accident. A third company that conducted a similar experiment on its own units indicated that no changes had occurred. The company's testing facility also suggested that a vendor should not give any warranty and recommended the hearing aid device be removed before radiographic examination.

Hearing Aids↗

PubMed1985

A system for the study of behavioral thermoregulation of small animals.

A system suitable for the simultaneous monitoring of two unrestrained animals in separate thermoclines is described. It makes use of low-cost, field-proven components to: provide a graded convective and/or conductive temperature continuum over a relatively short runway; measure ambient temperatures at multiple locations within the thermocline; measure the body temperature of a free-running animal within the thermocline; localize the position of the animal within the thermal gradient; and print all the data at periodic intervals. Studies comparing the choices of thermal preference by guinea pigs under diverse conditions indicate that a satisfactory degree of resolution can be achieved by this system.

Animals↗

PubMed1979

A system oriented electrocardiographic amplifier.

A low noise, programmable gain amplifier has been developed for acquiring ECG data from a variety of recording environments. Features include: low noise (4muV peak-to-peak) differential inputs; digitally programmable gains (range 100 to 16000) and output DC offsets (range -3.5 to +4 V) controlled via a serial interface; externally selectable low frequency response (0.04 or 0.08 Hz); and an on-board output monitor multiplexer controlled via a second serial interface.

Amplifiers, Electronic↗