Quantitative ultrasound imaging of therapy response in bladder cancer in vivo

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.

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.

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.

Oncoscience. 2016 Apr 18*** epublish ***

William T Tran, Lakshmanan Sannachi, Naum Papanicolau, Hadi Tadayyon, Azza Al Mahrouki, Ahmed El Kaffas, Alborz Gorjizadeh, Justin Lee, Gregory J Czarnota

Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; Sheffield Hallam University, Centre for Health and Social Care Research, Sheffield UK., Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; University of Toronto, Department of Medical Biophysics, Toronto Canada., Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; Ryerson University, Department of Computer Science, Toronto Canada., Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; University of Toronto, Department of Medical Biophysics, Toronto Canada., Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada., Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada., Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada., Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto Canada; University of Toronto, Department of Radiation Oncology, Toronto Canada., 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.