Development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapy
Adaptive radiotherapy may improve treatment outcomes for lung cancer patients. Because of the lack of an effective tool for quality assurance, this therapeutic modality is not yet accepted in clinic. The purpose of this study is to develop a deformable physical phantom for validation of dose accumul...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wolters Kluwer Medknow Publications
2016-01-01
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| Series: | Journal of Medical Physics |
| Subjects: | |
| Online Access: | http://www.jmp.org.in/article.asp?issn=0971-6203;year=2016;volume=41;issue=2;spage=106;epage=114;aulast=Zhong |
| _version_ | 1819081409657044992 |
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| author | Hualiang Zhong Jeffrey Adams Carri Glide-Hurst Hualin Zhang Haisen Li Indrin J Chetty |
| author_facet | Hualiang Zhong Jeffrey Adams Carri Glide-Hurst Hualin Zhang Haisen Li Indrin J Chetty |
| author_sort | Hualiang Zhong |
| collection | DOAJ |
| description | Adaptive radiotherapy may improve treatment outcomes for lung cancer patients. Because of the lack of an effective tool for quality assurance, this therapeutic modality is not yet accepted in clinic. The purpose of this study is to develop a deformable physical phantom for validation of dose accumulation algorithms in regions with heterogeneous mass. A three-dimensional (3D) deformable phantom was developed containing a tissue-equivalent tumor and heterogeneous sponge inserts. Thermoluminescent dosimeters (TLDs) were placed at multiple locations in the phantom each time before dose measurement. Doses were measured with the phantom in both the static and deformed cases. The deformation of the phantom was actuated by a motor driven piston. 4D computed tomography images were acquired to calculate 3D doses at each phase using Pinnacle and EGSnrc/DOSXYZnrc. These images were registered using two registration software packages: VelocityAI and Elastix. With the resultant displacement vector fields (DVFs), the calculated 3D doses were accumulated using a mass-and energy congruent mapping method and compared to those measured by the TLDs at four typical locations. In the static case, TLD measurements agreed with all the algorithms by 1.8% at the center of the tumor volume and by 4.0% in the penumbra. In the deformable case, the phantom's deformation was reproduced within 1.1 mm. For the 3D dose calculated by Pinnacle, the total dose accumulated with the Elastix DVF agreed well to the TLD measurements with their differences <2.5% at four measured locations. When the VelocityAI DVF was used, their difference increased up to 11.8%. For the 3D dose calculated by EGSnrc/DOSXYZnrc, the total doses accumulated with the two DVFs were within 5.7% of the TLD measurements which are slightly over the rate of 5% for clinical acceptance. The detector-embedded deformable phantom allows radiation dose to be measured in a dynamic environment, similar to deforming lung tissues, supporting the validation of dose mapping and accumulation operations in regions with heterogeneous mass, and dose distributions. |
| first_indexed | 2024-12-21T20:00:19Z |
| format | Article |
| id | doaj.art-8512138b3eb949a8b36caae71b1739ba |
| institution | Directory Open Access Journal |
| issn | 0971-6203 1998-3913 |
| language | English |
| last_indexed | 2024-12-21T20:00:19Z |
| publishDate | 2016-01-01 |
| publisher | Wolters Kluwer Medknow Publications |
| record_format | Article |
| series | Journal of Medical Physics |
| spelling | doaj.art-8512138b3eb949a8b36caae71b1739ba2022-12-21T18:51:59ZengWolters Kluwer Medknow PublicationsJournal of Medical Physics0971-62031998-39132016-01-0141210611410.4103/0971-6203.181641Development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapyHualiang ZhongJeffrey AdamsCarri Glide-HurstHualin ZhangHaisen LiIndrin J ChettyAdaptive radiotherapy may improve treatment outcomes for lung cancer patients. Because of the lack of an effective tool for quality assurance, this therapeutic modality is not yet accepted in clinic. The purpose of this study is to develop a deformable physical phantom for validation of dose accumulation algorithms in regions with heterogeneous mass. A three-dimensional (3D) deformable phantom was developed containing a tissue-equivalent tumor and heterogeneous sponge inserts. Thermoluminescent dosimeters (TLDs) were placed at multiple locations in the phantom each time before dose measurement. Doses were measured with the phantom in both the static and deformed cases. The deformation of the phantom was actuated by a motor driven piston. 4D computed tomography images were acquired to calculate 3D doses at each phase using Pinnacle and EGSnrc/DOSXYZnrc. These images were registered using two registration software packages: VelocityAI and Elastix. With the resultant displacement vector fields (DVFs), the calculated 3D doses were accumulated using a mass-and energy congruent mapping method and compared to those measured by the TLDs at four typical locations. In the static case, TLD measurements agreed with all the algorithms by 1.8% at the center of the tumor volume and by 4.0% in the penumbra. In the deformable case, the phantom's deformation was reproduced within 1.1 mm. For the 3D dose calculated by Pinnacle, the total dose accumulated with the Elastix DVF agreed well to the TLD measurements with their differences <2.5% at four measured locations. When the VelocityAI DVF was used, their difference increased up to 11.8%. For the 3D dose calculated by EGSnrc/DOSXYZnrc, the total doses accumulated with the two DVFs were within 5.7% of the TLD measurements which are slightly over the rate of 5% for clinical acceptance. The detector-embedded deformable phantom allows radiation dose to be measured in a dynamic environment, similar to deforming lung tissues, supporting the validation of dose mapping and accumulation operations in regions with heterogeneous mass, and dose distributions.http://www.jmp.org.in/article.asp?issn=0971-6203;year=2016;volume=41;issue=2;spage=106;epage=114;aulast=ZhongAdaptive radiation therapy; dose accumulation; quality assurance |
| spellingShingle | Hualiang Zhong Jeffrey Adams Carri Glide-Hurst Hualin Zhang Haisen Li Indrin J Chetty Development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapy Journal of Medical Physics Adaptive radiation therapy; dose accumulation; quality assurance |
| title | Development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapy |
| title_full | Development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapy |
| title_fullStr | Development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapy |
| title_full_unstemmed | Development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapy |
| title_short | Development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapy |
| title_sort | development of a deformable dosimetric phantom to verify dose accumulation algorithms for adaptive radiotherapy |
| topic | Adaptive radiation therapy; dose accumulation; quality assurance |
| url | http://www.jmp.org.in/article.asp?issn=0971-6203;year=2016;volume=41;issue=2;spage=106;epage=114;aulast=Zhong |
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