Abstract: Devices and methods for the characterization of areas of radiation in contaminated rooms are provided. One such device is a collimator with a collimator shield for reducing noise when measuring radiation. A position determination system is provided that may be used for obtaining position and orientation information of the detector in the contaminated room. A radiation analysis method is included that is capable of determining the amount of radiation intensity present at known locations within the contaminated room. Also, a visual illustration system is provided that may project images onto the physical objects, which may be walls, of the contaminated room in order to identify the location of radioactive materials for decontamination.