10269-ET-10 ARRAYS FOR DELIVERING TUMOR TREATING FIELDS (TTFIELDS) TO THE MOUSE HEAD

Abstract

Abstract INTRODUCTION Tumor Treating Fields (TTFields) therapy is an approved treatment for glioblastoma (GBM), the most common malignant brain tumor. TTFields therapy is delivered continuously by two pairs of arrays placed orthogonally on the skin surrounding the tumor region. Investigational in vivo work in the field of GBM currently utilizes mouse models. To expand the possibility for TTFields-GBM in vivo studies, TTFields arrays for the mouse head are needed. The small dimensions and specific geometries of the mouse head make the development of such arrays challenging. METHODS We tested a variety of layouts for the arrays to identify one that will be suited to the geometries of the mouse head, and that will minimally restrict head movement. Efficient treatment delivery requires good adherence to the skin; hence, we investigated different skin attachment adhesive tapes. To validate the ability of the selected arrays to deliver therapeutic field intensity to the desired region, we performed direct fields measurements and simulations. RESULTS We employed 2 strategies to overcome the small size and confining geometries of the mouse head: (1) only two of the four arrays were situated on the head – opposing arrays were placed on the mouse torso; (2) the arrays on the head were each divided into two small disks instead of just one large disk. We identified an adhesive tape for securing the arrays to the skin that was thin and transparent, facilitating correct positioning of the arrays on the mouse head. The tape also offered good tackiness, and allowed for easy removal without leaving residual adhesive on the skin, facilitating repeated array placement. The arrays met the requirements for efficient treatment: field intensity ≥ 1 V/cm RMS, current ≥ 50 mA, usage ≥ 75%. CONCLUSIONS We were able to develop flexible mouse head arrays, that adheres strongly to the skin, enabling efficient electric field delivery with minimal animal discomfort. These arrays provide means to expand TTFields-GBM treatment research, and will contribute to advance this field.