Clinical aspects of normal tissue complication probability

Abstract

Purpose

To review medical literature data on tolerance doses for a number of radiosensitive organs and put forward some proposals of how to evaluate a treatment plan in terms of the normal tissue complications or how to estimate it in every-day clinical practice.

Material and methods

Studies assessing the relationship between a dose (dose distribution) and radiation injuries of the heart, liver, lung, rectum and parotid gland have been selected for the review.

Results

The Lyman model with Kutcher's reduction algorithm and a relative seriality model proposed by Källman as well as the literature data for the heart, liver, lung, rectum and parotid gland are presented. The parameters of the most often used mathematical models describing the normal tissue complication probability are invoked. The authors’ proposals for simple quantitative parameters to be used in clinical practice are put forward.

Conclusion

Mathematical radiobiological models should be applied with special caution. Up-to-date three dimensional CT treatment planning in radiotherapy makes it possible to collect data for more precise assessment of the relationship between dose and injuries ofsensitive organs.