Objective To investigate the dosimetric influence of dwell weight standard deviation (DWSD) and applicator displacement in cervical cancer patients treated with three-dimensional brachytherapy. Methods A total of 20 cervical cancer patients who had completed radical treatment were selected in this study. The Fletcher applicator (Nucletron#189.730) was used for these patients. A new plan, based on the former CT images and structures, was designed for each patient. In former and new plans, dwell weight was recorded, and DWSD was calculated. Two groups, low-DWSD (LDWSD, 0.141-0.299) and high-DWSD (HDWSD, 0.211-0.337), were set according to the DWSD size for the two plans. Dosimetric effects from ±1 mm displacement of tandem applicator or ovoid applicator were simulated with Oncentra? Brachy V4.3 treatment planning system. D100, D90, and V150 for clinical target volume (CTV) and D0.1cc, D1cc, and D2cc for the bladder, rectum, and sigmoid were evaluated. Dosimetric comparisons were made between the LDWSD group and HDWSD group to study the dosimetric effects of DWSD and applicator displacement in cervical cancer patients. Results The dosimetric effects from applicator displacement increased with increasing DWSD. If there was a 1 mm displacement of tandem applicator or ovoid applicator, D100, D90, and V150 of CTV were 3.0%, 23.8%, and 4.8% higher or 0.5%, 1.2%, and 5.2% higher in the HDWSD group than in the LDWSD group;D0.1cc, D1cc, and D2cc of the bladder and rectum were significantly higher in the HDWSD group than in the LDWSD group, particularly for the sigmoid (up 44.0%, 22.8%, and 16.8%) and (up 10.3%, 14.4%, and 12.4%). Conclusions DWSD should be considered in plan evaluation for cervical cancer patients treated with three-dimensional brachytherapy. The dosimetric influence from applicator displacement can be decreased by reducing DWSD properly.
National Major Scientific Instruments and Equipment Development (2013YQ090811)
Corresponding Authors:
Wang Pei,Email:dengwangpei@163.com
Cite this article:
Wang Xianliang,Wu Junxiang,Yuan Ke et al. Dosimetric influence of dwell weight standard deviation and applicator displacement in patients with cervical cancer[J]. Chinese Journal of Radiation Oncology, 2017, 26(4): 419-422.
Wang Xianliang,Wu Junxiang,Yuan Ke et al. Dosimetric influence of dwell weight standard deviation and applicator displacement in patients with cervical cancer[J]. Chinese Journal of Radiation Oncology, 2017, 26(4): 419-422.
[1] Kirisits C,Rivard MJ,Baltas D,et al. Review of clinical brachytherapy uncertainties:analysis guidelines of GEC-ESTRO and the AAPM[J].Radiother Oncol,2014,110(1):199-212.DOI:10.1016/j.radonc.2013.11.002
[2] De Leeuw AAC,Moerland MA,Nomden C,et al. Applicator reconstruction and applicator shifts in 3D MR-based PDR brachytherapy of cervical cancer[J].Radiother Oncol,2009,93(2):341-346.DOI:10.1016/j.radonc.2009.05.003
[3] Shi D,He MY,Zhao ZP,et al. Utrecht interstitial applicator shifts and DVH parameter changes in 3D CT-based HDR brachytherapy of cervical cancer[J].Asian Pac J Cancer Prev,2015,16(9):3945-3949.DOI:10.7314/APJCP.2015.16.9.3945
[4] Smith RL,Panettieri V,Lancaster C,et al. The influence of the dwell time deviation constraint (DTDC) parameter on dosimetry with IPSA optimisation for HDR prostate brachytherapy[J].Australas Phys Eng Sci Med,2015,38(1):55-61.DOI:10.1007/s13246-014-0317-2
[5] Chajon E,Dumas I,Touleimat M,et al. Inverse planning approach for 3-D MRI-based pulse-dose rate intracavitary brachytherapy in cervix cancer[J].Int J Radiat Oncol Biol Phys,2007,69(3):955-961.DOI:10.1016/j.ijrobp.2007.07. 2321
[6] Haie-Meder C,P?tter R,Van Limbergen E,et al. Recommendations from Gynaecological (GYN) GEC-ESTRO Working Group☆(I):concepts and terms in 3D image based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV[J].Radiother Oncol,2005,74(3):235-245.DOI:10.1016/j.radonc.2004.12.015
[7] A European study on MRI-guided brachytherapy in locally advanced cervical cancer[DB/OL][2016-08-25].https://www.embracestudy.dk/
[8] Hellebust TP,Kirisits C,Berger D,et al. Recommendations from Gynaecological (GYN) GEC-ESTRO Working Group:considerations and pitfalls in commissioning and applicator reconstruction in 3D image-based treatment planning of cervix cancer brachytherapy[J].Radiother Oncol,2010,96(2):153-160.DOI:10.1016/j.radonc.2010.06.004
[9] Jamema SV,Sharma S,Mahantshetty U,et al. Comparison of IPSA with dose-point optimization and manual optimization for interstitial template brachytherapy for gynecologic cancers[J].Brachytherapy,2011,10(4):306-312.DOI:10.1016/j.brachy.2010.08.011.
[10] P?tter R,Haie-Meder C,Limbergen EV,et al. Recommendations from gynaecological (GYN) GEC ESTRO working group (Ⅱ):concepts and terms in 3D image-based treatment planning in cervix cancer brachytherapy-3D dose volume parameters and aspects of 3D image-based anatomy,radiation physics,radiobiology[J].Radiother Oncol,2006,78(1):67-77.DOI:10.1016/j.radonc.2005.11.014.
[11] 彭倩,王培,王先良,等.宫颈癌内外照射中基于CBCT外照射摆位误差分析[J].中华放射肿瘤学杂志,2016,25(10):1113-1116.DOI:10.3760/cma.j.issn.1004-4221.2016.10.020.
Peng Q,Wang P,Wang XL,et al. Setup errors of external-beam and intracavitary radiotherapy for cervical cancer:an analysis based on cone-beam computed tomography[J].Chin J Radiat Oncol,2016,25(10):1113-1116.DOI:10.3760/cma.j.issn.1004-4221.2016.10.020.
[12] Schindel J,Zhang W,Bhatia SK,et al. Dosimetric impacts of applicator displacements and applicator reconstruction- uncertainties on 3D image-guided brachytherapy for cervical cancer[J].J Contemp Brachytherapy,2013,5(4):250-257.DOI:10.5114/ jcb.2013.39453.
[13] Poulin E,Varfalvy N,Aubin S,et al. Comparison of dose and catheter optimization algorithms in prostate high-dose-rate brachytherapy[J].Brachytherapy,2016,15(1):102-111.DOI:10.1016/j.brachy.2015.09.010.
[14] Trnková P,Baltas D,Karabis A,et al. A detailed dosimetric comparison between manual and inverse plans in HDR intracavitary/interstitial cervical cancer brachytherapy[J].J Contemp Brachytherapy,2010,2(4):163-170.DOI:10.5114/jcb.2010.19497.
[15] Trnková P,P?tter R,Baltas D,et al. New inverse planning technology for image-guided cervical cancer brachytherapy:description and evaluation within a clinical frame[J].Radiother Oncol,2009,93(2):331-340.DOI:10.1016/j.radonc.2009.10.004.
2017, Vol. 26 
