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S N Hack

Publications and source records attributed to S N Hack.

6 recordsLinked to original sources
PubMed1988

Dynamic ventilation scintigraphy: a comparison of parameter estimation gating models.

Two procedures for providing the synchronization of ventilation scintigraphic data to create dynamic displays of the pulmonary cycle are described and compared. These techniques are based on estimating instantaneous lung volume by pneumotachometry and by scintigraphy. Twenty-three patients were studied by these two techniques. The results indicate that the estimation of the times of end-inspiration and end-expiration are equivalent by the two techniques but the morphologies of the two estimated time-volume waveforms are not equivalent. Ventilation cinescintigraphy based on time division gating but not on isovolume division gating can be equivalently generated from list mode acquired data by employing either technique described.

Humans↗
PubMed1986

Acquisition of gamma camera and physiological data by computer.

We have designed, implemented, and tested a new Research Data Acquisition System (RDAS) that permits a general purpose digital computer to acquire signals from both gamma camera sources and physiological signal sources concurrently. This system overcomes the limited multi-source, high speed data acquisition capabilities found in most clinically oriented nuclear medicine computers. The RDAS can simultaneously input signals from up to four gamma camera sources with a throughput of 200 kHz per source and from up to eight physiological signal sources with an aggregate throughput of 50 kHz. Rigorous testing has found the RDAS to exhibit acceptable linearity and timing characteristics. In addition, flood images obtained by this system were compared with flood images acquired by a commercial nuclear medicine computer system. National Electrical Manufacturers Association performance standards of the flood images were found to be comparable.

Humans↗
PubMed1980

External quantification of myocardial perfusion by exponential infusion of positron-emitting radionuclides.

A technique was developed and evaluated using the exponential infusion of positron-emitting diffusible tracers to quantitate myocardial perfusion. The approach employs a parameter that rapidly reaches a constant value as a function of tracer delivery rate, isotope decay constant, and the monotonically increasing tissue radioactivity. Isolated rabbit hearts with controlled flow were used to evaluate the approach, because tracer kinetics in such preparations mimic those in vivo. Accordingly, exponential infusions of H2 15O and [11C]butanol were administered to 25 isolated rabbit hearts perfused with Krebs-Henseleit solution (KH) alone or KH enriched with erythrocytes (KH-RBC, hematocrit = 40). With flow varied from 1.2 to 5 ml/g per min in eight KH hearts infused with H2 15O, actual and estimated flow correlated closely (r = 0.95, n = 52 determinations). For the KH-RBC hearts, flow was varied from 0.3 to 1.5 ml/g per min. Actual and estimated flow correlated significantly for both the 14 KH-RBC hearts infused with H2 15O (r = 0.90, n = 89 determinations) and the 3 KH-RBC hearts infused with [11C]butanol (r = 0.93, n = 13 determinations). In addition, the required exponentially increasing arterial tracer concentrations were shown to be attainable in vivo in dogs and rhesus monkeys after intravenous exponential administrations of tracer. The results suggest that the approach developed employing exponential tracer infusion permits accurate measurement of myocardial perfusion and that it should prove useful in the noninvasive measurement of regional myocardial perfusion in vivo by positron emission tomography.

Animals↗
PubMedDate not supplied

Radiology engineering at the Albany Medical Center: five year's experience.

A Radiology Engineering program was initiated in the Department of Radiology at the Albany Medical Center, Albany, New York, in the summer of 1981. The program has been successful in attaining its goals of containing costs, providing minimal equipment downtime, and giving high-quality service. This report presents the job functions and duties that the department found necessary to provide this level of service. In addition, two techniques for managing malfunction and service reports, techniques for scheduling PM's and service calls, and software management tools that assist the department with service are described.

Biomedical Engineering↗