title: Quantitative ultrasound imaging of therapy response in bladder cancer in vivo.
abstract: OBJECTIVE
  Quantitative ultrasound (QUS) was investigated to monitor bladder cancer treatment response in vivo and to evaluate tumor cell death from combined treatments using ultrasound-stimulated microbubbles and radiation therapy.
  
  
  METHODS
  Tumor-bearing mice (n=45), with bladder cancer xenografts (HT- 1376) were exposed to 9 treatment conditions consisting of variable concentrations of ultrasound-stimulated Definity microbubbles [nil, low (1%), high (3%)], combined with single fractionated doses of radiation (0 Gy, 2 Gy, 8 Gy). High frequency (25 MHz) ultrasound was used to collect the raw radiofrequency (RF) data of the backscatter signal from tumors prior to, and 24 hours after treatment in order to obtain QUS parameters. The calculated QUS spectral parameters included the mid-band fit (MBF), and 0-MHz intercept (SI) using a linear regression analysis of the normalized power spectrum.
  
  
  CONCLUSIONS
  There were maximal increases in QUS parameters following treatments with high concentration microbubbles combined with 8 Gy radiation: (ΔMBF = +6.41 ± 1.40 (±SD) dBr and SI= + 7.01 ± 1.20 (±SD) dBr. Histological data revealed increased cell death, and a reduction in nuclear size with treatments, which was mirrored by changes in quantitative ultrasound parameters. QUS demonstrated markers to detect treatment effects in bladder tumors in vivo.
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; Sheffield Hallam University, Centre for Health and Social Care Research, Sheffield UK.
authors.forename: William T
authors.initials: WT
authors.lastname: Tran
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; University of Toronto, Department of Medical Biophysics, Toronto Canada.
authors.forename: Lakshmanan
authors.initials: L
authors.lastname: Sannachi
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; Ryerson University, Department of Computer Science, Toronto Canada.
authors.forename: Naum
authors.initials: N
authors.lastname: Papanicolau
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; University of Toronto, Department of Medical Biophysics, Toronto Canada.
authors.forename: Hadi
authors.initials: H
authors.lastname: Tadayyon
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada.
authors.forename: Azza
authors.initials: A
authors.lastname: Al Mahrouki
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada.
authors.forename: Ahmed
authors.initials: A
authors.lastname: El Kaffas
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada.
authors.forename: Alborz
authors.initials: A
authors.lastname: Gorjizadeh
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; University of Toronto, Department of Radiation Oncology, Toronto Canada.
authors.forename: Justin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; University of Toronto, Department of Medical Biophysics, Toronto Canada; University of Toronto, Department of Radiation Oncology, Toronto Canada.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Czarnota
keywords: quantitative ultrasound; radiation therapy; ultrasound; vascular disrupting agents