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PURPOSE/OBJECTIVE(S) Tumor Treating Fields (TTFields) are alternating electric fields that inhibit mitosis of cancer cells. In the clinic, TTFields are delivered via transducer arrays placed on the skin of the patient in close proximity to the tumor. A recent study has shown a connection between survival of newly diagnosed Glioblastoma (ndGBM) patients and dose delivered to the tumor bed [1]. In this case, TTFields dose was defined as the product of the power density delivered by the field and device usage (% of time patient was on active treatment). Thus, a key to enhancing the efficacy of TTFields dose is to maximize dose delivery to the tumor by controlling three factors. (a) Designing the transducer arrays to maximize the field intensity delivered by the arrays, (b) Planning the placement of the arrays on the skin to maximize field delivery to the tumor (c) designing the device to increase usage (% of time patient is on active treatment). Here we present ongoing research developing new methods for improving dose delivered to the tumor utilizing the three factors mentioned above. MATERIALS/METHODS Realistic computational head models of Glioblastoma patients were created using a previously described method [1]. Virtual transducer arrays of different shapes and sizes were placed on the models, and the delivery of TTFields were numerically simulated. The average power density within the brain and tumor bed delivered by each type of transducer array were calculated. An optimization algorithm designed to place the transducer arrays on the scalp in a manner that maximizes power density delivered to the tumor bed was devised. The algorithm utilized numerical simulation of TTFields delivery in an iterative manner. RESULTS Generally speaking, transducer arrays with larger surface area delivered higher average power density to the entire brain and tumor bed. However, in some cases, the size of the arrays positioning the arrays on the head in a manner that maximized power density delivery to the tumor. For some type of arrays, the optimization algorithm yielded layouts that increased power delivered to the tumor bed by over 30% relative to a "standard" central layout. CONCLUSION We have demonstrated how array design and optimization algorithms can be used to enhance TTFields dose at the tumor. Optimizing array shape and using light-weight thin materials for the construction of the arrays could yield arrays that not only deliver higher doses to the tumor bed, but also enhance patient comfort during treatment, thereby leading to an increase in usage. |
