Application Of MRI Simulation In Precise Radiotherapy For Prostate Cancer

Objective: As one of the important treatment methods for prostate cancer,radiotherapy plays an irreplaceable role in improving the survival rate of prostate cancer patients,prolonging the survival time,and alleviating the pain of late patients.This paper aims to study the application of magnetic resonance imaging and location technology in prostate cancer target area and endangered organ delineation,and explore its impact on target area and organ volume and dose.Methods: From September 2016 to March 2018 in our hospital,15 patients undergoing radiotherapy for prostate cancer underwent conventional CT simulation and magnetic resonance imaging in the same position.CT positioning was used to diagnose magnetic resonance images and locate magnetic resonance images respectively.The fusion was performed to delineate prostate,seminal vesicle target,rectum and bladder endangered organs,and a three-dimensional conformal intensity enhancement plan was designed on the basis to compare the difference in dose volume histogram parameters between the target area and the endangered organ.Results: The mean volumes of the prostate gland and seminal vesicle glands mapped by CT-based localization fusion diagnostic magnetic resonance imaging and magnetic resonance imaging were 109.05 and 101.25 cm3(t=1.55,P=0.151),respectively.Rectal V30 and V50 were performed after IMRT planning.,V70 were 96.78%,93.71%(t=2.65,P=0.019);54.15%,48.51%(t=3.61,P=0.003);16.02,12.66(t=7.109,P=0.000),mean bladder dose 48.02 Gy and 48.14 Gy,respectively(t=-0.05,P=0.959),while the latter target zone has better conformity index(0.72 VS 0.77 t=-2.79,P=0.019).Conclusion: There is no statistical difference between the volume of the prostate gland and seminal vesicles drawn on the basis of magnetic resonance simulation and location mapping and conventional fusion magnetic resonance images.However,based on magnetic resonance location images,the intensity of radiotherapy plan is drawn to define the target area rather than magnetic fusion based on CT fusion.The resonance image can significantly reduce the rectal volume irradiated by higher doses,and the target area has better conformability.Therefore,the clinical application of MRI-based localization technology in accurate radiotherapy of prostate cancer deserves further promotion.