FLASH-RT represents a novel therapeutic radiation modality that holds remarkable potential for mitigating radiation therapy's adverse side effects. This cutting-edge technology allows for sparing healthy tissue while precisely targeting cancerous cells. This is possible by administering an ultra-high-dose-rate in less than a few hundred milliseconds. FLASH-RT has demonstrated impressive results in small-animal models, prompting scientists to adapt and advance existing technologies to make it a viable treatment option for humans. However, producing the ultra-high-dose-rate radiation required for the therapy remains a significant challenge. Several radiation sources, such as very high energy electrons (VHEEs), low energy electrons, x-rays, and protons, have been studied for their ability to deliver the necessary dose. Among them, FLASH-x-ray has gained the most attention owing to its capacity to penetrate deep-seated tumors. Despite the complexity of the process, the potential advantages of FLASH-RT made it an exciting area of research. To achieve the FLASH effect, high-frequency, pulsed irradiated accelerator technology can be employed. Sparing healthy tissue may allow for more aggressive and effective cancer treatments, leading to a better quality of life for patients. Ongoing research and development will be necessary to refine and optimize this approach to radiation therapy.