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Biomedical subjects

A T Elliott

Publications and source records attributed to A T Elliott.

At least 19 recordsLinked to original sources
PubMed1996

UK nuclear medicine survey, 1992-93.

A postal survey of UK nuclear medicine departments was undertaken to collate information on equipment, numbers of procedures and staffing levels for the years 1992 and 1993. It was estimated that there are 235 sites undertaking nuclear medicine, the total number of procedures performed being some 490,000 in 1993 compared with 430,000 in 1989. Informal investigation suggests that the increase is due to greater usage of myocardial perfusion and lung ventilation/perfusion studies. Wide variations were noted in staffing levels, with only 22% of departments having medical cover of half-time equivalent or better: over 30% of departments have less than one consultant session per week. Approximately 20% of departments claimed to have no physics input, with a further 20% having less than one session per week.

Health Personnel↗
PubMed1995

A reappraisal of current methods for the assessment of planar gamma camera performance.

This study reappraises the acquisition parameters defined by three current protocols for the specification of planar gamma camera performance. These are the manufacturer Standards of the National Electrical Manufacturers' Association [1] and the International Electrotechnical Commission [2], and the user-orientated protocol of the UK Department of Health (DoH, formerly DHSS) Gamma Camera Performance Assessment Group [3]. The study looks specifically at three major planar performance characteristics: intrinsic non-uniformity, intrinsic spatial resolution and intrinsic non-linearity (spatial distortion). Acquisition parameters specified for these characteristics are investigated by testing a range of values for each parameter around those figures currently advocated by the three protocols. Those acquisition parameters which may be relaxed without loss of data integrity are identified and the adoption of revised parameters for some measurements within the DoH assessment protocol is suggested. Reviewing the data obtained, observations are made regarding the accuracy of some tests performed regularly for quality control purposes. The feasibility and advantages of incorporating some suitably modified DoH performance assessment tests within a routine quality assurance protocol for the gamma camera are also discussed.

Gamma Cameras↗
PubMed1994

Meta-analysis.

Explore the source record for details and available documents.

Bias↗
PubMed1993

The design and construction of a central radiopharmacy.

Following an inspection by the Medicines Control Agency (MCA) of the existing radiopharmacy, it was necessary to design and build a new facility at the Western Infirmary to supply radiopharmaceuticals for patient use throughout the West of Scotland. This is one of the largest radiopharmacies in Europe, supplying some 40,000 patient doses per year prepared using both closed and open procedures. The design parameters and construction details of the new facility are presented.

Facility Design and Construction↗
PubMed1993

UK nuclear medicine survey, 1989/90.

A postal survey of UK nuclear medicine departments was carried out to obtain information on activity during the year 1989/90. A rise of 14% in the number of administrations of radiopharmaceuticals was found compared to 1982: a rise of 22% in imaging studies was offset by a 30% decrease in the number of nonimaging investigations. The estimated total number of administrations in the UK was 430,000.

Humans↗
PubMed1991

An investigation of the magnitude and causes of count loss artifacts in SPECT imaging.

A quantitative evaluation and an investigation of the mechanism of the count losses that can occur in SPECT imaging is described. The most common clinical example of the artifacts which result from this is encountered when sections are taken through the femoral heads in skeletal studies of the pelvis. From some simple phantom studies, it was identified that the count losses were associated with the presence of a high dynamic range in the projection data. Further information was obtained from simulation studies. It was found that the count loss phenomenon is caused by the combined effects of the presence of a high count density area and a structure with a relatively high attenuation level. An appreciation of the presence, magnitude, and mechanism of this effect is important if erroneous clinical findings are to be avoided. This is particularly relevant because of the existence of a variety of techniques that can be used to remove the resulting artifacts.

Bone and Bones↗
PubMed1990

Simultaneous measurement of left ventricular function and perfusion.

A new radiopharmaceutical, methylisobutyl isonitrile (MIBI), has been developed as a technetium-99m-labelled alternative to thallium 201 for myocardial imaging. By virtue of the high specific activity of 99mTc, some 600 MBq may be administered as a 0.3 ml bolus, permitting the acquisition of a first-pass nuclear angiogram at rest and at peak exercise. The agent was assessed in ten sequential patients referred for routine cardiac catheterisation, who also underwent an exercise electrocardiographic (ECG) test. Good quality nuclear angiograms, planar perfusion and tomographic perfusion images were obtained; the results correlated well with the catheterisation data. Of 30 myocardial segments for which wall motion was judged normal/abnormal from the nuclear angiogram, results concordant with contrast studies were obtained in 27 (90%). In the case of the 50 segments analysed from the perfusion images, concordant results were obtained in 43 (86%) from the planar studies and in 42 (84%) from the tomographic studies. All normal segments were classified correctly.

Adult↗
PubMed1990

Fifteen years of radiological protection experience in a regional radiopharmacy.

