title: BrachyView: Combining LDR seed positions with transrectal ultrasound imaging in a prostate gel phantom.
abstract: OBJECTIVE
  BrachyView is a novel in-body imaging system which aims to provide LDR brachytherapy seeds position reconstruction within the prostate in real-time. The first prototype is presented in this study: the probe consists of a gamma camera featuring three single cone pinhole collimators embedded in a tungsten tube, above three, high resolution pixelated detectors (Timepix).
  
  
  METHODS
  The prostate was imaged with a TRUS system using a sagittal crystal with a 2.5mm slice thickness. Eleven needles containing a total of thirty 0.508U125I seeds were implanted under ultrasound guidance. A CT scan was used to localise the seed positions, as well as provide a reference when performing the image co-registration between the BrachyView coordinate system and the TRUS coordinate system. An in-house visualisation software interface was developed to provide a quantitative 3D reconstructed prostate based on the TRUS images and co-registered with the LDR seeds in situ. A rigid body image registration was performed between the BrachyView and TRUS systems, with the BrachyView and CT-derived source locations compared.
  
  
  RESULTS
  The reconstructed seed positions determined by the BrachyView probe showed a maximum discrepancy of 1.78mm, with 75% of the seeds reconstructed within 1mm of their nominal location. An accurate co-registration between the BrachyView and TRUS coordinate system was established.
  
  
  CONCLUSIONS
  The BrachyView system has shown its ability to reconstruct all implanted LDR seeds within a tissue equivalent prostate gel phantom, providing both anatomical and seed position information in a single interface.
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Australia. Electronic address: anatoly@uow.edu.au.
authors.forename: S
authors.initials: S
authors.lastname: Alnaghy
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Australia.
authors.forename: D L
authors.initials: DL
authors.lastname: Cutajar
authors.affiliation: St George Cancer Care Centre, St George Hospital, Kogarah, New South Wales, Australia.
authors.forename: J A
authors.initials: JA
authors.lastname: Bucci
authors.affiliation: Advanced Computer System Pty Ltd, Rome, Italy.
authors.forename: K
authors.initials: K
authors.lastname: Enari
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Safavi-Naeini
authors.affiliation: Advanced Computer System Pty Ltd, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Favoino
authors.affiliation: Advanced Computer System Pty Ltd, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Tartaglia
authors.affiliation: Advanced Computer System Pty Ltd, Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Carriero
authors.affiliation: Institute of Experimental and Applied Physics, Czech Technical University of Prague, Prague, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Jakubek
authors.affiliation: Institute of Experimental and Applied Physics, Czech Technical University of Prague, Prague, Czech Republic.
authors.forename: S
authors.initials: S
authors.lastname: Pospisil
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Lerch
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Australia.
authors.forename: A B
authors.initials: AB
authors.lastname: Rosenfeld
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Australia. Electronic address: marcop@uow.edu.au.
authors.forename: M
authors.initials: M
authors.lastname: Petasecca
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation*; D005782:Gels; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D019047:Phantoms, Imaging; D011467:Prostate / Q000000981:diagnostic imaging* / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D061089:Radiotherapy, Image-Guided / Q000295:instrumentation*; D012007:Rectum; D014463:Ultrasonography / Q000295:instrumentation*
chemical_list: D005782:Gels
keywords: Brachytherapy; Image fusion; In-vivo dosimetry