The role of the biomedical physicist in the education of the healthcare professions: an EFOMP project.

The role of the biomedical physicist in the education of the healthcare professions has not yet been studied in a systematic manner. This article presents the first results of an EFOMP project aimed at researching and developing this important component of the role of the biomedical physicist. A background to the study expands on the reasons that led to the need for the project. This is followed by an extensive review of the published literature regarding the role. This focuses mainly on the teaching contributions within programmes for physicians, diagnostic radiographers, radiation therapists, and the postgraduate medical specializations of radiology, radiotherapy, interventional radiology and cardiology. Finally a summary list of the specific research objectives that need to be immediately addressed is presented. These are the carrying out of a Europe-wide position audit for the role, the construction of a strategic role development model and the design of a curriculum development model suitable for modern healthcare professional education.

Radionuclide image minification can compensate for coarse digitization: concise communication.

Although it is common practice to digitize radionuclide images onto the finest matrix available, their low count densities and poor spatial resolution suggest that quite large pixels should be adequate. Observers find these large pixels visually obtrusive, but minification of the image can reduce this effect. Experiments reported here have investigated how minification (achieved by increasing viewing distance) affects the perceived quality of images digitized onto different sized matrices. Observers' subjective preference for different pixel sizes was measured at various viewing distances using clinical bone images as test patterns. An objective measure of image quality was made by comparing the detectability of computer-generated focal areas of increased activity both in simple noisy backgrounds and in clinical bone images. The results show that a 128 X 128 matrix is adequate when the image is 8 cm2 and is viewed from 1 and 2 m. A finer matrix failed to produce better results.

Cranial scintigraphy: value of adding emission computed tomographic sections to conventional pertechnetate images (512 cases).

A prospective trial was carried out to assess the contribution made by a radionuclide transverse-section view to conventional radionuclide scans of the brain. Each set of scans was reported by two independent teams of observers, but only one team viewed the tomography section. An abnormality rating was used to decide whether a set of scans was positive or normal. The reports for 512 patients were analyzed and compared with the final independent diagnosis. Greater accuracy of diagnosis with the section view was significant at the 0.1% level; the results showed that failure to detect tumors was almost halved while there was a 16% improvement for the detection of infarcts. Abnormality ratings were also used to plot ROC curves and rating curves; these showed that the addition of the tomographic view increased markedly the proportion of true positives without any increase in the proportion of false-positive reports.

Relationship between objective and subjective assessment of gamma camera image sharpness.

In order to relate the performance of the human observer to the objective specifications of a gamma camera system, images of a test object were taken under various conditions that could be expected to cause changes in resolution. Observers were asked to put the images in the order of increasing/decreasing sharpness. For the same physical conditions, objective measurements were made from which the resolution parameters FWHM and FWTM could be derived. By looking for significant differences in ordering of the images, it was possible to show that, within the limitations of the specific system investigated, a fractional change in FWHM of about 10% caused a significant change in image quality. Further experiments to test the universality of this figure are suggested.

Texture analysis in radionuclide tomographic liver imaging.

In clinical trials assessing the value of radionuclide tomographic liver imaging there has been no significant increase in diagnostic accuracy when conventional views have been viewed with tomographic images. In an effort to increase the diagnostic value of tomography, we have applied some simple methods of texture analysis to both phantom and patient tomograms in order to quantify different uptake patterns. Three algorithms were used which look at the differences between a pixel and its near neighbours. In phantom experiments, the variation of image texture with image noise was quantified. Accurate values of texture were obtained for images of the phantom containing various sizes of cold spots. Detection limits were then calculated for the different sizes of cold spots. It was found that 1.5 cm cold spots could be detected with a collection time of approximately 25 min, the usual collection time for livers being 20 min. The theoretical detection limits were checked experimentally and found to agree well with experimental values. A preliminary clinical survey was made applying texture analysis to eight images from normal livers and eight from abnormal (metastatic) livers. Although the sample was small, good separation between normals and abnormals was obtained.

Studies of the cavitational effects of clinical ultrasound by sonoluminescence: 4. The effect of therapeutic ultrasound on cells in monolayer culture in a standing wave field.

