title: Seminal vesicle intrafraction motion analysed with cinematic magnetic resonance imaging.
abstract: OBJECTIVE
  This study analyses seminal vesicle displacement relative to the prostate and in relation to treatment time.
  
  
  METHODS
  A group of eleven patients undergoing prostate cancer radiotherapy were imaged with a continuous 3 T cine-MRI in the standard treatment setup position. Four images were recorded every 4 seconds for 15 minutes in the sagittal plane and every 6.5 seconds for 12 minutes in the coronal plane. The prostate gland and seminal vesicles were contoured on each MRI image. The coordinates of the centroid of the prostate and seminal vesicles on each image was analysed for displacement against time. Displacements between the 2.5 percentile and 97.5 percentile (i.e. the 2.5% trimmed range) for prostate and seminal vesicle centroid displacements were measured for 3, 5, 10 and 15 minutes time intervals in the anterior-posterior (AP), left-right (LR) and superior-inferior (SI) directions. Real time prostate and seminal vesicle displacement was compared for individual patients.
  
  
  RESULTS
  The 2.5% trimmed range for 3, 5, 10 and 15 minutes for the seminal vesicle centroids in the SI direction measured 4.7 mm; 5.8 mm; 6.5 mm and 7.2 mm respectively. In the AP direction, it was 4.0 mm, 4.5 mm, 6.5 mm, and 7.0 mm. In the LR direction for 3, 5 and 10 minutes; for the left seminal vesicle, it was 2.7 mm, 2.8 mm, 3.4 mm and for the right seminal vesicle, it was 3.4 mm, 3.3 mm, and 3.4 mm. The correlation between the real-time prostate and seminal vesicle displacement varied substantially between patients indicating that the relationship between prostate displacement and seminal vesicles displacement is patient specific with the majority of the patients not having a strong relationship.
  
  
  CONCLUSIONS
  Our study shows that seminal vesicle motion increases with treatment time, and that the prostate and seminal vesicle centroids do not move in unison in real time, and that an additional margin is required for independent seminal vesicle motion if treatment localisation is to the prostate.
authors.affiliation: Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia. suki.gill@petermac.org.
authors.forename: Suki
authors.initials: S
authors.lastname: Gill
authors.forename: Kim
authors.initials: K
authors.lastname: Dang
authors.forename: Chris
authors.initials: C
authors.lastname: Fox
authors.forename: Mathias
authors.initials: M
authors.lastname: Bressel
authors.forename: Tomas
authors.initials: T
authors.lastname: Kron
authors.forename: Noelene
authors.initials: N
authors.lastname: Bergen
authors.forename: Nick
authors.initials: N
authors.lastname: Ferris
authors.forename: Rebecca
authors.initials: R
authors.lastname: Owen
authors.forename: Sarat
authors.initials: S
authors.lastname: Chander
authors.forename: Keen Hun
authors.initials: KH
authors.lastname: Tai
authors.forename: Farshad
authors.initials: F
authors.lastname: Foroudi
mesh_terms: D016477:Artifacts; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009038:Motion; D011471:Prostatic Neoplasms / Q000473:pathology*; D012669:Seminal Vesicles / Q000473:pathology*
references.citation: Clin Oncol (R Coll Radiol). 2012 Oct;24(8):e93-9
references.pmid: 22694787
references.citation: Radiat Oncol. 2012 Aug 13;7:139
references.pmid: 22889144
references.citation: Int J Radiat Oncol Biol Phys. 2013 Mar 1;85(3):700-6
references.pmid: 22795802
references.citation: Int J Radiat Oncol Biol Phys. 2009 Mar 1;73(3):935-43
references.pmid: 19111401
references.citation: J Radiat Res. 2011;52(2):199-207
references.pmid: 21436610
references.citation: Int J Radiat Oncol Biol Phys. 1994 Sep 30;30(2):323-9
references.pmid: 7523343
references.citation: Radiat Oncol. 2011 Oct 28;6:145
references.pmid: 22035354
references.citation: Int J Radiat Oncol Biol Phys. 1999 Jun 1;44(3):525-33
references.pmid: 10348281
references.citation: Int J Radiat Oncol Biol Phys. 2008 Jul 1;71(3):813-20
references.pmid: 18207664
references.citation: Br J Radiol. 2012 Jul;85(1015):1011-7
references.pmid: 22253345
references.citation: Int J Radiat Oncol Biol Phys. 2012 Sep 1;84(1):125-9
references.pmid: 22330997
references.citation: Int J Radiat Oncol Biol Phys. 2005 Jun 1;62(2):406-17
references.pmid: 15890582
references.citation: Int J Radiat Oncol Biol Phys. 2009 Feb 1;73(2):334-40
references.pmid: 19147014
references.citation: Int J Radiat Oncol Biol Phys. 2002 Oct 1;54(2):568-75
references.pmid: 12243837
references.citation: Am J Clin Oncol. 2010 Feb;33(1):11-6
references.pmid: 19730351
references.citation: Semin Radiat Oncol. 2004 Jan;14(1):52-64
references.pmid: 14752733
references.citation: Int J Radiat Oncol Biol Phys. 2010 Jul 15;77(4):1072-8
references.pmid: 19783378