A radiation monitor and method of monitoring the radiation delivered to a target by a radiation device is described. The radiation monitor contains a set or matrix of pixel ion chambers. The pixel ion chambers are preferably constructed of a top electrode and a segmented electrode connected to the top electrode through a mid layer. The plurality of pixel ion chambers is formed within the mid layer extending from the top electrode to the segmented electrode. The mid layer is laminated to the top electrode and segmented electrode by an array of adhesive dots, wherein the adhesive dots are dimensioned and positioned on the mid layer to provide ventilation slits or channels for the ion chambers.