Image guided radiation therapy for bladder cancer: Assessment of bladder motion using implanted fiducial markers Journal Article
| Authors: | Biancia, C. D.; Yorke, E.; Kollmeier, M. A. |
| Article Title: | Image guided radiation therapy for bladder cancer: Assessment of bladder motion using implanted fiducial markers |
| Abstract: | Purpose: To determine bladder wall position variability during external beam radiation therapy (EBRT) for bladder cancer with intravesical fiducial markers using 2-dimensional (2D) and volumetric (3D) imaging registration. Methods and Materials: Twenty T2-4aN0-1 bladder cancer patients underwent definitive EBRT with concurrent chemotherapy between May 2001 and January 2012, and had intravesical fiducial marker placement before simulation. Computed tomographic (CT)-based treatment planning was used for an initial phase to deliver 45 Gy (1.8 Gy/fraction) to the bladder and pelvic lymphatics followed by a boost to the involved bladder wall for an additional 21.6 Gy (1.8 Gy/fraction). Orthogonal kilovoltage radiograph images (34-37 images/patient) were obtained daily, registered with digitally reconstructed radiographs from the planning scan. Translational corrections were made daily. A kilovoltage cone-beam CT (kVCBCT) was acquired weekly and its registration with the planning scan was compared with that day's 2D registration results. Results: Of 739 treatments, 6% resulted in ≥. 15 mm displacement in 1 or more directions and 26% resulted in ≥. 10 mm displacement in 1 or more directions. Based on 2D registrations, the average millimeter difference between bony registration and fiducial marker registration (BR-FMR) in the right-left (RL) (R. +), anterior-posterior (AP) (A. +), and superior-inferior (SI) (I. +) directions were: 0.5 ± 1.0 (range, -2.0 to +. 3.8), 1.7 ± 4.4 (range, -8.1 to +. 13.5) and -3.7 ± 5.8 (range, -16.8 to +. 8.3), respectively. For kVCBCT registrations, the average mm difference in the RL, AP, and SI directions were 0.3 ± 2.1 (range, -2.4 to +. 5.1), 3.1 ± 5.9 (range, -2.9 to +. 13.3) and -4.8 ± 8.0 (range, -16.4 to +. 9.5), respectively. Conclusions: Using intravesical fiducial markers, the largest difference in bladder motion based BR-FMR differences was in the superior-inferior direction. Because fiducial markers are target surrogates, setup using bony anatomy alone can lead to target displacements up to 13.5 mm anteriorly and 16.8 mm superiorly. This confirms a 1.5-1.7 cm minimum in planning target margins. These findings suggest a significant advantage in using intravesical fiducial markers to determine daily translational corrections. © 2014 American Society for Radiation Oncology. |
| Keywords: | adult; clinical article; aged; treatment planning; cancer radiotherapy; cancer staging; outcome assessment; computer assisted tomography; bladder cancer; radiation dose fractionation; three dimensional imaging; clinical effectiveness; external beam radiotherapy; bladder function; volumetry; bladder wall; pelvis radiography; image guided radiotherapy; fiducial marker; human; male; female; priority journal; article; bladder motion |
| Journal Title: | Practical Radiation Oncology |
| Volume: | 4 |
| Issue: | 2 |
| ISSN: | 1879-8519 |
| Publisher: | Elsevier Inc. |
| Date Published: | 2014-03-01 |
| Start Page: | 108 |
| End Page: | 115 |
| Language: | English |
| DOI: | 10.1016/j.prro.2013.07.008 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Export Date: 2 April 2014 -- Source: Scopus |
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