Automatic Patient Modeling for Hyperthermia Treatment Planning of Head and Neck Cancer

Head and neck (H&N) cancer is the term used to describe a wide range of malig- nant tumors originating in the upper airways and swallowing tracts. In 2012, this disease accounted for approximately 5% of all cancers worldwide, with 680,000 new cases diagnosed and 370,000 recorded deaths, resulting as the seventh most common cancer worldwide. The H&N region is often divided in subregions containing dfferent tumor sites, as depicted in Figure 1.1: the oral cavity, paranasal sinus and nasal cavity, salivary glands, nasopharynx, oropharynx, hypopharynx (bot- tom part of the throat) and larynx. Tumors in the eyes, brain and skin are generally not considered H&N cancer

Feasibility and relevance of discrete vasculature modeling in routine hyperthermia treatment planning

Purpose: To investigate the effect of patient specific vessel cooling on head and neck hyperthermia treatment planning (HTP). Methods and materials: Twelve patients undergoing radiotherapy were scanned using computed tomography (CT), magnetic resonance imaging (MRI) and contrast enhanced MR angiography (CEMRA). 3D patient models were constructed using the CT and MRI data. The arterial vessel tree was constructed from the MRA images using the ‘graph-cut’ method, combining information from Frangi vesselness filtering and region growing, and the results were validated against manually placed markers in/outside the vessels. Patient specific HTP was performed and the change in thermal distribution prediction caused by arterial cooling was evaluated by adding discrete vasculature (DIVA) modeling to the Pennes bioheat equation (PBHE). Results: Inclusion of arterial cooling showed a relevant impact, i.e., DIVA modeling predicts a decreased treatment quality by on average 0.19 °C (T90), 0.32 °C (T50) and 0.35 °C (T20) that is robust against variations in the inflow blood rate (|ΔT| 0.5 °C) were observed. Conclusion: Addition of patient-specific DIVA into the thermal modeling can significantly change predicted treatment quality. In cases where clinically detectable vessels pass the heated region, we advise to perform DIVA modeling