Dose to medium in head and neck radiotherapy: Clinical implications for target volume metrics
Background and purpose: In radiotherapy dose calculation, advanced type-B dose calculation algorithms can calculate dose to medium (Dm), as opposed to Type-B algorithms which compute dose to varying densities of water (Dw). We investigate the impact of Dm on calculated dose and target coverage metri...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2019-07-01
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| Series: | Physics and Imaging in Radiation Oncology |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2405631619300429 |
| _version_ | 1828859416637603840 |
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| author | Nicholas Hardcastle Atousa Montaseri Jenny Lydon Tomas Kron Glen Osbourne Georgina Casswell David Taylor Lisa Hall Lachlan McDowell |
| author_facet | Nicholas Hardcastle Atousa Montaseri Jenny Lydon Tomas Kron Glen Osbourne Georgina Casswell David Taylor Lisa Hall Lachlan McDowell |
| author_sort | Nicholas Hardcastle |
| collection | DOAJ |
| description | Background and purpose: In radiotherapy dose calculation, advanced type-B dose calculation algorithms can calculate dose to medium (Dm), as opposed to Type-B algorithms which compute dose to varying densities of water (Dw). We investigate the impact of Dm on calculated dose and target coverage metrics in head and neck cancer patients. Methods and materials: We reviewed 27 successfully treated (disease free at two-years post-(chemo)radiotherapy) human papillomavirus-associated (HPV) oropharyngeal cancer (ONC) patients treated with IMRT. Doses were calculated with Type-B and Linear Boltzman Transport Equation (LBTE) algorithms in a commercial treatment planning system, with the treated multi-leaf collimator patterns and monitor units. Coverage for primary Gross Tumour Volume (GTVp), high dose Planning Target Volume (PTV) (PTV_High), mandible within PTV_High (Mand ∩ PTV) and PTV_High excluding bone (PTV-bone) were compared between the algorithms. Results: Dose to 95% of PTV_High with LBTE was on average 1.1 Gy/1.7% lower than with Type-B (95%CI 1.5–1.9%, p < 0.0001). This magnitude was inversely linearly correlated with the relative volume of the PTV_High containing bone (pearson r = −0.81). Dose to 98% of the GTVp was 0.9 Gy/1.3% lower with LBTE compared with Type-B (95%CI 1.1–1.5%, p < 0.05). Dose to 98% of Mand ∩ PTV was on average 3.4 Gy/5.0% lower with LBTE than with Type-B (95%CI 4.6–5.4%, p < 0.0001). Conclusion: In OPC treated with IMRT, Dm results in significant reductions in dose to bone in high dose PTVs. Reported GTVp dose was reduced, but by a lower magnitude. Reduced coverage metrics should be expected for OPC patients treated with IMRT, with dose reductions limited to regions of bone. Keywords: Dose to medium, Acuros, Dose calculation, IMRT, Head and neck cancer, Linear boltzman transport equation |
| first_indexed | 2024-12-13T02:18:16Z |
| format | Article |
| id | doaj.art-7fe20c2be9bd41ce93ccd85e28f0ab87 |
| institution | Directory Open Access Journal |
| issn | 2405-6316 |
| language | English |
| last_indexed | 2024-12-13T02:18:16Z |
| publishDate | 2019-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Physics and Imaging in Radiation Oncology |
| spelling | doaj.art-7fe20c2be9bd41ce93ccd85e28f0ab872022-12-22T00:02:50ZengElsevierPhysics and Imaging in Radiation Oncology2405-63162019-07-01119297Dose to medium in head and neck radiotherapy: Clinical implications for target volume metricsNicholas Hardcastle0Atousa Montaseri1Jenny Lydon2Tomas Kron3Glen Osbourne4Georgina Casswell5David Taylor6Lisa Hall7Lachlan McDowell8Physical Sciences, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia; Corresponding author at: Physical Sciences, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne 3000, VIC, Australia.Physical Sciences, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, AustraliaPhysical Sciences, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, AustraliaPhysical Sciences, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria, AustraliaDepartment of Radiation Therapy, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, AustraliaDepartment of Radiation Oncology, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, AustraliaPhysical Sciences, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, AustraliaDepartment of Radiation Therapy, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, AustraliaDepartment of Radiation Oncology, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, Victoria 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria, AustraliaBackground and purpose: In radiotherapy dose calculation, advanced type-B dose calculation algorithms can calculate dose to medium (Dm), as opposed to Type-B algorithms which compute dose to varying densities of water (Dw). We investigate the impact of Dm on calculated dose and target coverage metrics in head and neck cancer patients. Methods and materials: We reviewed 27 successfully treated (disease free at two-years post-(chemo)radiotherapy) human papillomavirus-associated (HPV) oropharyngeal cancer (ONC) patients treated with IMRT. Doses were calculated with Type-B and Linear Boltzman Transport Equation (LBTE) algorithms in a commercial treatment planning system, with the treated multi-leaf collimator patterns and monitor units. Coverage for primary Gross Tumour Volume (GTVp), high dose Planning Target Volume (PTV) (PTV_High), mandible within PTV_High (Mand ∩ PTV) and PTV_High excluding bone (PTV-bone) were compared between the algorithms. Results: Dose to 95% of PTV_High with LBTE was on average 1.1 Gy/1.7% lower than with Type-B (95%CI 1.5–1.9%, p < 0.0001). This magnitude was inversely linearly correlated with the relative volume of the PTV_High containing bone (pearson r = −0.81). Dose to 98% of the GTVp was 0.9 Gy/1.3% lower with LBTE compared with Type-B (95%CI 1.1–1.5%, p < 0.05). Dose to 98% of Mand ∩ PTV was on average 3.4 Gy/5.0% lower with LBTE than with Type-B (95%CI 4.6–5.4%, p < 0.0001). Conclusion: In OPC treated with IMRT, Dm results in significant reductions in dose to bone in high dose PTVs. Reported GTVp dose was reduced, but by a lower magnitude. Reduced coverage metrics should be expected for OPC patients treated with IMRT, with dose reductions limited to regions of bone. Keywords: Dose to medium, Acuros, Dose calculation, IMRT, Head and neck cancer, Linear boltzman transport equationhttp://www.sciencedirect.com/science/article/pii/S2405631619300429 |
| spellingShingle | Nicholas Hardcastle Atousa Montaseri Jenny Lydon Tomas Kron Glen Osbourne Georgina Casswell David Taylor Lisa Hall Lachlan McDowell Dose to medium in head and neck radiotherapy: Clinical implications for target volume metrics Physics and Imaging in Radiation Oncology |
| title | Dose to medium in head and neck radiotherapy: Clinical implications for target volume metrics |
| title_full | Dose to medium in head and neck radiotherapy: Clinical implications for target volume metrics |
| title_fullStr | Dose to medium in head and neck radiotherapy: Clinical implications for target volume metrics |
| title_full_unstemmed | Dose to medium in head and neck radiotherapy: Clinical implications for target volume metrics |
| title_short | Dose to medium in head and neck radiotherapy: Clinical implications for target volume metrics |
| title_sort | dose to medium in head and neck radiotherapy clinical implications for target volume metrics |
| url | http://www.sciencedirect.com/science/article/pii/S2405631619300429 |
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