A system and related method for delivering the anti-tumoral agent carmustine or other types of diagnostic or therapeutic agents into the brain of a patient with a brain tumor includes an insertion device, a skull mount, and a reformulated geometry of the carmustine compound (or other material) optimized for use in the insertion device and for maximized biodegradation time. The insertion device may be front loaded with the carmustine material (or other material) and inserted through the mount on a skull, to the location of the brain tumor, where the carmustine (or other material) is then released. It should be appreciated that the diagnostic and/or therapeutic system and related method thereof are not necessarily limited to the brain of a subject. It may also be used in the organ structures or tubular structures, as well as portions and locations thereof.