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Published on: March 6, 2018
The Influence of Normal Tissue Objective in the Treatment of Prostate Cancer
Ademar Caldeira1, William Correia Trinca1, Thais Pires Flores1
1Hospital do Cancer, Hospital Mãe de Deus, Porto Alegre, Brazil.
Purpose:
The normal tissue objective (NTO) is a tool used in inverse-planned intensity-modulated radiation therapy to reduce dose spreading to the surrounding tissues. Only a few studies in the present literature are dedicated to understanding the influence of the NTO in radiation therapy planning in patients with prostate cancer or its consequences in the reduction of the dose in the surrounding healthy tissues.
Material And Methods:
Our sample consists of 25 patients submitted to different treatment doses. Averages of plans with and without the NTO were obtained from the dose-volume histogram, and behaviours, comparisons, and quality were assessed considering homogeneity, conformity, and radiation plan indexes.
Results:
We were not able to find significant differences in the conformity index, homogeneity index, and radiation planning index between groups with and without the NTO or between treatment times. We observed a small advantage in NTO plans regarding hot spots in the central region of the planning target volume.
Conclusion:
The NTO is an important tool used in the optimization of plans; however, possibly due to the anatomical location of the prostate, we failed to find a significant contribution of its use in the treatment of prostate cancer. Further studies, using a larger sample and different NTO parameters, are needed to confirm our results.