In previous work the phenomenon of sonoluminescence (SL) has been used to find the conditions in which transient cavitation during exposure to ultrasound is likely to be maximum. This paper reports the effect of therapeutic ultrasound on growth of mouse tumour cells in monolayer culture when the cells are insonated either at a pressure antinode or at a pressure node in a standing wave ultrasound field that is known to produce strong bands of SL at the pressure antinodes. Reduced cell numbers 72 h after insonation were recorded when the cells were insonated at an antinode but not when they were at a node. The possibility that this effect might be an artefact of the experimental system, and further experiments that could elucidate the nature of the damage, are discussed.

Modification of gallium-67 citrate distribution in man following the administration of iron.

Current imaging techniques with 67Ga citrate for the localization of malignant or inflammatory lesions have a number of major limitations. In an effort to improve the lesion-to-background ratio and to reduce the time between 67Ga citrate injection and performing the scan, the 67Ga citrate injection is now routinely preceded by injection of iron-sorbitol citric acid (Jectofer). A series of 147 patients has been studied and shows that (a) the diagnosis can be made at 24 h in 80% of the cases, and (b) when 24 h and 48 h images are read together, diagnosis is at least as accurate as by the standard method, which requires a 72 h interval between injection and scanning. The major differences in appearance are lower activity in the soft-tissue background, relative absence of colonic activity at 24 h and visualization of the bladder in about 40% of cases. We believe that by saturating the free transferrin with iron, uptake into soft tissues and bone is sufficiently modified to enhance the lesion-to-background ratio, thereby making earlier imaging and diagnosis possible.

An evaluation of transverse axial emission tomography of the brain in the clinical situation.

The Aberdeen section scanner provides, in addition to conventional views, a display of the distribution of radioactivity in a tomographic section of the brain. This paper examined the value of this additional information. Scans of lesions confirmed pathologically or radiologically, along with normal and doubtful cases, were examined after a careful randomization procedure. During the course of the study each set of conventional views was examined twice, once without and once with a tomographic section view. In two out of 29 cases (7%) the lesion was diagnosed only with the aid of the tomographic section scan. Improved accuracy of diagnosis with the tomographic section view was significant at the 1% level or better.

Characterization and use of a commercial n-type diode system.

The characteristics of n-type diodes (linearity, temperature, dose rate, radiation damage response, directional dependence, output factors, wedge factors and percentage depth dose determinations) were investigated. Subsequently, the diodes were used clinically for in vivo dose verification during external megavoltage photon beam therapy. It has been shown that n-type diodes are easy to use and the results obtained are comparable to those reported for p-type diodes. On most occasions, n-type diodes can be used without any additional correction factors apart from regular monthly calibration. There is good agreement between the uncertainty limits estimated from the diodes' characteristics and those obtained on the basis of 2261 patient measurements.

Sites of deposition of aqueous aerosols: a study of efficiency of delivery systems for lung ventilation imaging in man.

A study was made of the deposition of 99Tcm-DTPA aerosol in the components of a jet nebulizer-based aerosol production system. Three impaction devices were compared: a ball-bearing separator, a virtual impactor and a step separator. In addition a comparison was made of two types of tubing which carried aerosol from nebulizer to mouthpiece: corrugated and smooth-walled tubing. The retention of aerosol following inhalation was measured in five normal volunteers using different patterns of breathing. Using an aerosol production system which included a ball-bearing separator only a mean of 11% of the radioactivity loaded into the nebulizer was emitted as an aerosol. Some 18% remained in the ball-bearing separator. The ball-bearing and step separators produced similar total outputs (7% and 6% minimum), the step separator producing marginally higher mean output/min. The virtual impactor produced a lower output than the other two impactors studied, only 1%. A larger proportion of the aerosol output was deposited on corrugated tubing (7%) compared with smooth-walled tubing (1%). The retained fraction of the aerosol inhaled by subjects ranged from 16% to 43%. A higher fraction was retained when subjects inhaled deeply and held their breath for 10 s between each breath. The efficiency of radionuclide deposition from aerosol generator to patient ranged from 1.1% to 6% and was determined more by the retention in the subject than by choice of separator or tubing.

