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Factors Affecting Isocenter Displacement and Planning Target Volume Margin for Patients With Rectal Cancer Receiving Radiation Therapy

PURPOSE: Setup errors are inherent in the process of daily radiation therapy (RT) delivery. Pelvic RT for rectal cancer is one of the body sites associated with the largest shift among other body sites. This study aimed to evaluate interfraction random and systematic errors and hence propose the opt...

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Autores principales: Mohamed, Reham, Elawadi, Abousaleh Abousaleh, Alkhanein, Nwaf, Alharth, Muslihah, Asiri, Mushabbab
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9677216/
https://www.ncbi.nlm.nih.gov/pubmed/36420207
http://dx.doi.org/10.1016/j.adro.2022.101060
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author Mohamed, Reham
Elawadi, Abousaleh Abousaleh
Alkhanein, Nwaf
Alharth, Muslihah
Asiri, Mushabbab
author_facet Mohamed, Reham
Elawadi, Abousaleh Abousaleh
Alkhanein, Nwaf
Alharth, Muslihah
Asiri, Mushabbab
author_sort Mohamed, Reham
collection PubMed
description PURPOSE: Setup errors are inherent in the process of daily radiation therapy (RT) delivery. Pelvic RT for rectal cancer is one of the body sites associated with the largest shift among other body sites. This study aimed to evaluate interfraction random and systematic errors and hence propose the optimum planning target volume (PTV) in patients with rectal cancer. METHODS AND MATERIALS: Translational and angular isocenter displacements were retrospectively collected for 189 patients. Random and systematic errors were determined, and then the PTV margin was computed. Effect of positioning, body mass index (BMI), and type of immobilization were studied. Portal images before and after online correction were used to define PTV for no-daily image-guided radiotherapy (IGRT) and daily IGRT respectively. RESULTS: Before the online correction, the systematic errors were 2.5, 2.8, and 3.0 mm for superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions, respectively, compared with 2.1, 1.7, and 1.8 mm after online correction. The random errors were 6.2, 7.4, and 8.2 mm in SI, RL, and AP, respectively, before online correction, compared with 4, 4.2, and 4.5 mm after online correction. The recommended PTV margin was 0.7 and 1.0 cm for daily IGRT and no-daily IGRT, respectively. The prone position and BMI >30 kg/m(2) warrant higher margins in no-daily IGRT cases, 1.2 and 1.4 cm, respectively. CONCLUSIONS: The prone position, BMI >30 kg/m(2), and belly board device are associated with larger daily setup errors warranting higher PTV margins for no-daily IGRT; however, that can be avoided by using daily IGRT.
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spelling pubmed-96772162022-11-22 Factors Affecting Isocenter Displacement and Planning Target Volume Margin for Patients With Rectal Cancer Receiving Radiation Therapy Mohamed, Reham Elawadi, Abousaleh Abousaleh Alkhanein, Nwaf Alharth, Muslihah Asiri, Mushabbab Adv Radiat Oncol Scientific Article PURPOSE: Setup errors are inherent in the process of daily radiation therapy (RT) delivery. Pelvic RT for rectal cancer is one of the body sites associated with the largest shift among other body sites. This study aimed to evaluate interfraction random and systematic errors and hence propose the optimum planning target volume (PTV) in patients with rectal cancer. METHODS AND MATERIALS: Translational and angular isocenter displacements were retrospectively collected for 189 patients. Random and systematic errors were determined, and then the PTV margin was computed. Effect of positioning, body mass index (BMI), and type of immobilization were studied. Portal images before and after online correction were used to define PTV for no-daily image-guided radiotherapy (IGRT) and daily IGRT respectively. RESULTS: Before the online correction, the systematic errors were 2.5, 2.8, and 3.0 mm for superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions, respectively, compared with 2.1, 1.7, and 1.8 mm after online correction. The random errors were 6.2, 7.4, and 8.2 mm in SI, RL, and AP, respectively, before online correction, compared with 4, 4.2, and 4.5 mm after online correction. The recommended PTV margin was 0.7 and 1.0 cm for daily IGRT and no-daily IGRT, respectively. The prone position and BMI >30 kg/m(2) warrant higher margins in no-daily IGRT cases, 1.2 and 1.4 cm, respectively. CONCLUSIONS: The prone position, BMI >30 kg/m(2), and belly board device are associated with larger daily setup errors warranting higher PTV margins for no-daily IGRT; however, that can be avoided by using daily IGRT. Elsevier 2022-09-02 /pmc/articles/PMC9677216/ /pubmed/36420207 http://dx.doi.org/10.1016/j.adro.2022.101060 Text en © 2022 The Author(s) https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Scientific Article
Mohamed, Reham
Elawadi, Abousaleh Abousaleh
Alkhanein, Nwaf
Alharth, Muslihah
Asiri, Mushabbab
Factors Affecting Isocenter Displacement and Planning Target Volume Margin for Patients With Rectal Cancer Receiving Radiation Therapy
title Factors Affecting Isocenter Displacement and Planning Target Volume Margin for Patients With Rectal Cancer Receiving Radiation Therapy
title_full Factors Affecting Isocenter Displacement and Planning Target Volume Margin for Patients With Rectal Cancer Receiving Radiation Therapy
title_fullStr Factors Affecting Isocenter Displacement and Planning Target Volume Margin for Patients With Rectal Cancer Receiving Radiation Therapy
title_full_unstemmed Factors Affecting Isocenter Displacement and Planning Target Volume Margin for Patients With Rectal Cancer Receiving Radiation Therapy
title_short Factors Affecting Isocenter Displacement and Planning Target Volume Margin for Patients With Rectal Cancer Receiving Radiation Therapy
title_sort factors affecting isocenter displacement and planning target volume margin for patients with rectal cancer receiving radiation therapy
topic Scientific Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9677216/
https://www.ncbi.nlm.nih.gov/pubmed/36420207
http://dx.doi.org/10.1016/j.adro.2022.101060
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