One of the major hurdles for long duration interplanetary space missions is space radiation-induced carcinogenesis. The need for early identification of relevant biomarkers of elevated space radiation risk is crucial for ensuring the health of astronauts after returning from long-duration exploration missions. The longer the duration of the mission the more the risk of space-radiation induced carcinogenesis increases. It is vital to have an accurate understanding of the absorbed dose to sensitive cells comprising the liver and colon cell models for identifying biomarkers that should be further investigated in more human-like systems exposed to space-like radiation. The specific liver and colon cell lines were chosen to build on previous experience with them, to establish a proof of concept for investigation of individual variability impact on biomarkers. Monte Carlo N-Particle transport code 6.2 was used in the simulation of two-dimensional and three-dimensional cell cultures exposed to deuterium-tritium fusion neutrons. Fast neutrons were chosen as most space neutron dose is delivered by neutrons with energy greater than 100MeV. Deuterium-tritium fusion neutrons posses the greatest possible neutron energy outside of large accelerator facilities. Deuterium-tritium neutron-induced charged particles closely resemble the high-LET portion of the GCR spectrum. The absorbed dose was recorded over the cell layer (target volume) using an F6 tally in MCNP. From foil activation analysis, the experimental source strength of 7.65 × 107 neutrons s−1 was used to determine the absorbed dose rate to the cells which ranged from 4.66 to 4.84 mGy h−1. This simulated dose rate will be used to determine the total dose received by the cells in experiments conducted to identify biomarkers related to increased risk of carcinogenesis from fast neutron exposure.