![]() For reasons that become obvious when you look at the back of the watch, it takes the shape of a Chevrolet car grill. (H.H.D.This watch is in terrible shape (a missing hand, missing crystal, worn face), but it has character. ![]() Ingestion of the paint occurred as the result of the workers' habit of pointing their brushes in their mouths before painting the dials. The paint used on the watch dials consisted of crystalline phosphorescent zinc sulfate, rendered luminous by the addition of extremely small amounts of radium and mesothorium or radiothorium. ![]() The patient was unaware that she had received a harmful dose of radioactivity as a more » result of her occupation as a watch dial painter 30 years earlier. Roentgenograms of the long bones, vertebral bodies, and pelvic bones with destruction of both acetabula demonstrated the characteristic pathological changes resulting from irradiation of bone. ![]() Considerable pain and limitation of motion were experienced in spite of medical therapy. The patient had been treated erroneously over a period of years for rheumatoid arthritis involving the shoulder and hip joints. The case history is presented of a 52-year-old female who developed radiation osteitis of multiple bones and an osteogenic sarcoma of the right ilium that proved fatal. The calculated genetic dose for Switzerland is 75 mrem/generation (30 yr), or 2-3% of natural genetic dose. max allowable dose 1.5 rem/ wk), and 0.001 rem/wk at the eye lens (max allowable dose 0.1 rem/ wk). The results were as follows: determination of the nature of radioactive element in watches showed that two contained Sr and all others Ra /sup 226/ amount of radioactivity, as the algebraic mean activity of ordinary watches not containing Sr/sup 90/, was 0.102 mu C of Ra/sup 226/, and the average of watches manafactured in Switzerland in 1960 was 0.092 mu C of Ra/sup 226/ the total dosage was 1 mrem/ hr, that absorbed by the wearer was 0.17 rem/wk at the wrist (cf. Four tests were made on each watch: measurement by a thin-window Geiger-Muller counter of BETA radiation measurement of gamma radiation by means of a NaI-crystal scintillation counter, with a 5% error on highly radioactive watches and more on less active ones measurement of dosage received from the outer back surface of the watch, by a dosimetric film technique, with plus or minus 30% precision classification as legible in the dark or non-legible in the dark, made by more » an observer with watch 20 cm from eyes after 1/2-hr dark adaptation. (tr- auth) « lessĪ study was conducted of 684 Swiss-made watches, approximates 2 of each model, to find the level of radioactivity of their luminous dials. In the cases of watches with maximum activity (more than 2 C Ra) as the doses are cumulative, they can have a harmful effect if the person is exposed at the same time to supplementary irradiation doses (diagnosis and therapy with x rays or radioisotopes). A wrist watch presents no somatic or genetic danger. All these doses are much lower than the permissible dose the gonad doses represent 2 to 7% of the gonad dose of the natural background x radiation. The gonad doses are 6.9 mr/yr for the man's watch of mean activity and 1.5 mr/yr for the woman's watch. The mean dose to the head and eyes is 2.5 r/yr. It was established that the more » mean dose, for carrying the watch 16 hrs a day, was 8 r/yr and, for the watch with the highest activity, 48.3 r/yr. The irradiation doses to different organs caused by the luminous watches were measured on nine persons with film badges. In eight watches the concentration of the radioactive material was more than five times the mean value. The mean concentration of the radioactive material (in 95% of the cases radium salts and mesothorium) was 0.38 C Ra for a man's watch and 0.12 C Ra for a woman's watch. ![]() >The BETA and gamma activities of 156 men's and women's watches of different types and brands were measured using a G-M counter and a Nal crystal scintillator. ![]()
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