TY - JOUR
T1 - Reduced motion and improved rectal dosimetry through endorectal immobilization for prostate stereotactic body radiotherapy
AU - De Leon, Jeremiah
AU - Jameson, Michael G.
AU - Rivest-Henault, David
AU - Keats, Sarah
AU - Rai, Robba
AU - Arumugam, Sankar
AU - Wilton, Lee
AU - Ngo, Diana
AU - Liney, Gary
AU - Moses, Daniel
AU - Dowling, Jason
AU - Martin, Jarad
AU - Sidhom, Mark
N1 - Publisher Copyright:
© 2019 The Authors.
PY - 2019
Y1 - 2019
N2 - Objective: PROMETHEUS (ACTRN12615000223538) is a multicentre clinical trial investigating the feasibility of 19 Gy in 2 fractions of stereotactic body radiotherapy (SBRT) as a boost technique for prostate cancer. The objective of this substudy was to evaluate intrafraction motion using cine MRI and assess the dosimetric impact of using a rectal displacement device (RDD). Methods: The initial 10 patients recruited underwent planning CT and MRI, with and without a RDD. Cine MRI images were captured using an interleaved T2 HASTE sequence in sagittal and axial planes with a temporal resolution of 5.2 s acquired over 4.3 min. Points of interest (POIs) were defined and a validated tracking algorithm measured displacement of these points over the 4.3 min in the anteroposterior, superior-inferior and left-right directions. Plans were generated with and without a RDD to examine the impact on dosimetry. Results: There was an overall trend for increasing displacement in all directions as time progressed when no RDD was in situ . pointsof interest remained comparatively stable with the RDD. In the sagittal plane, the RDD resulted in statistically significant improvement in the range of anteroposterior displacement for the rectal wall, anterior prostate, prostate apex and base. Dosimetrically, the use of a RDD significantly reduced rectal V16, V14 and Dmax, as well as the percentage of posterior rectal wall receiving 8.5 Gy. Conclusion: The RDD used in stereotactic prostate radiotherapy leads to reduced intrafraction motion of the prostate and rectum, with increasing improvement with time. It also results in significant improvement in rectal wall dosimetry. Advances in knowledge: It was found that the rectal displacement device improved prostate stabilization significantly, improved rectum stabilization and dosimetry significantly. The rectal displacement device did not improve target volume dosimetry.
AB - Objective: PROMETHEUS (ACTRN12615000223538) is a multicentre clinical trial investigating the feasibility of 19 Gy in 2 fractions of stereotactic body radiotherapy (SBRT) as a boost technique for prostate cancer. The objective of this substudy was to evaluate intrafraction motion using cine MRI and assess the dosimetric impact of using a rectal displacement device (RDD). Methods: The initial 10 patients recruited underwent planning CT and MRI, with and without a RDD. Cine MRI images were captured using an interleaved T2 HASTE sequence in sagittal and axial planes with a temporal resolution of 5.2 s acquired over 4.3 min. Points of interest (POIs) were defined and a validated tracking algorithm measured displacement of these points over the 4.3 min in the anteroposterior, superior-inferior and left-right directions. Plans were generated with and without a RDD to examine the impact on dosimetry. Results: There was an overall trend for increasing displacement in all directions as time progressed when no RDD was in situ . pointsof interest remained comparatively stable with the RDD. In the sagittal plane, the RDD resulted in statistically significant improvement in the range of anteroposterior displacement for the rectal wall, anterior prostate, prostate apex and base. Dosimetrically, the use of a RDD significantly reduced rectal V16, V14 and Dmax, as well as the percentage of posterior rectal wall receiving 8.5 Gy. Conclusion: The RDD used in stereotactic prostate radiotherapy leads to reduced intrafraction motion of the prostate and rectum, with increasing improvement with time. It also results in significant improvement in rectal wall dosimetry. Advances in knowledge: It was found that the rectal displacement device improved prostate stabilization significantly, improved rectum stabilization and dosimetry significantly. The rectal displacement device did not improve target volume dosimetry.
UR - http://www.scopus.com/inward/record.url?scp=85066336910&partnerID=8YFLogxK
U2 - 10.1259/bjr.20190056
DO - 10.1259/bjr.20190056
M3 - Article
C2 - 30912956
AN - SCOPUS:85066336910
SN - 0007-1285
VL - 92
SP - 1
EP - 8
JO - British Journal of Radiology
JF - British Journal of Radiology
IS - 1098
M1 - 20190056
ER -