Quantification of the margin required for treating intraprostatic lesions

Advances in magnetic resonance imaging (MRI) sequences allow physicians to define the dominant intraprostatic lesion (IPL) in prostate radiation therapy treatments allowing for dose escalation and potentially increased tumor control. This work quantifies the margin required around the MRI‐defined IP...

Full description

Saved in:
Bibliographic Details
Published in:Journal of applied clinical medical physics 2016-05, Vol.17 (3), p.304-312
Main Authors: Studenski, Matthew T., Valenciaga, Yanisley, Abramowitz, Matthew C., Stoyanova, Radka, Bossart, Elizabeth, Dogan, Nesrin, Pollack, Alan
Format: Article
Language:English
Subjects:
Bladder
Cancer therapies
Cone-Beam Computed Tomography - methods
Dose Fractionation
Humans
Image Processing, Computer-Assisted - methods
IMRT
intraprostatic lesion
Male
MRI
NMR
Nuclear magnetic resonance
Patients
Planning
Prostate cancer
prostate radiation therapy
Prostatic Neoplasms - diagnostic imaging
Prostatic Neoplasms - pathology
Prostatic Neoplasms - radiotherapy
Radiation Oncology Physics
Radiation therapy
Radiotherapy Planning, Computer-Assisted - methods
Radiotherapy, Image-Guided - methods
Radiotherapy, Intensity-Modulated - methods
Retrospective Studies
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Advances in magnetic resonance imaging (MRI) sequences allow physicians to define the dominant intraprostatic lesion (IPL) in prostate radiation therapy treatments allowing for dose escalation and potentially increased tumor control. This work quantifies the margin required around the MRI‐defined IPL accounting for both prostate motion and deformation. Ten patients treated with a simultaneous integrated intraprostatic boost (SIIB) were retrospectively selected and replanned with incremental 1 mm margins from 0‐5 mm around the IPL to determine if there were any significant differences in dosimetric parameters. Sensitivity analysis was then performed accounting for random and systematic uncertainties in both prostate motion and deformation to ensure adequate dose was delivered to the IPL. Prostate deformation was assessed using daily CBCT imaging and implanted fiducial markers. The average IPL volume without margin was 2.3% of the PTV volume and increased to 11.8% with a 5 mm margin. Despite these changes in volume, the only statistically significant dosimetric difference was found for the PTV maximum dose, which increased with increasing margin. The sensitivity analysis demonstrated that a 3.0 mm margin ensures >95% IPL coverage accounting for both motion and deformation. We found that a margin of 3.0 mm around the MRI defined IPL is sufficient to account for random and systematic errors in IPL position for the majority of cases. PACS number(s): 87.55.de
ISSN:1526-9914
1526-9914
DOI:10.1120/jacmp.v17i3.6089