Frequency of Medical X-Ray Examinations in Monroe County, New York

The doses of ionizing radiation received by the population from medical X-ray sources are determined by the numbers and types of examinations performed and by certain dosimetric relationships associated with the techniques employed in each examination type. In Monroe County, N.Y., a survey was undertaken to determine the per capita rates with which the various medical radiological examinations were performed in a large, predominantly urban population with a high level of medical care. Age, sex, and type-specific rates are given for 20 categories of diagnostic examinations. Rates in general increased with age, but the patterns of increase varied considerably by age, sex, and type of examination. Many skeletal and other examinations varied seasonally, in some cases apparently as the result of variations in weather and in athletic activities. In a subsample of those examined, the percentage of women pregnant was similar to that estimated for the general population. Also, the 3-year survival rates of examinees less than 35 years of age were essentially the same as those of the general population. In addition to the use of X-ray examination rates in assessing population doses of ionizing radiation, the study of such rates is useful to epidemiologists in a variety of ways.