Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device
<p>Abstract</p> <p>Background</p> <p>Set-up errors are an inherent part of radiation treatment process. Coverage of target volume is a direct function of set-up margins, which should be optimized to prevent inadvertent irradiation of adjacent normal tissues. The aim of...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2007-12-01
|
| Series: | Radiation Oncology |
| Online Access: | http://www.ro-journal.com/content/2/1/44 |
| _version_ | 1818690888971321344 |
|---|---|
| author | Devi P Reena Agarwal Jai Kadam Avinash Chopra Supriya Gupta Tejpal Ghosh-Laskar Sarbani Dinshaw Ketayun |
| author_facet | Devi P Reena Agarwal Jai Kadam Avinash Chopra Supriya Gupta Tejpal Ghosh-Laskar Sarbani Dinshaw Ketayun |
| author_sort | Devi P Reena |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Set-up errors are an inherent part of radiation treatment process. Coverage of target volume is a direct function of set-up margins, which should be optimized to prevent inadvertent irradiation of adjacent normal tissues. The aim of this study was to evaluate three-dimensional (3D) set-up errors and propose optimum margins for target volume coverage in head and neck radiotherapy.</p> <p>Methods</p> <p>The dataset consisted of 93 pairs of orthogonal simulator and corresponding portal images on which 558 point positions were measured to calculate translational displacement in 25 patients undergoing conventional head and neck radiotherapy with antero-lateral wedge pair technique. Mean displacements, population systematic (Σ) and random (σ) errors and 3D vector of displacement was calculated. Set-up margins were calculated using published margin recipes.</p> <p>Results</p> <p>The mean displacement in antero-posterior (AP), medio-lateral (ML) and supero-inferior (SI) direction was -0.25 mm (-6.50 to +7.70 mm), -0.48 mm (-5.50 to +7.80 mm) and +0.45 mm (-7.30 to +7.40 mm) respectively. Ninety three percent of the displacements were within 5 mm in all three cardinal directions. Population systematic (Σ) and random errors (σ) were 0.96, 0.98 and 1.20 mm and 1.94, 1.97 and 2.48 mm in AP, ML and SI direction respectively. The mean 3D vector of displacement was 3.84 cm. Using van Herk's formula, the clinical target volume to planning target volume margins were 3.76, 3.83 and 4.74 mm in AP, ML and SI direction respectively.</p> <p>Conclusion</p> <p>The present study report compares well with published set-up error data relevant to head and neck radiotherapy practice. The set-up margins were <5 mm in all directions. Caution is warranted against adopting generic margin recipes as different margin generating recipes lead to a different probability of target volume coverage.</p> |
| first_indexed | 2024-12-17T12:33:10Z |
| format | Article |
| id | doaj.art-7604cf42f42248519e7709c69ac7004b |
| institution | Directory Open Access Journal |
| issn | 1748-717X |
| language | English |
| last_indexed | 2024-12-17T12:33:10Z |
| publishDate | 2007-12-01 |
| publisher | BMC |
| record_format | Article |
| series | Radiation Oncology |
| spelling | doaj.art-7604cf42f42248519e7709c69ac7004b2022-12-21T21:48:27ZengBMCRadiation Oncology1748-717X2007-12-01214410.1186/1748-717X-2-44Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging deviceDevi P ReenaAgarwal JaiKadam AvinashChopra SupriyaGupta TejpalGhosh-Laskar SarbaniDinshaw Ketayun<p>Abstract</p> <p>Background</p> <p>Set-up errors are an inherent part of radiation treatment process. Coverage of target volume is a direct function of set-up margins, which should be optimized to prevent inadvertent irradiation of adjacent normal tissues. The aim of this study was to evaluate three-dimensional (3D) set-up errors and propose optimum margins for target volume coverage in head and neck radiotherapy.</p> <p>Methods</p> <p>The dataset consisted of 93 pairs of orthogonal simulator and corresponding portal images on which 558 point positions were measured to calculate translational displacement in 25 patients undergoing conventional head and neck radiotherapy with antero-lateral wedge pair technique. Mean displacements, population systematic (Σ) and random (σ) errors and 3D vector of displacement was calculated. Set-up margins were calculated using published margin recipes.</p> <p>Results</p> <p>The mean displacement in antero-posterior (AP), medio-lateral (ML) and supero-inferior (SI) direction was -0.25 mm (-6.50 to +7.70 mm), -0.48 mm (-5.50 to +7.80 mm) and +0.45 mm (-7.30 to +7.40 mm) respectively. Ninety three percent of the displacements were within 5 mm in all three cardinal directions. Population systematic (Σ) and random errors (σ) were 0.96, 0.98 and 1.20 mm and 1.94, 1.97 and 2.48 mm in AP, ML and SI direction respectively. The mean 3D vector of displacement was 3.84 cm. Using van Herk's formula, the clinical target volume to planning target volume margins were 3.76, 3.83 and 4.74 mm in AP, ML and SI direction respectively.</p> <p>Conclusion</p> <p>The present study report compares well with published set-up error data relevant to head and neck radiotherapy practice. The set-up margins were <5 mm in all directions. Caution is warranted against adopting generic margin recipes as different margin generating recipes lead to a different probability of target volume coverage.</p>http://www.ro-journal.com/content/2/1/44 |
| spellingShingle | Devi P Reena Agarwal Jai Kadam Avinash Chopra Supriya Gupta Tejpal Ghosh-Laskar Sarbani Dinshaw Ketayun Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device Radiation Oncology |
| title | Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device |
| title_full | Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device |
| title_fullStr | Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device |
| title_full_unstemmed | Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device |
| title_short | Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device |
| title_sort | assessment of three dimensional set up errors in conventional head and neck radiotherapy using electronic portal imaging device |
| url | http://www.ro-journal.com/content/2/1/44 |
| work_keys_str_mv | AT devipreena assessmentofthreedimensionalsetuperrorsinconventionalheadandneckradiotherapyusingelectronicportalimagingdevice AT agarwaljai assessmentofthreedimensionalsetuperrorsinconventionalheadandneckradiotherapyusingelectronicportalimagingdevice AT kadamavinash assessmentofthreedimensionalsetuperrorsinconventionalheadandneckradiotherapyusingelectronicportalimagingdevice AT choprasupriya assessmentofthreedimensionalsetuperrorsinconventionalheadandneckradiotherapyusingelectronicportalimagingdevice AT guptatejpal assessmentofthreedimensionalsetuperrorsinconventionalheadandneckradiotherapyusingelectronicportalimagingdevice AT ghoshlaskarsarbani assessmentofthreedimensionalsetuperrorsinconventionalheadandneckradiotherapyusingelectronicportalimagingdevice AT dinshawketayun assessmentofthreedimensionalsetuperrorsinconventionalheadandneckradiotherapyusingelectronicportalimagingdevice |