This invention provides a method for detecting cancer cells in a sample comprising detection of the expression of a Prostate Tumor Inducing Gene in the sample, wherein a positive detection of the expression indicates the presence of cancer cells in the sample. This problem has been overcome by preceding the epitaxial deposition of N silicon onto the P substrate with an additional process step in which a buried N layer is formed at the surface of the substrate by ion implantation. The decontamination unit may be ruggedized for use in hostile environments such as those that may be anticipated for military applications. The majority of the tumor can be surgically removed prior to insertion of the neutron emitting source.