A Spatial Model of Time-Dose-Area Relationships in Radiation Therapy

作者：Carl F. von Essen · 发表于：Radiology · 年份：1963 · 被引用次数：38 · 研究领域：Nonmelanoma Skin Cancer Studies、Advanced Radiotherapy Techniques、Cutaneous Melanoma Detection and Management

Parameters affected by more than two simultaneously changing variables are not easily expressed in nonmathematical terms. This problem was noted in teaching some of the fundamentals of clinical radiation therapy to medical students and resident physicians. In particular, it was difficult to explain the relationships of the cumulative radiation dose, the time of administration of this dose, and the volume or area of exposed normal and malignant tissue to the subsequent biological reactions. In order to give a visual appreciation of these relationships, a three-dimensional model was constructed which has proved to be of benefit in teaching and investigation. Materials and Methods A graph depicting isoeffect curves for skin damage and skin cancer curability has been previously published (1). This graph was modified for demonstration in a three-dimensional form (Fig. 1). From this modification a model was constructed (Fig. 2) with two planes indicating normal tissue and malignant tumor responses respectively. The three axes of the model are dose, time, and area on logarithmic scales. The more steeply inclined plane is the normal-tissue-damage isoeffect plane. All points on this plane have co-ordinates of dose, time, and area that are anticipated to result in a 3 per cent probability of late skin necrosis. The other plane is the tumor-cure isoeffect plane. All points on it have co-ordinates giving a 99 per cent probability of permanent tumor regression. The triangular space betwee...