Journal of Medical Physics
ORIGINAL ARTICLE
Year
: 2020  |  Volume : 45  |  Issue : 2  |  Page : 78--87

Evaluation of dose distribution and normal tissue complication probability of a combined dose of cone-beam computed tomography imaging with treatment in prostate intensity-modulated radiation therapy


Tetsuya Tomita1, Tomonori Isobe2, Yoshinobu Furuyama3, Hideyuki Takei2, Daisuke Kobayashi1, Yutaro Mori2, Toshiyuki Terunuma2, Eisuke Sato4, Hiroshi Yokota6, Takeji Sakae2 
1 Graduate School of Comprehensive Human Sciences, University of Tsukuba; Department of Radiology, University of Tsukuba Hospital, Ibaraki, Japan
2 Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
3 Department of Radiology, Chiba University Hospital, Chiba, Japan
4 Faculty of Health Sciences, Juntendo University, Tokyo, Japan

Correspondence Address:
Prof. Tomonori Isobe
1-1-1 Tennodai, Tsukuba, Ibaraki
Japan

Purpose: The purpose of this study is to evaluate the effects of cone-beam computed tomography (CBCT) on dose distribution and normal tissue complication probability (NTCP) by constructing a comprehensive dose evaluation system for prostate intensity-modulated radiation therapy (IMRT). Methods: A system that could combine CBCT and treatment doses with MATLAB was constructed. Twenty patients treated with prostate IMRT were studied. A mean dose of 78 Gy was prescribed to the prostate region, excluding the rectal volume from the target volume, with margins of 4 mm to the dorsal side of the prostate and 7 mm to the entire circumference. CBCT and treatment doses were combined, and the dose distribution and the NTCP of the rectum and bladder were evaluated. Results: The radiation dose delivered to 2% and 98% of the target volume increased by 0.90 and 0.74 Gy on average, respectively, in the half-fan mode and on average 0.76 and 0.72 Gy, respectively, in the full-fan mode. The homogeneity index remained constant. The percent volume of the rectum and bladder irradiated at each dose increased slightly, with a maximum increase of <1%. The rectal NTCP increased by approximately 0.07% from 0.46% to 0.53% with the addition of a CBCT dose, while the maximum NTCP in the bladder was approximately 0.02%. Conclusions: This study demonstrated a method to evaluate a combined dose of CBCT and a treatment dose using the constructed system. The combined dose distribution revealed increases of <1% volume in the rectal and bladder doses and approximately 0.07% in the rectal NTCP.


How to cite this article:
Tomita T, Isobe T, Furuyama Y, Takei H, Kobayashi D, Mori Y, Terunuma T, Sato E, Yokota H, Sakae T. Evaluation of dose distribution and normal tissue complication probability of a combined dose of cone-beam computed tomography imaging with treatment in prostate intensity-modulated radiation therapy.J Med Phys 2020;45:78-87


How to cite this URL:
Tomita T, Isobe T, Furuyama Y, Takei H, Kobayashi D, Mori Y, Terunuma T, Sato E, Yokota H, Sakae T. Evaluation of dose distribution and normal tissue complication probability of a combined dose of cone-beam computed tomography imaging with treatment in prostate intensity-modulated radiation therapy. J Med Phys [serial online] 2020 [cited 2020 Dec 5 ];45:78-87
Available from: https://www.jmp.org.in/article.asp?issn=0971-6203;year=2020;volume=45;issue=2;spage=78;epage=87;aulast=Tomita;type=0