1 放射生物学.pdfVIP

ESTRO Example:计划如下 Basic Clinical Radiobiology Standard treatment: 35 × 2 Gy = 70 Gy. Correcting dose errors in Initially, schedule given in error as radiation treatment delivery 4 Gy per fraction for first 6 fractions 头 次错给了 次 纠正放疗实施剂量的错误 6 4 Gy/ i.e. first 24 Gy given “hypofractionated” Michael Joiner How to correct? 如何纠正？ Beijing 2007 Consider late injury, use α/β = 3 Gy, Consider tumor effect, use α/β = 10 Gy,肿瘤 考虑晚反应组织 ? 4 + 3? ? 4 +10? EQD2late = 24? ? = 33.6 EQD2tumor = 24? ? = 28 ? 2 + 3? ? 2+10? Therefore, giving rest of treatment as后面为 Therefore, giving rest of treatment as 70 – 33.6 = 36.4 Gy in 2 Gy fractions 70 – 28 = 42 Gy in 2 Gy fractions would give equal late injury as 35 × 2 Gy. would give equal tumor effect as 35 × 2 Gy. 相同晚反应 In practice, 36.4÷2 ≈ 18 (maybe 19) fractions. Therefore: Better solution: 好点的介决 For equal late injury, Initial error was hypofractionated.最初大分割 的total tumor EQD2is ∴ Should be corrected by hyperfractionating 对肿瘤28 + 36.4 = 64.4 Gy to achieve identical tumor effect and late 低了underdosing by 8% injury as expected with 35 × 2 Gy.用超分割 12–20% loss in LTCP?晚反应损伤少了 For equal tumor effect, Solution numerical: total late injury EQD2is