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Integrating dose spatial distribution into radiotoxicity calculation. Ming Zhang Dept. of Bioinformatics & Computational Biology University of Texas M.D. Anderson Cancer Center. Radiotoxicity. Dose volume histogram. Toxicity measured by dose volume (surface) histogram. dose map. DVH.
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Integrating dose spatial distribution into radiotoxicity calculation Ming Zhang Dept. of Bioinformatics & Computational Biology University of Texas M.D. Anderson Cancer Center
Dose volume histogram Toxicity measured by dose volume (surface) histogram dose map DVH volume dose (Gy)
Dose spatial distribution Dose levels and spatial distribution both affect toxicity
Maximum clusters local damage function: dose received at a voxel probability that the voxel is damaged
Cluster of damaged voxels Clusters: connected components of damaged voxels cluster size = 1, 1, 1, 1, 1 cluster size = 1, 3 maximum cluster
Connectivity 1-connectivity 2-connectivity
Maximum clusters dose map local damage probability maximum cluster size maximum cluster location 2648.91
maximum clusters rendering
DSH (absolute area)
DSH (relative area)
difference of maximum clusters
Discussions • Maximum clusters describe radiotoxicity by • Incorporating dose spatial distribution into cluster calculation • Working with all dose levels simultaneously • Providing a visualization tool to select treatment plans (location and size of maximum cluster)
Discussions • Local damage function • sigmoidal shape: analytical, piecewise • parameters (patient/organ specific) • Computational complexity • number of iterations in simulation • all possible parameter combinations
Dose component histogram For each dose level d DVH: sum of all voxels receiving dose d or more DCH: largest component of organ region receiving dose d or more
Cluster/component connectivity • Local connectivity (immediate neighborhood) • 1-connectivity • 2-connectivity • n-connectivity • Regional connectivity (extended neighborhood)
Conclusions • Dose spatial distribution should be integrated into radiotoxicity calculation • Connectivity determines cluster/component formation • Maximum cluster • works with all dose levels simultaneously • provides size and location of MC (rendering) • Dose component histogram (DCH) • Incorporates spatial distribution into DVH
Collaborators: Howard Thames, Ph.D. (MDACC) Susan Tucker, Ph.D. (MDACC) Radhe Mohan, Ph.D. (MDACC) Lei Dong, Ph.D. (MDACC) Xiaodong Zhang, Ph.D. (MDACC) Ronald Goldman, Ph.D. (Rice) Falai Chen, Ph.D. (USTC, China) Ming Zhang, Ph.D. Department of Bioinformatics & Computational Biology UT M.D. Anderson Cancer Center mzhang@mdanderson.org