The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical Structures
Radiotherapy dose calculation requires accurate Computed Tomography (CT) imaging while tissue delineation may necessitate the use of contrast agents (CA). Acquiring these two sets is a common practice in radiotherapy. This study aims to evaluate the effect of CA on the dose calculations. Two hundred...
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MDPI AG
2021-09-01
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| author | A. A. Elawadi Safa AlMohsen Reham AlGendy Hosam Allazkani Reham A. Mohamed Hossam AlAssaf Andrew Nisbet Mukhtar Alshanqity |
| author_facet | A. A. Elawadi Safa AlMohsen Reham AlGendy Hosam Allazkani Reham A. Mohamed Hossam AlAssaf Andrew Nisbet Mukhtar Alshanqity |
| author_sort | A. A. Elawadi |
| collection | DOAJ |
| description | Radiotherapy dose calculation requires accurate Computed Tomography (CT) imaging while tissue delineation may necessitate the use of contrast agents (CA). Acquiring these two sets is a common practice in radiotherapy. This study aims to evaluate the effect of CA on the dose calculations. Two hundred and twenty-six volumetric modulated arc therapy (VMAT) patients that had planning CT with contrast (CCT) and non-contrast CT (NCCT) of different cancer sites (e.g., brain, head, and neck (H&N), chest, abdomen, and pelvis) were evaluated. Treatment plans were recalculated using CCT, then compared to NCCT. The variation in Hounsfield units (HU) and dose distributions for critical structures and target volumes were analyzed using mean HU, mean and maximum relative dose values, D<sub>2%</sub>, D<sub>98%</sub>, and 3D gamma analysis. HU variations were statistically significant for most structures. However, this was not clinically significant as the difference in mean HU values was within 30 HU for soft tissue and 50 HU for lungs. Variation in target volumes’ D<sub>2%</sub> and D<sub>98%</sub> were insignificant for all sites except brain and nasopharynx. Dose maximum differences were within 2% for the majority of critical structures and target volumes. 3D gamma analysis results revealed that majority of plans satisfied the 2% and 2 mm criteria. CCT may be acquired for VMAT radiotherapy planning purposes instead of NCCT, since there is no clinically significant difference in dose calculations based on either image set. |
| first_indexed | 2024-03-10T07:56:16Z |
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| language | English |
| last_indexed | 2024-03-10T07:56:16Z |
| publishDate | 2021-09-01 |
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| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-97d7343898354a4b932ec46e3980a5372023-11-22T11:51:23ZengMDPI AGApplied Sciences2076-34172021-09-011118835510.3390/app11188355The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical StructuresA. A. Elawadi0Safa AlMohsen1Reham AlGendy2Hosam Allazkani3Reham A. Mohamed4Hossam AlAssaf5Andrew Nisbet6Mukhtar Alshanqity7King Fahad Medical City, Riyadh 12231, Saudi ArabiaKing Fahad Medical City, Riyadh 12231, Saudi ArabiaKing Fahad Medical City, Riyadh 12231, Saudi ArabiaKing Fahad Medical City, Riyadh 12231, Saudi ArabiaNational Cancer Institute, Cairo University, Cairo 11796, EgyptKing Fahad Medical City, Riyadh 12231, Saudi ArabiaDepartment of Medical Physics & Biomedical Engineering, University College London, London WC1E 6BT, UKKing Fahad Medical City, Riyadh 12231, Saudi ArabiaRadiotherapy dose calculation requires accurate Computed Tomography (CT) imaging while tissue delineation may necessitate the use of contrast agents (CA). Acquiring these two sets is a common practice in radiotherapy. This study aims to evaluate the effect of CA on the dose calculations. Two hundred and twenty-six volumetric modulated arc therapy (VMAT) patients that had planning CT with contrast (CCT) and non-contrast CT (NCCT) of different cancer sites (e.g., brain, head, and neck (H&N), chest, abdomen, and pelvis) were evaluated. Treatment plans were recalculated using CCT, then compared to NCCT. The variation in Hounsfield units (HU) and dose distributions for critical structures and target volumes were analyzed using mean HU, mean and maximum relative dose values, D<sub>2%</sub>, D<sub>98%</sub>, and 3D gamma analysis. HU variations were statistically significant for most structures. However, this was not clinically significant as the difference in mean HU values was within 30 HU for soft tissue and 50 HU for lungs. Variation in target volumes’ D<sub>2%</sub> and D<sub>98%</sub> were insignificant for all sites except brain and nasopharynx. Dose maximum differences were within 2% for the majority of critical structures and target volumes. 3D gamma analysis results revealed that majority of plans satisfied the 2% and 2 mm criteria. CCT may be acquired for VMAT radiotherapy planning purposes instead of NCCT, since there is no clinically significant difference in dose calculations based on either image set.https://www.mdpi.com/2076-3417/11/18/8355contrast agentradiotherapyCT simulationdose calculationVMAT |
| spellingShingle | A. A. Elawadi Safa AlMohsen Reham AlGendy Hosam Allazkani Reham A. Mohamed Hossam AlAssaf Andrew Nisbet Mukhtar Alshanqity The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical Structures Applied Sciences contrast agent radiotherapy CT simulation dose calculation VMAT |
| title | The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical Structures |
| title_full | The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical Structures |
| title_fullStr | The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical Structures |
| title_full_unstemmed | The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical Structures |
| title_short | The Effect of Contrast Agents on Dose Calculations of Volumetric Modulated Arc Radiotherapy Plans for Critical Structures |
| title_sort | effect of contrast agents on dose calculations of volumetric modulated arc radiotherapy plans for critical structures |
| topic | contrast agent radiotherapy CT simulation dose calculation VMAT |
| url | https://www.mdpi.com/2076-3417/11/18/8355 |
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