Chromosome dosimetry and occupational radiation exposure.

Chromosome analyses were carried out on lymphocytes from 11 persons with annual exposures to gamma rays below the occupational limit of 50 mSv, employed in a hospital department of radiotherapy and nuclear medicine. Cytogenetic damage indicated radiation exposure significantly above background in six cases. In four of them a dose estimate between 30 and 275 mSv with 95% confidence was derived, reflecting their accumulated occupational exposures. In one case a partial body exposure to about 30% of lymphocytes was inferred and inquiries revealed previously unknown radiotherapy. In order to avoid misinterpretation of cytogenetic data, reliable chromosome dosimetry requires that the individual's radiation history must be known

Experimental determination of conversion factors between organ doses and measured quantities for external photon irradiation.

For external photon radiation, conversion factors between organ doses and the quantities normally measured in radiation protection were determined experimentally using an anthropomorphic phantom and thermoluminescent dosimeters. The measurements were made for different energies and irradiation geometries. As normalization quantities, the exposure measured in free air and the dose equivalent in soft tissue measured at a personal dosimeter site were used. The results are compared with conversion factors calculated by other authors

On the Influence of the Exposure Model on Organ Doses.

For the determination of organ doses and the effective dose equivalent either physical or mathematical exposure models have to be used in order to establish suitable conversion factors between the dose values considered and certain measurable quantities. As the measurement of dose distributions in a realistic phantom of the human body is restricted to special situations, most of the conversion factors needed have to be derived by theoretical calculations using mathematical human phantoms and, usually, Monte Carlo methods. For these calculations, various more or less simplified models of the radiation source, the human body and the interactions between radiation and matter have been introduced. In this work, some examples of the influence of details in modelling on the resulting organ doses are demonstrated

Ermittlung der effektiven äquivalentdosis bei der Gynakologischen Radiumtherapie.

In this study, the authors describe how to determine the effective dose-equivalent absorbed by occupationally-exposed persons during a gynecologic radium therapy. The observed irradiation conditions of the physician and the medical staff are approximated by a standard geometry, for which conversion factors between the measured personal dose, the effective-dose equivalent and different organ doses, respectively, are calculated. The results are job-specific conversion factors between the dose dose according to a personal dosimeter and the effective dose-equivalent for the occupational-exposed persons involved. According to the individual tasks, these factors are between 0.59 and 1.13