An evaluation of gastric mass survey from the standpoint of expectation of life

The authors reexamined the evaluation of mass gastric survey, which had previously been reported by them, from the standpoint of expectation of life and advocated new theories, the number of years of expected lifesaving and the rate of loss and gain of years. Comparison between the new evaluation and the pre-existing evaluation produces the following differences. (1) The number of years of expected lifesaving increases rapidly from the 50s to reach a peak in the 60s and to decrease from the 70s. This is more realistic and reasonable than the pre-existing method by which the higher the age, the more is gain increased. (2) The rate of loss and gain of mass gastric survey increases in each age group. In other words, the value of mass gastric survey is evaluated more highly. While the importance of mass gastric survey has recently been recognized, the number of examinees increasing, injury due to exposure to radiation has become a serious problem. Therefore, it was thought to be important to perform mass gastric survey efficiently on subjects limited based on the theory investigated from both aspects of advantage and disadvantage. (Chiba, N.)