Radiological protection experience in a regional radiopharmacy, currently handling 28.5 TBq (770 Ci) 99mTc y-1, is reviewed for the period 1974-1988. The results of personnel monitoring have shown a downward trend (by more than a factor of two) in radiation exposure of individual staff members, despite the workload per person [6000 GBq (162 Ci) 99mTc y-1] remaining virtually constant. Adequate staff selection and training contribute to the reduction in dose. A significant reduction in dose to the eyes was achieved by installing lead glass screens in the radiopharmacy work stations, and tungsten syringe shields reduced radiation dose to the hands. The use of commercially available kits for producing 99mTc radiopharmaceuticals, rather than relying on in-house preparations that require more operator handling, has also contributed to reduction in radiation exposure. Internal contamination of staff members with 125I was markedly reduced when the practice of sub-dispensing high-specific activity solutions of the radionuclide was discontinued. Annual doses from external radiation currently average less than 6 mSv (600 mrem) to the trunk, less than 7 mSv (700 mrem) to the eyes, and 50 mSv (5 rem) to the hands. Internal contamination of personnel with 125I, 131I, and 99mTc, as detected by thyroid and whole-body monitoring, contributed less than 65 mSv y-1 (6.5 rem) to the thyroid gland and less than 0.1 mSv y-1 (10 mrem) to the whole body.

Humans↗
PubMed1990

Investigation of factors affecting adhesion of 99Tcm labelled colloids to glass vials.

Factors which may possibly influence the adhesion of 99Tcm labelled colloid to glass vials were investigated. Of five colloids studied, two protein-free tin colloids were affected most by the problem, some 12-18% being lost by adhesion to the glass vial when the colloid was left resting on the bench, or 60-87% when it was rotated for a period of 4 h. The proportion of activity which adhered to the vial was dependent on the time the product had been contained within it, whether on the bench or rotated. Two of the colloids, both of which contained protein, were affected only slightly by the problem, one being a tin colloid and the other a sulphur colloid. An antimony sulphide colloid, which contained no added protein, was virtually unaffected by the problem. The degree of adhesion was not related to the pH of the product, nor to the temperature at which the product was stored, nor to the tendency of the colloid particles to grow in size upon vigorous agitation.

Colloids↗
PubMed1989

A comparative study of the relative sensitivity and specificity of radiolabelled monoclonal antibody and computerised tomography in the detection of sites of disease in human malignant melanoma.

A monoclonal antibody raised against the high molecular weight melanoma antigen was labelled with indium-111 and injected intravenously into 25 patients with malignant melanoma. The results obtained from images at 24 and 96 h post i.v. administration of the antibody were compared with results obtained from computerised tomography studies with regard to detection of previously unrecognised sites of metastatic disease and apparent false positive localisation. Detailed study of the patients' clinical condition and detection rates using the two methods suggest that both methods detect approximately 80% of clinically and pathologically confirmed metastases. Of 62 known metastases, the antibody detected 50 (81%), with 17 false positive results. False negatives were most common in the lung. In eight patients the two methods were considered of equal value, in 10 the monoclonal gave a greater amount of clinically relevant information, and in seven the CT was superior. In three patients clinically significant metastatic lesions were detected by the radiolabelled monoclonal and had not been previously recognised either by CT scanning or on clinical grounds. No patients had any adverse reaction to the antibody and in the course of our study the dose of antibody was reduced from 20 mg to 200 micrograms with no apparent loss of sensitivity. In at least two patients uptake of the labelled monoclonal into tumour sites would have been adequate for effective targeted radiotherapy.

Antibodies, Monoclonal↗
PubMed1988

Angina pectoris during exercise--relationship to coronary anatomy and myocardial function.

We studied 34 patients with proven coronary heart disease to determine whether the presence or absence of angina pectoris during exercise testing was associated with greater disease, ST segment depression or fall in left ventricular ejection fraction. Angina pectoris was the limiting symptom in 19 and fatigue/breathlessness in 15 patients. Exercise time [421(31) vs. 455(64) s], ST depression [1.4(0.3) vs. 1.1(0.3)mm], fall in left ventricular ejection fraction [13(2) vs. 12(2)] and coronary score and fall in left ventricular ejection fraction [15(2) vs. 8(3), P less than 0.02]. The degree of ST segment depression correlated with the coronary score (r = 0.6) and fall in left ventricular ejection fraction (r = 0.5). ST segment depression but not angina pectoris during exercise predicted the extent of disease and its functional consequences.

Angina Pectoris↗
PubMed1988

A comparison of isometric exercise, cold pressor stimulation and dynamic exercise in patients with coronary heart disease.

Isometric exercise and cold pressor stimulation have been proposed as alternatives to dynamic exercise in the evaluation of patients with coronary heart disease. We evaluated all three, by gated radionuclide ventriculography, in 13 male controls and 44 male patients with coronary heart disease. In controls, mean left ventricular ejection fraction did not change during isometric exercise or cold pressor stimulation (64 +/- 2 to 63 +/- 2 and 63 +/- 3) but fell significantly in patients (56 +/- 1 to 53 +/- 1 and 53 +/- 1, both P less than 0.001). During dynamic exercise, mean left ventricular ejection fraction rose in controls (64 +/- 2 to 84 +/- 2, P less than 0.001) but did not change in patients (56 +/- 1 to 56 +/- 2). There was considerable overlap between the groups in the left ventricular ejection fraction response to isometric exercise and cold pressor stimulation; only dynamic exercise discriminated between them. Isometric exercise and cold pressor stimulation are of little value in the diagnosis of coronary heart disease by radionuclide ventriculography.

Adult↗
PubMed1988

Automated radiopharmaceutical dispensing.

An automated workstation, developed for clinical biochemistry, has been evaluated for potential use in preparing radiopharmaceuticals. It was found that substantial modifications, both hardware and software, would be required but the approach seemed feasible.

Equipment Design↗