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A prospective survey was performed in 17 nuclear medicine departments during 1996 in an attempt to provide reliable data on the prevalence of adverse reactions to radiopharmaceuticals. All adverse events following radiopharmaceutical administration were recorded, irrespective of the severity or likelihood of causality, and subsequently analysed using an algorithm developed by Silberstein et al., designed to establish a cause-effect relationship. A prevalence of 11 events per 10(5) administrations was obtained (95% confidence limits 3.3-19.2). No serious of life-threatening events were reported. This rate is slightly higher than that obtained in a larger scale study in the United States (2.3 events per 10(5) administrations, 95% confidence limits 1.2-3.4). The difference may be due to the decision to include or exclude vasovagal events from the analysis, the way in which the algorithm was used and the comparative size and time scale of the two studies. The prevalence of adverse reactions is approximately 1000-fold than less that occurring with iodinated contrast media and drugs.

The low energy X-ray emissions of 123I lead to large variations in activity measurements using an ionisation chamber. A copper filter 0.5mm thick removes these X-rays but only reduces the 159 keV emissions by 14%. However the ionisation chamber needs to be recalibrated for the copper filter attenuation. We outline a simple method using a measurement made on 99Tcm to determine the change in sensitivity of the ionisation chamber using the copper filter. With the copper filter, the variation of activity measurements when 123I is in a syringe compared to those in a vial is reduced from 80% to 3%. The ratio of the manufacturers stated activity to measured activity was 102% and 111% for two manufacturers respectively.

An audit document is presented which can be used to assess the radiopharmacy service in a particular institute. It can be used for self-assessment or can form the basis for peer review. The document covers a wide range of aspects of radiopharmacy. It is acknowledged that the document will need constant review and where appropriate, modification, in order to reflect changes in practice or legislation.

A polymer-coated capsule has been used in eight volunteer subjects to deliver 111In-resin into the ileocaecal region. The images were acquired for up to 3 days to follow transit through the colon. Expressing the results of individual studies is difficult and time-activity curves for each region are confusing. Calculation of the geometric centre indicates only where the middle of the activity has reached. We describe a new method of presenting colonic transit data as parametric images. The parametric images show the amount of activity in each area of interest as the study progresses. This is readily understood and allows segmental movement of the isotope, either forward or retrograde, to be examined. The geometric mean of activity in four areas of the colon were also calculated. Four hours after reaching the ileocaecal region, 65% (S.D. 24%) of the activity was in the caecum and 26% (S.D. 20%) in the transverse colon. By 24 h three controls had excreted most of the activity, in two the activity was mainly in the rectum and in two there was still some activity in the transverse colon. A protocol for colonic transit studies, problems with analysis and a new method of presentation of data are discussed.

Analysis of the workload of a nuclear medicine department over the period 1982 to 1986 has shown the prevalence of repeated investigations in individual patients. Records from 23,152 investigations on 17,063 patients indicated that 88.5% received a single administration and only 0.5% received more than four doses of the same radiopharmaceutical. Patterns of usage of a wide range of radiopharmaceuticals are presented and show that the technetium bone imaging agent is the radiopharmaceutical most commonly used for repeated administrations. Analysis of the radiation dose to individual patients arising from radiopharmaceutical administration has shown that only two patients in the survey exceeded 50 mSv per annum and approximately 25% of patients exceeded 5 mSv per annum.

In cultures of Proteus mirabilis the level of R-factor-TEM-mediated β-lactamase activity rose during the logarithmic phase, reached a maximum value at the end of this phase and fell rapidly when the cells entered the stationary phase. Supernatants from cultures in the stationary phase were found to inhibit R-TEM β-lactamase activity both in cell-free preparations and in intact cells. The inhibitory activity may be due to a proteolytic enzyme excreted into the medium.

Summary The application of the 1985 Ionizing Radiations Regulations and Approved Code of Practice to a typical Nuclear Medicine Department has been considered. References to the Regulations are given so that their implications in a given department may be examined. The radiopharmacy, radioisotope dispensary and injection room will need to be Controlled Areas. It will also be necessary to designate Controlled Areas if radiopharmaceuticals are injected in imaging rooms or on wards. Waiting rooms will need to be Controlled Areas. The area around individual patients will, however, not need to be Controlled except for some patients receiving therapeutic doses of 131I for thyrotoxicosis. It should not generally be necessary to designate employees as Classified persons. Major problems in implementing the Regulations are not envisaged in situations where the previous Code of Practice has been followed.

R-plasmid RP1 was transferred to Pseudomonas aeruginosa cells, as indicated by their resistance to carbenicillin, ampicillin, cephaloridine, kanamycin, and tetracycline, and by the presence of a periplasmic beta-lactamase. The wild-type cells (RP1-) were lysed by ethylenediaminetetraacetic acid but not by ethylene-glycol-bis(2-aminoethyl ether)-N,N-tetraacetic acid, whereas cells carrying the plasmid (RP1+) were resistant to both these chelating agents. RP1+ and RP1- strains were both sensitive to the lytic action of polymyxin B and the lethal action of cold shock, but the effect was less marked in the RP1+ cultures. A proportion of the RP1+ cells surviving cold shock lost resistance to carbenicillin, tetracycline, and kanamycin. The chemical composition of whole cells and cell walls of RP1+ differed from that RP1- in the content of cation, phospholipid, and markers for lipopolysaccharide and peptidoglycan. Differences in cell wall composition, response to ethylenediaminetetraacetic acid and polymyxin B, and the effects of cold shock are all compatible with the hypothesis that RP1 confers changes in the cell envelope, probably in the outer membrane, of P. aeruginosa.

The radiation dose to the pulp of both index fingers has been measured in a radiopharmacy supplying 11 000 patient doses a year, in a hospital dispensary (4500 doses a year) and in its injection area. Tungsten syringe shields were used for one week and not used during the other week. In the radiopharmacy and the dispensary the highest finger dose recorded was 6.8 mSv, which corresponds to an annual figure of 330 mSv. Syringe shields gave a protection factor of less than two, and the dose to the left hand was approximately half that to the right. When giving injections the corresponding weekly and annual doses were 4.6 and 220 mSv respectively. If all injections had been given by a single person the corresponding annual dose would have been 430 mSv. Using syringe shields this could be reduced by factors of at least eight for the right hand but only 1.3 for the left hand. Dose rates for unshielded syringes expressed per 10 GBq handled are similar to other data in the literature. However, syringe shields reduce the dose rates less than anticipated. Tungsten 1.94 to 3.05 mm thick would be expected to give an attenuation factor of 27 to 178.

SUMMARY: R-1818 increases swarming and abolishes proteolytic enzyme excretion by P. mirabilis F67. R-TEM reduces swarming, increases proteolytic enzyme excretion by this organism and renders it susceptible to sodium deoxycholate. The properties of strains harbouring both R-1818 and R-TEM simultaneously are dependent on the order of introduction of the R factors, the R factor first present being dominant. Recombination between the R factors in this organism does not seem to be responsible for these observations.

The problem of adverse reactions to radiopharmaceuticals has been reported in this journal by Keeling and Sampson.* I would be grateful if you could publicise the scheme which has been set up in the UK to collate two other types of problem associated with radiopharmaceuticals, namely unusual distribution of the radiopharmaceutical on images and defective products. This scheme is intended to be complementary to the Adverse Reactions reports, such that a more complete picture of radiopharmaceutical problems will emerge.