Monte Carlo Simulation for X-ray Radiation Therapy with Quantum Computer

In the field of bio-health and life science, developing various cancer treatment methods is a topic of significant interest. For the efficient treatment of cancer, one first needs to obtain clear X-ray or MRI images of cancerous areas and then one should be able to precisely target high-energy X-rays or heavy ions at the cancerous area to avoid damaging the nearby healthy cells. Tracing beam trajectory and dose distribution is crucial for the efficient cancer treatment. It is generally agreed that the Monte Carlo method is ideal for this purpose, but it is known to be too slow to obtain the expected dose distribution in due time. Recently, it has been theoretically demonstrated that the Monte Carlo method using a quantum computer (MCQC) has a quantum advantage over the classical Monte Carlo method. Furthermore, MCQC has a sampling advantage over the classical method so that MCQC can produce a reliable result even for complex cases of cancer. In the work, we calculate the beam trajectory and dose distribution by a 6MeV X-ray beam using MCQC and compare the result with the classical one. Finally we will comment on the quantum utility of MCQC for X-ray radiation therapy.