Gallium-67 lung uptake: conjugate-view technique

A conjugate-view technique is derived for calculation of absolute gallium-67 (Ga-67) uptake from scintillation-camera images. The technique combines counts of posterior and anterior images of the lung with an attenuation correction obtained from cobalt-57 (Co-57) transmission imaging. The formulation is such that the effects of Compton scatter build-up are accounted for. Studies utilizing a canine model indicated that, normally, more activity is located in the chest wall than in the lungs. The quantitative technique must therefore accurately account for a variety of Ga-67 distributions, including that in the chest wall. Calculations were performed using a three-component model comparing results obtained with the conjugate-view approach to the actual uptake. These calculations suggest that an assumption of uniform activity distribution allows an accuracy of approximately +/- 10% over a broad range of body-part thicknesses and uptake by the lungs. It was concluded that the conjugate-view technique is necessarily approximate but can provide clinically useful results.     

A Study of the mortality of female asbestos workers

Newhouse, M. L., Berry, G., Wagner, J. C., and Turok, M. E. (1972).Brit. J. industr. Med.,29, 134-141. A study of the mortality of female asbestos workers. A cohort study of over 900 women employed at an asbestos factory making both textiles and insulation materials is described. It extends the information about asbestos-related disease at this factory which was previously available only for male workers. The cohort was defined as all the women who started employment at the factory between 1936 and 1942 and the main analysis was of mortality up to the end of 1968. This analysis was made in relation to job, length of exposure, and age at first exposure. Compared with national rates there was excess overall mortality among those who worked in jobs with low to moderate exposure partly accounted for by deaths from cancer. In the group with severe exposure, who had worked in the factory for less than two years, there was an excess of cancer of the lung and pleura. However, the most marked increased mortality was in those with severe exposure who had worked for more than two years in the factory; in this group there were excess deaths from cancer of the lung and pleura, from other cancers, and from respiratory diseases. There were no significant trends of excess mortality with age at first exposure. The smoking habits of some of the deceased women were obtained and the indications were that the proportion of smokers in the cohort was higher than the national rate. This could account for some of the excess mortality but the trend of this excess with exposure indicated the role of asbestos. Necropsy reports and/or histological material were obtained for 43% of those who had died. Three deaths registered as cancer of the pleura were identified as pleural mesothelial tumours; in all there were 11 mesotheliomas, six of pleural and five of peritoneal origin.     

Expanded high iodine dose in computed cranial tomography: a preliminary report.

Fifty patients undergoing cranial CT had expanded-high-iodine-dose (EHID) scans. The EHID was given either as an additional bolus dose (37--40 g iodine) after a routine infusion contrast scan (42.3 g), or as a continuous infusion (total 74--80 g). Diseases presented include primary and metastatic neoplasm, pituitary neoplasm, and demyelinating disease. The results suggest that the primary usefulness of the EHID is in (a) detecting multiple rather than solitary brain lesions, (b) the definitive demonstration of an equivocal area of abnormal enhancement, and (c) differentiating solid histologically microcystic from frankly macrocystic neoplasms.     

A case control study of carcinoma of the ovary.

There is increased concern over the apparent rise in incidence of patients with carcinoma of the ovary, particularly in older women. In an attempt to identify aetiological factors 300 women with cancer of the ovary diagnosed at laparatomy were studied. A questionnaire was administered to these women (Group A) and to two control groups matched by age. The first control group (Group B) comprised patients in a gynaecological ward and the second (Group C) comprised were shown in the obstetric history of the three groups. Fewer of the women in Group A had married and fewer had ever been pregnant and the family size was smaller. Significantly fewer of them recollected an attack of mumps, measles, or rubella. In all, only 81 of the whole series of 900 had used oral contraceptives, 19 of Group A and 31 in each of the control groups, a statistically significant deficiency. These findings support those of other investigations and suggest lines of further inquiry.     

Pneumocystis carinii pneumonia studied by gallium-67 scanning

The validity and reliability of gallium-67 (Ga-67) scanning for diagnosis and follow-up of Pneumocystis carinii pneumonia (PCP) were assessed in 34 patients thought to have pulmonary complications of acquired immunodeficiency syndrome (AIDS). Overall sensitivity was 94% and specificity 74%. Among patients with normal or equivocal chest radiographs at the time of admission, sensitivity was 86% and specificity 85%. The authors consider Ga-67 scanning a valid and reliable adjunct in the diagnosis of PCP in AIDS patients with respiratory symptoms when the chest radiograph is normal or equivocal.