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A mobile tomographic gamma camera system, called Cardiotom Mark 1, has been developed for imaging the myocardium and other small organs. The Cardiotom system is based on a tomographic technique, ectomography, which is a limited view angle method using a rotating slant hole collimator (RSHC) and a stationary detector to produce projection images. This enables the ectomographic system to be implemented as a mobile system. With the system developed, almost 200 perfusion studies have been performed. The system is based on a second-hand detector and a 30 [degrees] RSHC. By segmenting the collimator, total system efficiency is increased and acquisition time can be reduced by a factor equal to the number of segments. The system developed is PC-based and totally self-contained with data acquisition, reconstruction, and image presentation. The mobility of the system and the fact that the examination requires no patient cooperation enable acute studies of myocardial perfusion in the critically ill patient, either in the intensive care unit or the emergency room. A mobile system with three-dimensional imaging can offer new possibilities in cardiological research and diagnosis. Index Terms - Acute studies, gamma camera, mobile system tomography.

A method for combined SPECT and transmission tomography has been developed for application to parallel collimator geometry. The technique is based on a specially designed, shutter operated device with radionuclide line-sources for the transmission studies. Simultaneous SPECT and transmission data acquisition can be made but cross-talk may disturb the two separate data sets. The present device operates with four 1 GBq, 40 cm long line-sources of 99|Tc.sup.m~. Using the same radionuclide for SPECT, emission data is acquired with the shutter closed. At the same angle, transmission data is subsequently acquired with the shutter open. In this case, the total acquisition time is prolonged and the transmission data has to be corrected before reconstruction. Using different emission and transmission photon energies, the shutter may be open during most of the SPECT acquisition time and closed only for collecting cross-talk correction data. Recent experiments have been performed with a transmission source with lower photon energy, 0.8 GBq 153Gd-line-sources (97 and 103 keV). Simulations of transmission data indicated that the activity of 153Gd might be about 2.5 times that of 99|TC.sup.m~ and about 6 times higher for 241Am for the same image noise. Simulations also showed that the total activity in uniform line-sources may be reduced without increasing the noise by chosing line-sources with an activity distribution that is average inversed to the photon transmission through the object.

To eliminate the occurrence of artefacts produced by clips on the CT images, the use of titanium clips is suggested. Tests in vitro and in vivo indicate that clips manufactured from 0.2 mm thick 99.9 per cent titanium do not cause artefacts. They are resistant to corrosion, nontoxic, effective, easy to handle, relatively cheap, and are visible on plain X-ray films. [ABSTRACT FROM AUTHOR]

A force platform with an auditory output consisting of two electronic balances was used to reinforce symmetrical body-weight distribution in stroke patients. Forty patients randomly assigned to an experimental group or a control group practised rising and sitting down for 15 min, thrice daily, 5 days a week for 6 weeks. The experimental group but not the control group received ground reaction force feedback through the auditory output. Vertical ground reaction forces under each foot were measured with two force plates. Mean difference in improvement of body weight distribution on the paretic leg was 13.2 +/- 10.7 (M, SD) per cent total body weight in the experimental group and 5.1 +/- 6.7 per cent in the control group in rising (p < 0.01) and 12.7 +/- 7.5 per cent total body weight and 4.6 +/- 6.6 per cent in sitting down tests (p < 0.001). The patients in the experimental group achieved in average close to a symmetrical body-weight distribution while rising and sitting down. Improvements in physical performance and sit-stand tests were greater in the experimental group (p < 0.05 and p < 0.01, respectively). No differences were seen in improvement in performance of activities of daily living. Symmetry in body-weight distribution in rising and sitting down correlated with high scores in physical performance, motor function in rising, and with functional ability.

A stereotactic system is described. It is built around a baseplate which is fastened to the head of the patient and to various diagnostic and therapeutic modalities. In principle this system can function as an interface between most diagnostic (CT scanners, PET scanners, conventional X-ray instrumentation for angiograms and pneumoencephalograms) and therapeutic (stereotactic instruments, linear accelerators) instruments. It has been in practical use since 1976 and used in a number of 'diagnostic-therapeutic' combinations.

Pelvic instability is a term widely used to describe a clinical entity characterized by pain localized to the pubic symphysis and/or sacroiliac joints. The pain often radiates down the leg. Hypermobility of the pelvic joints has been suggested as the cause of pain. Apart from several clinical stress tests, attempts at establishing objective evidence of such mobility have mainly consisted in radiologic measurement of motion of the pubic symphysis by a method which allowed only vertical movement to be recorded (5). In the present study symphyseal mobility was measured by an electromechanical method by which direct interosseous movement could be recorded in three directions and two different planes. Measurements were performed in a series of 15 patients with a tentative diagnosis of pelvic instability and the results compared to the results of radiologic measurement and to the normal values obtained in an earlier study of healthy volunteers (31). The results of this study would seem to refute the theory of symphyseal hypermobility being pathognomonic of so-called pelvic instability. It has moreover shown that radiologic measurement may be used for rough screening purposes, but is not sufficiently reliable for more exact measurements.

Two pins were inserted, one on each side of the symphysis in 15 volunteers and four cadavers. Movements between the pins were registered by two transducers. Symphyseal movements were small. Translations in the transverse and sagittal directions were around or below 1 mm. Rotations in the frontal and sagittal planes were below 1.5 degrees. Movements in the vertical direction were around 2 mm in both sexes. Higher values were observed in multiparous than in nulliparous volunteers.

A method for clinical studies of ground reaction forces during gait is presented. A walkway consisting of two force measuring platforms, each five meter long, allows the recording from several consecutive steps from both feet. Signals from photocells and goniometers have been added and a microcomputer system for on line recording and processing have been developed. The accuracy of the system is tested.