Dosimetric effect of intrafraction motion and residual setup error for hypofractionated prostate intensity-modulated radiotherapy with online cone beam computed tomography image guidance.

Hdl Handle:
http://hdl.handle.net/10147/207249
Title:
Dosimetric effect of intrafraction motion and residual setup error for hypofractionated prostate intensity-modulated radiotherapy with online cone beam computed tomography image guidance.
Authors:
Adamson, Justus; Wu, Qiuwen; Yan, Di
Affiliation:
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan,, USA.
Citation:
Int J Radiat Oncol Biol Phys. 2011 Jun 1;80(2):453-61. Epub 2010 Jun 18.
Journal:
International journal of radiation oncology, biology, physics
Issue Date:
1-Feb-2012
URI:
http://hdl.handle.net/10147/207249
DOI:
10.1016/j.ijrobp.2010.02.033
PubMed ID:
20646842
Abstract:
PURPOSE: To quantify the dosimetric effect and margins required to account for prostate intrafractional translation and residual setup error in a cone beam computed tomography (CBCT)-guided hypofractionated radiotherapy protocol. METHODS AND MATERIALS: Prostate position after online correction was measured during dose delivery using simultaneous kV fluoroscopy and posttreatment CBCT in 572 fractions to 30 patients. We reconstructed the dose distribution to the clinical tumor volume (CTV) using a convolution of the static dose with a probability density function (PDF) based on the kV fluoroscopy, and we calculated the minimum dose received by 99% of the CTV (D(99)). We compared reconstructed doses when the convolution was performed per beam, per patient, and when the PDF was created using posttreatment CBCT. We determined the minimum axis-specific margins to limit CTV D(99) reduction to 1%. RESULTS: For 3-mm margins, D(99) reduction was </=5% for 29/30 patients. Using post-CBCT rather than localizations at treatment delivery exaggerated dosimetric effects by ~47%, while there was no such bias between the dose convolved with a beam-specific and patient-specific PDF. After eight fractions, final cumulative D(99) could be predicted with a root mean square error of <1%. For 90% of patients, the required margins were </=2, 4, and 3 mm, with 70%, 40%, and 33% of patients requiring no right-left (RL), anteroposterior (AP), and superoinferior margins, respectively. CONCLUSIONS: For protocols with CBCT guidance, RL, AP, and SI margins of 2, 4, and 3 mm are sufficient to account for translational errors; however, the large variation in patient-specific margins suggests that adaptive management may be beneficial.
Language:
eng
MeSH:
Algorithms; Cone-Beam Computed Tomography/*methods; Dose Fractionation; Fiducial Markers; Gold; Humans; Male; *Movement; Patient Positioning; Prostate/radiography; Prostatic Neoplasms/pathology/*radiography/*radiotherapy; Radiotherapy Planning, Computer-Assisted/*methods; Radiotherapy, Intensity-Modulated/*methods; Tumor Burden
ISSN:
1879-355X (Electronic); 0360-3016 (Linking)

Full metadata record

DC FieldValue Language
dc.contributor.authorAdamson, Justusen_GB
dc.contributor.authorWu, Qiuwenen_GB
dc.contributor.authorYan, Dien_GB
dc.date.accessioned2012-02-01T10:03:04Z-
dc.date.available2012-02-01T10:03:04Z-
dc.date.issued2012-02-01T10:03:04Z-
dc.identifier.citationInt J Radiat Oncol Biol Phys. 2011 Jun 1;80(2):453-61. Epub 2010 Jun 18.en_GB
dc.identifier.issn1879-355X (Electronic)en_GB
dc.identifier.issn0360-3016 (Linking)en_GB
dc.identifier.pmid20646842en_GB
dc.identifier.doi10.1016/j.ijrobp.2010.02.033en_GB
dc.identifier.urihttp://hdl.handle.net/10147/207249-
dc.description.abstractPURPOSE: To quantify the dosimetric effect and margins required to account for prostate intrafractional translation and residual setup error in a cone beam computed tomography (CBCT)-guided hypofractionated radiotherapy protocol. METHODS AND MATERIALS: Prostate position after online correction was measured during dose delivery using simultaneous kV fluoroscopy and posttreatment CBCT in 572 fractions to 30 patients. We reconstructed the dose distribution to the clinical tumor volume (CTV) using a convolution of the static dose with a probability density function (PDF) based on the kV fluoroscopy, and we calculated the minimum dose received by 99% of the CTV (D(99)). We compared reconstructed doses when the convolution was performed per beam, per patient, and when the PDF was created using posttreatment CBCT. We determined the minimum axis-specific margins to limit CTV D(99) reduction to 1%. RESULTS: For 3-mm margins, D(99) reduction was </=5% for 29/30 patients. Using post-CBCT rather than localizations at treatment delivery exaggerated dosimetric effects by ~47%, while there was no such bias between the dose convolved with a beam-specific and patient-specific PDF. After eight fractions, final cumulative D(99) could be predicted with a root mean square error of <1%. For 90% of patients, the required margins were </=2, 4, and 3 mm, with 70%, 40%, and 33% of patients requiring no right-left (RL), anteroposterior (AP), and superoinferior margins, respectively. CONCLUSIONS: For protocols with CBCT guidance, RL, AP, and SI margins of 2, 4, and 3 mm are sufficient to account for translational errors; however, the large variation in patient-specific margins suggests that adaptive management may be beneficial.en_GB
dc.language.isoengen_GB
dc.subject.meshAlgorithmsen_GB
dc.subject.meshCone-Beam Computed Tomography/*methodsen_GB
dc.subject.meshDose Fractionationen_GB
dc.subject.meshFiducial Markersen_GB
dc.subject.meshGolden_GB
dc.subject.meshHumansen_GB
dc.subject.meshMaleen_GB
dc.subject.mesh*Movementen_GB
dc.subject.meshPatient Positioningen_GB
dc.subject.meshProstate/radiographyen_GB
dc.subject.meshProstatic Neoplasms/pathology/*radiography/*radiotherapyen_GB
dc.subject.meshRadiotherapy Planning, Computer-Assisted/*methodsen_GB
dc.subject.meshRadiotherapy, Intensity-Modulated/*methodsen_GB
dc.subject.meshTumor Burdenen_GB
dc.titleDosimetric effect of intrafraction motion and residual setup error for hypofractionated prostate intensity-modulated radiotherapy with online cone beam computed tomography image guidance.en_GB
dc.contributor.departmentDepartment of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan,, USA.en_GB
dc.identifier.journalInternational journal of radiation oncology, biology, physicsen_GB
dc.description.provinceLeinster-

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