A novel curvilinear approach for prostate seed implantation.

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Title:	A novel curvilinear approach for prostate seed implantation.
Authors:	Podder, Tarun K.¹, Dicker, Adam P.², Hutapea, Parsaoran³, Darvish, Kurosh³, Yu, Yan²
Source:	Medical Physics. Apr2012, Vol. 39 Issue 4, p1887-1892. 6p.
Subjects:	Dosimeters, Radioisotope brachytherapy, Radiation doses, Prostate cancer, Rectal radiography, Parameter estimation, Health outcome assessment
Abstract:	Purpose: A new technique called 'curvilinear approach' for prostate seed implantation has been proposed. The purpose of this study is to evaluate the dosimetric benefit of curvilinear distribution of seeds for low-dose-rate (LDR) prostate brachytherapy. Methods: Twenty LDR prostate brachytherapy cases planned intraoperatively with VariSeed planning system and I-125 seeds were randomly selected as reference rectilinear cases. All the cases were replanned by using curved-needle approach keeping the same individual source strength and the volume receiving 100% of prescribed dose 145 Gy (V100). Parameters such as number of needles, seeds, and the dose coverage of the prostate (D90, V150, V200), urethra (D30, D10) and rectum (D5, V100) were compared for the rectilinear and the curvilinear methods. Statistical significance was assessed using two-tailed student's t-test. Results: Reduction of the required number of needles and seeds in curvilinear method were 30.5% (p < 0.001) and 11.8% (p < 0.49), respectively. Dose to the urethra was reduced significantly; D30 reduced by 10.1% (p < 0.01) and D10 reduced by 9.9% (p < 0.02). Reduction in rectum dose D5 was 18.5% (p < 0.03) and V100 was also reduced from 0.93 cc in rectilinear to 0.21 cc in curvilinear (p < 0.001). Also the V150 and V200 coverage of prostate reduced by 18.8% (p < 0.01) and 33.9% (p < 0.001), respectively. Conclusions: Significant improvement in the relevant dosimetric parameters was observed in curvilinear needle approach. Prostate dose homogeneity (V150, V200) improved while urethral dose was reduced, which might potentially result in better treatment outcome. Reduction in rectal dose could potentially reduce rectal toxicity and complications. Reduction in number of needles would minimize edema and thereby could improve postimplant urinary incontinence. This study indicates that the curvilinear implantation approach is dosimetrically superior to conventional rectilinear implantation technique. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	Purpose: A new technique called 'curvilinear approach' for prostate seed implantation has been proposed. The purpose of this study is to evaluate the dosimetric benefit of curvilinear distribution of seeds for low-dose-rate (LDR) prostate brachytherapy. Methods: Twenty LDR prostate brachytherapy cases planned intraoperatively with VariSeed planning system and I-125 seeds were randomly selected as reference rectilinear cases. All the cases were replanned by using curved-needle approach keeping the same individual source strength and the volume receiving 100% of prescribed dose 145 Gy (V100). Parameters such as number of needles, seeds, and the dose coverage of the prostate (D90, V150, V200), urethra (D30, D10) and rectum (D5, V100) were compared for the rectilinear and the curvilinear methods. Statistical significance was assessed using two-tailed student's t-test. Results: Reduction of the required number of needles and seeds in curvilinear method were 30.5% (p < 0.001) and 11.8% (p < 0.49), respectively. Dose to the urethra was reduced significantly; D30 reduced by 10.1% (p < 0.01) and D10 reduced by 9.9% (p < 0.02). Reduction in rectum dose D5 was 18.5% (p < 0.03) and V100 was also reduced from 0.93 cc in rectilinear to 0.21 cc in curvilinear (p < 0.001). Also the V150 and V200 coverage of prostate reduced by 18.8% (p < 0.01) and 33.9% (p < 0.001), respectively. Conclusions: Significant improvement in the relevant dosimetric parameters was observed in curvilinear needle approach. Prostate dose homogeneity (V150, V200) improved while urethral dose was reduced, which might potentially result in better treatment outcome. Reduction in rectal dose could potentially reduce rectal toxicity and complications. Reduction in number of needles would minimize edema and thereby could improve postimplant urinary incontinence. This study indicates that the curvilinear implantation approach is dosimetrically superior to conventional rectilinear implantation technique. [ABSTRACT FROM AUTHOR]
ISSN:	00942405
DOI:	10.1118/1.3694110