BACKGROUND AND PURPOSE: The aim was to evaluate the impact of a spacer gel on the dose distribution, applying three-dimensional conformal (3D CRT) and intensity modulated radiotherapy (IMRT) planning techniques. MATERIAL AND METHODS: The injection of a spacer gel (10 ml SpaceOAR™) was performed between the prostate and rectum under transrectal ultrasound guidance in 18 patients with prostate cancer. 3D CRT and IMRT treatment plans were compared based on CT before and after injection (78 Gy prescription dose). RESULTS: In contrast to the PTV and bladder, significant advantages (p<0.01) resulted in respect of all analysed rectal dose values comparing pre spacer with post spacer plans for both techniques. Rectal NTCP (normal tissue complication probability) reached the lowest percentage after spacer injection irrespective of the technique, with a mean reduction of >50% for both IMRT and 3D CRT. Significantly (p<0.01) higher D(mean), and V(78) for the PTV were reached with IMRT vs. 3D CRT plans, with a smaller rectum V(76) but larger rectum V(50). CONCLUSIONS: The injection of a spacer gel between the prostate and anterior rectal wall is associated with considerably lower doses to the rectum and consequentially lower NTCP values irrespective of the radiotherapy technique.
BACKGROUND AND PURPOSE: The aim was to evaluate the impact of a spacer gel on the dose distribution, applying three-dimensional conformal (3D CRT) and intensity modulated radiotherapy (IMRT) planning techniques. MATERIAL AND METHODS: The injection of a spacer gel (10 ml SpaceOAR™) was performed between the prostate and rectum under transrectal ultrasound guidance in 18 patients with prostate cancer. 3D CRT and IMRT treatment plans were compared based on CT before and after injection (78 Gy prescription dose). RESULTS: In contrast to the PTV and bladder, significant advantages (p<0.01) resulted in respect of all analysed rectal dose values comparing pre spacer with post spacer plans for both techniques. Rectal NTCP (normal tissue complication probability) reached the lowest percentage after spacer injection irrespective of the technique, with a mean reduction of >50% for both IMRT and 3D CRT. Significantly (p<0.01) higher D(mean), and V(78) for the PTV were reached with IMRT vs. 3D CRT plans, with a smaller rectum V(76) but larger rectum V(50). CONCLUSIONS: The injection of a spacer gel between the prostate and anterior rectal wall is associated with considerably lower doses to the rectum and consequentially lower NTCP values irrespective of the radiotherapy technique.
Authors: Nicholas G Zaorsky; Amy S Harrison; Edouard J Trabulsi; Leonard G Gomella; Timothy N Showalter; Mark D Hurwitz; Adam P Dicker; Robert B Den Journal: Nat Rev Urol Date: 2013-09-10 Impact factor: 14.432
Authors: M E Schutzer; P F Orio; M C Biagioli; D A Asher; H Lomas; D Moghanaki Journal: Prostate Cancer Prostatic Dis Date: 2015-02-17 Impact factor: 5.554
Authors: Raymond B King; Sarah Os Osman; Ciaran Fairmichael; Denise M Irvine; Ciara A Lyons; Ananth Ravi; Joe M O'Sullivan; Alan R Hounsell; Darren M Mitchell; Conor K McGarry; Suneil Jain Journal: Br J Radiol Date: 2018-01-23 Impact factor: 3.039