Graded-threshold parametric response maps: towards a strategy for adaptive dose painting

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

物理学;计算机科学

Lausch, A.^1 ; Jensen, N.^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: Confidence interval;    Disconnected clusters;    Functional imaging;    Hepatocellular carcinoma;    Heterogeneous clusters;    Intensity-modulated radiotherapy;    Treatment outcomes;    Treatment response;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/489/1/012031/pdf
DOI  :  10.1088/1742-6596/489/1/012031

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

Purpose: To modify the single-threshold parametric response map (ST-PRM) method for predicting treatment outcomes in order to facilitate its use for guidance of adaptive dose painting in intensity-modulated radiotherapy. Methods: Multiple graded thresholds were used to extend the ST-PRM method (Nat. Med. 2009;15(5):572-576) such that the full functional change distribution within tumours could be represented with respect to multiple confidence interval estimates for functional changes in similar healthy tissue. The ST-PRM and graded-threshold PRM (GT-PRM) methods were applied to functional imaging scans of 5 patients treated for hepatocellular carcinoma. Pre and post-radiotherapy arterial blood flow maps (ABF) were generated from CT-perfusion scans of each patient. ABF maps were rigidly registered based on aligning tumour centres of mass. ST-PRM and GT-PRM analyses were then performed on overlapping tumour regions within the registered ABF maps. Main findings: The ST-PRMs contained many disconnected clusters of voxels classified as having a significant change in function. While this may be useful to predict treatment response, it may pose challenges for identifying boost volumes or for informing dose-painting by numbers strategies. The GT-PRMs included all of the same information as ST-PRMs but also visualized the full tumour functional change distribution. Heterogeneous clusters in the ST-PRMs often became more connected in the GT-PRMs by voxels with similar functional changes. Conclusions: GT-PRMs provided additional information which helped to visualize relationships between significant functional changes identified by ST-PRMs. This may enhance ST-PRM utility for guiding adaptive dose painting.