Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 122, December 1973

This special bibliography lists 343 reports, articles, and other documents introduced into the NASA scientific and technical information system in November 1973

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 138

This special bibliography lists 343 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1975

Image processing techniques in nuclear medicine

The application of image processing techniques to radionuclide images acquired on a gamma camera - computer system has been investigated. Hepatic perfusion imaging studies with 99Tcm-tin colloid were performed in patients with primary colorectal carcimma. The hepatic perfusion index performed poorly in the detection of those patients with occult or overt hepatic metastastes, as did mean transit times of liver colloid flow derived from deconvolution analysis. A discriminant function was developed which separated those patients with occult metastases from those without liver disease. A fully automatic algorithm to derive a left ventricular edge from each frame of an ECG gated cardiac blood pool study was developed and validated in patient studies. Left ventricular ejection fractions calculated from count rates within the edge were reproducible and correlated well with ejection fractions derived from the same images by a manual technique, and with ejection fractions derived from left ventricular cineangiography. Studies were performed in patients to evaluate the effectiveness of tomographic imaging of the myocardial perfusion imaging agent 99Tcm-tBIN for detection of ischaemic heart disease. Tomographic reconstructions in the planes of the axes of the left ventricle gave better results than transaxial reconstructions or planar imaging. Choice of the optimum reconstruction filter for use in tomography using 99Tcm-tBIN was examined by means of patient am phantom studies. These showed that more accurate diagnoses and better reconstructions were obtained with smoothing filters than by the use of sharp reconstruction filters. This work shows that optimum image processing techniques must be established to attain the best possible results with new radiopharmaceuticals for nuclear medicine investigations

Intracoronary ultrasound

Knowledge of the characteristics of the atherosclerotic plaque (eccentricity, composition, effect of initial dilatation or ablation) and of the flow modifications induced by a coronary stenosis would establish more precisely the severity of the lesion under evaluation, improve the planning and guidance of therapeutic interventions, and facilitate the detection of subsequent complications. The miniaturization of the ultrasound catheters a11d the de

Aerospace medicine and biology: A cumulative index to the continuing bibliography of the 1973 issues

A cumulative index to the abstracts contained in Supplements 112 through 123 of Aerospace Medicine and Biology A Continuing Bibliography is presented. It includes three indexes: subject, personal author, and corporate source

Aerospace Medicine and Biology: A cumulative index to the 1974 issues of a continuing bibliography

This publication is a cumulative index to the abstracts contained in supplements 125 through 136 of Aerospace Medicine and Biology: A Continuing Bibliography. It includes three indexes--subject, personal author, and corporate source

The clinical impact of multidetector SPET technology

Introduction: Single photon emission tomography (SPET) is an established technique in Nuclear Medicine. Recent advances in SPET technology have now permitted the development of multidetector gamma cameras. This thesis evaluates some of these new gamma cameras and their impact on clinical practice. Aim: (a) To assess four new multidetector SPET gamma cameras (IGE Neurocam, Toshiba GCA-9300A, IGE Optima and Sopha DST). (b) To establish appropriate acquisition and analytical clinical protocols. Methodology: For each instrument, the tomographic spatial resolution, contrast and sensitivity were measured. The capability of a new slant hole collimator (IGE Optima) to perform radionuclide ventriculography (RNV) was assessed. To evaluate the utility of these systems, a total of 1215 patient studies were performed (1007 cardiac, 85 skeletal, 73 renal and 50 brain studies). The effect of 8, 16 and 32 minutes data acquisition on image quality and clinical relevance was evaluated. In addition, a new cardiac SPET protocol for rest/stress myocardial perfusion scintigraphy (thallium-201/Tc-99m tetrofosmin) was tested. Results: Tomographic spatial resolution of the order of 10 mm FWHM was achieved by all four systems. System sensitivity was related to the number of detectors and ranged between 9.2–11.2 Kcps/(MBq/ml)/cm per detector. The slant hole collimator with cephalic tilt gave highly reproducible results (r=0.98,SEE=+2) for ejection fraction measurements in 75 patients. There was no significant difference in the clinical information obtained using 8 min, 16 min and 32 min acquisitions. Based on patient studies and experience with these multidetector SPET systems, optimum acquisition and analysis protocols for commonly performed SPET studies were documented for routine clinical use. Artefacts due to patient movement during Tl-201 myocardial SPET studies were less frequent on a dual-detector system compared with a single detector system (0.7% and 4% respectively); while artefacts due to poor positioning or shift in centre of rotation were more. The rest/stress thallium-201/Tc-99m tetrofosmin study protocol (acquisition and analysis) was completed in 90 min. This protocol gave a sensitivity of 80% and specificity of 70% for the detection of coronary artery disease. Conclusion: For the first time a comprehensive comparison of multidetector SPET systems has been documented. Optimum acquisition and analysis protocols have been identified. The study also shows that the new generation of multidetector SPET systems offer adequate resolution and sensitivity for routine clinical imaging. Increased sensitivity can be translated into an increased patient throughput. This can increase the cost-effectiveness of this new technology

A study of poststenotic shear layer instabilities

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