Lehtinen E, Geiger U
Rontgenblatter. 1978 Feb;31(2):111-3.
A total of 19,577 x-ray films made from 5,092 patients was examined, subdivided into 94 different kinds of examination. The following observations were made: The time since the last x-ray examination of the patient up to Jan. 6 1973 was less than 2 years in 30.1% and less than 5 years in 63.8% of the patients. These figures are due to the fact that the hospital is still very young. The period between two successive x-ray examinations was less than 2 years in 88.2% and less than 5 years in 95.8% of the patients. It is obviously not necessary to file roentgenographs for more than 5 years, since after that time only 4.2% of the patients return for a follow-up examination, and only a fraction of these can probably be regarded as really remarkable (Brolin).
共检查了来自5092名患者的19577张X光片，这些X光片被细分为94种不同类型的检查。得出以下观察结果：截至1973年1月6日，患者上次X光检查后时间不足2年的占30.1%，不足5年的占63.8%。这些数字是由于该医院仍非常新。连续两次X光检查的间隔时间，88.2%的患者不足2年，95.8%的患者不足5年。显然没有必要将X光片存档超过5年，因为此后只有4.2%的患者回来进行后续检查，而且其中可能只有一小部分可被视为真正值得注意的（布罗林）。
