Effects of registration error on parametric response map analysis: a simulation study using liver CT-perfusion images

17th International Conference on the Use of Computers in Radiation Therapy

物理学;计算机科学

Lausch, A.^1 ; Jensen, N.K.G.^2 ; Chen, J.^3 ; Lee, T.Y.^1 ; Lock, M.^3 ; Wong, E.^1,2

Department of Medical Biophysics, University of Western Ontario, London, ON, N6A 3K7, Canada^1

Department of Physics and Astronomy, University of Western Ontario, London, ON, N6A 3K7, Canada^2

London Regional Cancer Program, London, ON, N6A 4L6, Canada^3

关键词: Functional changes;    Hepatocellular carcinoma;    Misclassification rates;    Misclassifications;    Registration accuracy;    Registration error;    Respiratory motions;    Simulation studies;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/489/1/012032/pdf
DOI  :  10.1088/1742-6596/489/1/012032

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

Purpose: To investigate the effects of registration error (RE) on parametric response map (PRM) analysis of pre and post-radiotherapy (RT) functional images. Methods: Arterial blood flow maps (ABF) were generated from the CT-perfusion scans of 5 patients with hepatocellular carcinoma. ABF values within each patient map were modified to produce seven new ABF maps simulating 7 distinct post-RT functional change scenarios. Ground truth PRMs were generated for each patient by comparing the simulated and original ABF maps. Each simulated ABF map was then deformed by different magnitudes of realistic respiratory motion in order to simulate RE. PRMs were generated for each of the deformed maps and then compared to the ground truth PRMs to produce estimates of RE-induced misclassification. Main findings: The percentage of voxels misclassified as decreasing, no change, and increasing, increased with RE For all patients, increasing RE was observed to increase the number of high post-RT ABF voxels associated with low pre-RT ABF voxels and vice versa. 3 mm of average tumour RE resulted in 18-45% tumour voxel misclassification rates. Conclusions: RE induced misclassification posed challenges for PRM analysis in the liver where registration accuracy tends to be lower. Quantitative understanding of the sensitivity of the PRM method to registration error is required if PRMs are to be used to guide radiation therapy dose painting techniques.