Vaudaux Catherine, Schneider Uwe, Kaser-Hotz Barbara
Section of Diagnostic Imaging and Radio-Oncology, Vetsuisse-Faculty University of Zürich, Winterthurerstrasse 260, 8057 Zürich, Switzerland.
Vet Radiol Ultrasound. 2007 Sep-Oct;48(5):475-81. doi: 10.1111/j.1740-8261.2007.00282.x.
We evaluated the impact of inverse planned intensity-modulated radiation therapy (IMRT) on the dose-volume histograms (DVHs) and on the normal tissue complication probabilities (NTCPs) of brain and eyes in dogs with nasal tumors. Nine dogs with large, caudally located nasal tumors were planned using conventional techniques and inverse planned IMRT for a total prescribed dose of 52.5 Gy in 3.5 Gy fractions. The equivalent uniform dose for brain and eyes was calculated to estimate the normal tissue complication probability (NTCP) of these organs. The NTCP values as well as the DVHs were used to compare the treatment plans. The dose distribution in IMRT plans was more conformal than in conventional plans. The average dose delivered to one-third of the brain was 10 Gy lower with the IMRT plan compared with conventional planning. The mean partial brain volume receiving 43.6 Gy or more was reduced by 25.6% with IMRT. As a consequence, the NTCPs were also significantly lower in the IMRT plans. The mean NTCP of brain was two times lower and at least one eye could be saved in all patients planed with IMRT. Another possibility with IMRT is dose escalation in the target to improve tumor control while keeping the NTCPs at the same level as for conventional planning. Veterinary
我们评估了逆向计划调强放射治疗（IMRT）对患有鼻腔肿瘤犬只的剂量体积直方图（DVH）以及脑和眼的正常组织并发症概率（NTCP）的影响。对9只患有大型、位于尾部的鼻腔肿瘤的犬只，分别采用传统技术和逆向计划IMRT进行计划，总处方剂量为52.5 Gy，分3.5 Gy分次给予。计算脑和眼的等效均匀剂量，以估计这些器官的正常组织并发症概率（NTCP）。NTCP值以及DVH用于比较治疗计划。IMRT计划中的剂量分布比传统计划更适形。与传统计划相比，IMRT计划使输送至三分之一脑体积的平均剂量降低了10 Gy。接受43.6 Gy或更高剂量的平均部分脑体积在IMRT时减少了25.6%。因此，IMRT计划中的NTCP也显著更低。脑的平均NTCP降低了两倍，并且在所有接受IMRT计划的患者中至少可以挽救一只眼睛。IMRT的另一种可能性是在靶区增加剂量以改善肿瘤控制，同时使NTCP保持在与传统计划相同的水平。兽医
