Accumulated dose in external radiation for cervical cancer based on three registration methods
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《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2018年第2期
- Page:
- 151-155
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Accumulated dose in external radiation for cervical cancer based on three registration methods
- Author(s):
- LIANG Youteng; YU Hui; ZHANG Shuxu
- Radiotherapy Center, Cancer Center of Guangzhou Medical University, Guangzhou 510095, China
- Keywords:
- ; Keywords: cervical cancer; deformable image registration; external radiation; accumulated dose
- PACS:
- R730.55
- DOI:
- DOI:10.3969/j.issn.1005-202X.2018.02.006
- Abstract:
- Objective To discuss the accumulated dose in external radiation for cervical cancer with three registration methods, namely B-spline nonrigid registration, affine registration and rigid registration, and compare the differences in accumulated doses. Methods The fractional therapy computed tomography (CT) images of ten cervical cancer patients receiving localizations of radiotherapy twice between January 2015 and February 2016 were analyzed. The second therapy CT images (I2) which were regarded as the reference were registered with the first therapy CT images (I1) by B-spline nonrigid registration, affine registration and rigid registration, respectively. The normalized mutual information (MI) and mean absolute deviation (MAD) were used to evaluate the registration accuracies of different registration methods. And then, the intensity-modulated radiotherapy dose of I1 was accumulated to I2, obtaining the accumulated dose of three registration methods (DB, DF and DG, respectively). Finally, the differences between DF and DB, DG and DB were compared. Results For the registration accuracy, the MI values of three registration methods were 1.27±0.02, 1.24±0.03 and 1.24±0.02, respectively. The larger the MI value was, the higher the accuracy became. The MAD values of three registration methods were 4.93±1.03, 6.36±1.59 and 6.76±1.77, respectively. The smaller the MAD value was, the higher the accuracy became. For the differences of accumulated dose, the MAD between DF and DB, DG and DB was 64.8±49.7 and 72.9±47.5, respectively. Though the deviations between DF and DB, DG and DB reached maximum in the V50 of the rectum and the bladder, no statistical differences were found in dose-volume histogram parameters (the D50% and V50 of the rectum and the bladder, the D95% and Dmean of clinical target volume and gross tumor volume). Conclusion Three-dimensional elastic registration was recommended in the registration for the fractional therapy CT images obtained in external radiation for cervical cancer for it can achieve high registration accuracy and obtain more accurate accumulated doses.
Last Update: 2018-01-29