Dosimetric effect of intrafraction motion and residual setup error for hypofractionated prostate intensity-modulated radiotherapy with online cone beam computed tomography image guidance.
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 me...
| Publicado en: | International Journal of Radiation Oncology, Biology, Physics Vol. 80; no. 2; pp. 453 - 462 |
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| Autores principales: | , , , , , |
| Formato: | Journal Article |
| Publicado: |
Pergamon Press - An Imprint of Elsevier Science
Jun2011
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=104891688&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 104891688 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 03603016 1ZQ jtl: International Journal of Radiation Oncology, Biology, Physics issn: 03603016 maglogo: N pubinfo: dt: Jun2011 vid: 80 iid: 2 pid: 2410 pub: Pergamon Press - An Imprint of Elsevier Science artinfo: ui: 104891688 NLM20646842 2011041358 10.1016/j.ijrobp.2010.02.033 NLM20646842 PMC3010484 104891688 ppf: 453 ppct: 9 formats: tig: atl: Dosimetric effect of intrafraction motion and residual setup error for hypofractionated prostate intensity-modulated radiotherapy with online cone beam computed tomography image guidance. aug: au: Adamson J Wu Q Yan D Adamson, Justus Wu, Qiuwen Yan, Di affil: Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan, USA sug: subj: Tomography, X-Ray Computed Methods Movement Prostatic Neoplasms Radiography Prostatic Neoplasms Radiotherapy Radiotherapy, Computer-Assisted Methods Radiotherapy, Conformal Methods Algorithms Radiation Dosage Gold Male Patient Positioning Prostate Radiography Prostatic Neoplasms Pathology Body Weights and Measures Male ab: 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. pubtype: Academic Journal doctype: Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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