Colleen Bailey1,2, Rachel W Chan1, Jay Detsky3,4, Danny Vesprini3,4, and Angus Z Lau1,2
1Odette Cancer Centre, Sunnybrook Research Institute, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 4Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
1Odette Cancer Centre, Sunnybrook Research Institute, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 4Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
Prostate
cancer patients were scanned at five radiation treatment time points on an MR-Linac.
High b-value imaging revealed visible lesions in 6/8 patients. Significant ADC
increases were observed in 3/8 patients starting at the third treatment time point.
Figure
3 Selected parameter maps with heterogeneous low
ADC region identified as tumour (red arrow). The ADC and IVIM Dt
maps have similar features and become less hypointense at later time points.
The VERDICT intracellular fraction fI is higher in this region and
decreases over time. The data are not always sufficient to fit the R parameter,
particularly outside of the tumour ROI, resulting in dark sections in these
maps.
Figure
4 (a) Summary of parameter values in the tumour
ROI over the course of treatment for one patient. The ADC and Dt
are similar and increase at later treatment time points (* indicates
statistically significant increase over Scan 1). The fp from IVIM
and VERDICT parameters show more variability and do not demonstrate consistent
or statistically significant changes, although the fI trend is
inversely related to the ADC trend. (b) Changes in the ADC throughout treatment for
all eight patients.
