| Author: | Mok, To Wing |
| Title: | Dosimetric comparsion of routine rapidarc and split field rapidarc for left breast cancer patients with different breast size |
| Advisors: | Wu, Vincent (HTI) |
| Degree: | M.Sc. |
| Year: | 2019 |
| Subject: | Hong Kong Polytechnic University -- Dissertations Breast -- Cancer -- Radiotherapy |
| Department: | Department of Health Technology and Informatics |
| Pages: | viii, 46 pages : color illustrations |
| Language: | English |
| Abstract: | Purpose/objectives: To compare the dosimetric difference between Routine Rapidarc (R-RA) and Split field Rapidarc (SF-RA) techniques and to investigate the effects of breast size on the two techniques. Materials/Methods: Thirty-six patients with left-sided breast cancer with negative lymph nodes after lumpectomy were recruited in this study. Two Rapidarc techniques, R-RA and SF-RA, were planned using the planning CT image set of the patients. The patients were divided into large breast and small breast groups by the median of CTVbreast. Dosimetric comparison between R-RA and SF-RA of the left-sided breast cancer was carried out between the two groups. The statistical analyses were performed using SPSS to test the differences between the dose parameters of target and OARs resulted from R-RA and SF-RA within groups of small and large breast. Linear regression was also carried to investigate effects of breast size on the two techniques. Results: The CTV volume of the subjects collected ranged from 150cm3 to 1050cm3. The median volume of the CTV (393cm3) was used to classify the subgroups, small and large breast, for the study. In both small and large breast groups, the dose distribution in PTV breast eval of SF-RA was superior to that of R-RA. SF-RA could significantly improve D98%, V107% and HI in both small and large breast groups when compared to R-RA. For OARs, SF-RA significantly reduced the doses to ipsilateral lung, heart, oesophagus and spinal cord compared to R-RA. The drawbacks of SF-RA were increased the doses to right lung, MUs and treatment time. The study result showed that breast size had no linear relationships with dosimertic outcomes except CI. The R value of CI was 0.77 for R-RA and 0.71 for SF-RA (p<0.05). The smaller the breast size was, the worse the conformity of the target would be generated by R-RA and SF-RA. Conclusion: SF-RA provided better dose homogeneity of the target and more effective in OARs sparing in small and large breast groups compared to R-RA. SF-RA is suggested applying to general practice if the slight increased treatment time can be afforded. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991022197536603411.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 976.78 kB | Adobe PDF | View/Open |
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