Estimate of the genetically significant dose (GSD) in the Mexican population for the years 1996 and 1997

An estimate of the GSD is presented for 1140 radiodiagnostic facilities from a survey carried out by the Ministry of Health in 1996, and 1368 facilities in 1997, corresponding to the 35 and 42% of the total of installations at Mexico respectively. The population in the interviews are divided in three age groups: from 0 to 15, from 16 to 40 and older than 40 years; and 14 different radiological studies are considered, classified by sex. The survey analysis shows that five examinations, that more contribute to the total are: thorax with 29% to 32%, extremities with 19.5% to 19.81%, head and neck with 11.1% to 11.2%, abdomen with 10.0% to 10.7%, and spinal column with 9.2%. The GSD is estimated in a minimum value of 15.4 and a maximum value of 601.9 μGy for the year 1996, and a minimum of 35.0 and a maximum of 1 199.5 μGy for 1997. Values that extrapolated to the total of the establishments correspond from a minimum of 44.0 and a maximum to 1 719.8 μGy for 1996; and 83.3 and 2 855.9 μGy for 1997. For the gonad doses Dg, we took the values of ICRP 34(1982) and UNSCEAR (1972, 1978). The expected number of children is obtained by specific fecundity for each age group in the year of 1996. The analysis of both surveys allows us to determine that: the average is of 923 studies for each thousand individuals, for 100% of the establishments in 1996, and 1 770 studies for each thousand in 1997. The minimum and maximum values of the GSD for Mexicans are 0.16 and 6.2 times in 1996 that the world average value, (that we calculate in 276.5 μGy); and 0.30 and 10.33 times for 1997. We conclude that it is very probable that our values of GSD are underestimated in both cases, because of: I. The estimate values of Dg are smaller to those measured and reported in the literature in other countries. II. It is necessary to optimize the classification of the groups of age of the surveyed people, (more than three groups) and the radiological studies (more than 14 studies) and III. It exist a substantial difference between the number of reported studies: 4 516 876 in 1996, and 10 632 511 in 1997, which is necessary to explain. (author)