Identification of abnormal cells in short term monolayer cultures of human tumor specimens.

This work was undertaken to verify that when short term monolayer cultures are prepared from human malignant biopsy specimens, the cells which grow are tumor cells and not normal cells from the stroma. A wide range of human tissues, both normal and malignant, was used to obtain monolayer cultures and chromosome spreads were prepared by a modification of standard procedures. The cells were Feulgen stained and DNA values were obtained for cells arrested in mitosis. Metaphase DNA values for normal cells and for cells from a benign tumor were constant, close to the expected value relative to bull sperm, and showed little spread about the mean. Metaphases from malignant cells had abnormal mean DNA values, and generally showed much greater spread about the mean. Results confirm that for cells grown in vitro from tumor biopsies, those which are in the cell cycle and reach mitosis are abnormal and presumably malignant. This is evidence in favor of this type of short term culture as a method for studying the properties of human tumor cells.

A search for sonoluminescence in vivo in the human cheek.

In a previous experiment, sonoluminescence was observed in aerated water, especially at the pressure antinodes in the standing-wave field of a physiotherapeutic ultrasound device (Therasonic 1030). Mammalian cells in vitro showed growth inhibition when placed at the pressure antinodes but not at adjacent pressure nodes. In the light of these results, we looked for sonoluminescence in vivo when a similar standing-wave field was set up. To detect luminescence, a light guide was held against the inner surface of the human cheek. This would channel any luminescence photons to a cooled, red-sensitive photomultiplier which would quantify the light. Direct insonation of the cheek produced no detectable luminescence. Similarly when a water bag was placed against the outer surface of the cheek, and the latter was insonated through the bag, no luminescence was detected. Sonoluminescence from the water bag was, however, detected when the bag was placed against the inner surface of the cheek, showing that absorption of sound by the cheek tissue was not preventing cavitation. Further analysis showed that if cavitation had been occurring in the cheek without detection using the system employed, then the resulting sonoluminescence would have to be at most 0.025 times as intense as that produced by an equivalent volume of aerated water.

A strategic development model for the role of the biomedical physicist in the education of healthcare professionals in Europe.

This is the third of a series of articles targeted at biomedical physicists providing educational services to other healthcare professions, whether in a university faculty of medicine/health sciences or otherwise (e.g., faculty of science, hospital-based medical physics department). The first paper identified the past and present role of the biomedical physicist in the education of the healthcare professions and highlighted issues of concern. The second paper reported the results of a comprehensive SWOT (strengths, weaknesses, opportunities, threats) audit of that role. In this paper we present a strategy for the development of the role based on the outcomes of the SWOT audit. The research methods adopted focus on the importance of strategic planning at all levels in the provision of educational services. The analytical process used in the study was a pragmatic blend of the various theoretical frameworks described in the literature on strategic planning research as adapted for use in academic role development. Important results included identification of the core competences of the biomedical physicist in this context; specification of benchmarking schemes based on experiences of other biomedical disciplines; formulation of detailed mission and vision statements; gap analysis for the role. The paper concludes with a set of strategies and specific actions for gap reduction.

A comprehensive SWOT audit of the role of the biomedical physicist in the education of healthcare professionals in Europe.

Although biomedical physicists provide educational services to the healthcare professions in the majority of universities in Europe, their precise role with respect to the education of the healthcare professions has not been studied systematically. To address this issue we are conducting a research project to produce a strategic development model for the role using the well-established SWOT (Strengths, Weaknesses, Opportunities, Threats) methodology. SWOT based strategic planning is a two-step process: one first carries out a SWOT position audit and then uses the identified SWOT themes to construct the strategic development model. This paper reports the results of a SWOT audit for the role of the biomedical physicist in the education of the healthcare professions in Europe. Internal Strengths and Weaknesses of the role were identified through a qualitative survey of biomedical physics departments and biomedical physics curricula delivered to healthcare professionals across Europe. External environmental Opportunities and Threats were identified through a systematic survey of the healthcare, healthcare professional education and higher education literature and categorized under standard PEST (Political, Economic, Social-Psychological, Technological-Scientific) categories. The paper includes an appendix of terminology. Defined terms are marked with an asterisk in the text.