| Author: | Chow, Wai Kit |
| Title: | Comparison between in-house self-held respiratory monitoring device and active breathing coordinator system in deep inspiration breath-hold radiotherapy of early-stage left breast cancer |
| 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: | xii, 67 pages : color illustrations |
| Language: | English |
| Abstract: | Purpose/objectives: To find out whether left breast radiotherapy in deep inspiration breath-hold (DIBH) using an in-house self-held respiratory monitoring device (SHRMD) is at least as good as the commercially available Active Breathing Coordinator™ (ABC) system in terms of normal tissue sparing, intrafractional and interfractional position reproducibility, setup accuracy and treatment efficiency. Materials/Methods: Thirty-two early-stage left breast cancer patients who previously received radiotherapy treatment on the left breast or left chest wall only were retrospectively selected. Half of them were treated with SHRMD and the other half by ABC system (n = 16). Forward-planned intensity-modulated radiotherapy (IMRT) plans of DIBH using SHRMD and ABC system were re-generated. Dosimetric comparison was carried out on dosimetric parameters of organs at risk (OARs) including the heart, the left anterior descending coronary artery (LAD) and the left lung between the two DIBH techniques. Daily electronic portal images were acquired in cine loop for measurement of the central lung distance (CLD). The measured CLD in the portal images of all patients were used to compare the intrafractional and interfractional variabilities between using the two DIBH techniques. The differences between the average CLD measured in the portal images and the CLD measured on digitally reconstructed radiographs (DRR) were also evaluated to compare the systematic and random errors between using the two techniques. Finally, the treatment setup time and treatment delivery time were evaluated to compare the treatment efficiency between using the two techniques. Results: No statistically significant difference was found between the two techniques in terms of OAR sparing (all p > 0.05). The intrafractional variabilities of using the SHRMD and the ABC system were 0.55 ± 0.31 mm and 0.23 ± 0.14 mm respectively (p < 0.01), while the interfractional variabilities of using the SHRMD and the ABC system were 2.18 ± 0.60 mm and 1.35 ± 0.37 mm respectively (p < 0.01). DIBH using the SHRMD demonstrated significantly larger intrafractional and interfractional variabilities. Using the SHRMD, the group systematic error M was -0.96 mm, with the standard deviation (SD) of the systematic error Σ and random error σ to be 1.84 mm and 2.25 mm respectively. Using the ABC system, the group systematic error M was -1.01 mm, with the SD of the systematic error Σ and random error σ to be 2.04 mm and 1.39 mm respectively. There were no significant differences in the group systematic error and the SD of the systematic error between the two techniques (all p > 0.05), but the SD of the random error of using the SHRMD was significantly larger (p < 0.01). Treatment setup time and treatment delivery time were similar for both techniques (all p > 0.05). Conclusion: DIBH using the SHRMD could only demonstrate comparable dosimetric outcome and treatment efficiency as using the ABC system. The ABC system was more superior in keeping low intrafractional and interfractional variabilities, and caused smaller random error. Further improvements are required to make the SHRMD become an alternative to the ABC system in all aspects in treating left breast cancer patients. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991022197536803411.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 1.32 MB | Adobe PDF | View/Open |
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