Dose cluster model parameterization of the parotid gland in irradiation of head and neck cancer

AbstractTo explore the parotid normal tissue complication probability (NTCP) modeling with percolation-based dose clusters for head-and-neck patients receiving concomitant chemotherapy and radiation therapy. Cluster models incorporating the spatial dose distribution in the parotid gland were developed to evaluate the radiation induced complication. Cluster metrics including the mean cluster size (NMCS) and the largest cluster size both normalized by the gland volume (NSLC) were evaluated and scrutinized against the benchmark NTCP. Two fitting strategies to the Lyman –Kutcher–Burman (LKB) model using the maximum likelihood method were devised: the volume parametern fixed at 1.0 (mean dose model) and unrestricted (full LKB model). The fitted parametersTD50 andm were assessed with the LKB NTCP models with the available xerostomia data. NSLC was a better metric than NMCS with reference to the LKB model and strong correlation (r  ~ 0.95) was observed between NTCP and NSLC. The mean dose model returned the parameterTD50 (39.9  Gy) andm (0.4) from the NSLC of threshold dose at around 40  Gy. Drastically differentTD50 andm values were obtained from the fittings via the full LKB model, where the threshold dose would be near 27  Gy. Bootstrapping analyses further confirmed the fitting outcomes. Strong correlation with the traditional NTCP models revealed that the cluster model could achieve what NTCP models attain and may offer additional information. Parameterization of the...
Source: Australasian Physical and Engineering Sciences in Medicine - Category: Biomedical Engineering Source Type: research