MARS spectral CT is an up and coming imaging modality which shows great promise in revealing unique diagnostic information and industrial analysis techniques. Because this imaging modality based on X-ray CT, it is of utmost importance to study the radiation dose aspects of its use. Moreover, the capabilities of spectral imaging show potential for a new method in 3D dosimetry, one which is personalized. This thesis reports on the use of Monte Carlo simulation tool TOPAS in estimating the dose to a sample scanned with the pre-clinical MARS scanner, and the results are experimentally verified using an ion chamber and TLDs. Use of EPDs in characterizing radiation within the gantry was also investigated. In addition, a pilot study was conducted into a potential algorithm a future onboard personalized dosimetry system may utilize. On the whole, all dosimetry techniques indicate a MARS scan dose on the order of 20 mGy.