Flash Radiation Therapy: Current Insights and Future Prospects

FLASH radiotherapy (RT) is an innovative approach used in cancer treatment. The FLASH effect is observed at ultra-high dose rates (UHDR) of approximately 40 Gy/s or higher. This treatment method has the potential to effectively destroy tumor cells while causing less damage to healthy tissues. It has been shown that FLASH irradiation reduces the severity of toxicity in normal tissues compared to conventional dose rate (CONV) irradiation that is currently being utilized in clinical settings. The shortened treatment durations characteristic of FLASH-RT, typically falling below 0.1 seconds, offer the distinct advantage of minimizing uncertainties associated with treatment application arising from intra-fractional motion. This book chapter covers the types of radiation used in FLASH RT, the biological effects of these radiation types, promising FLASH RT technologies, and dosimetry. The types of energy used in FLASH RT are generally similar to those used in CONV RT, but they are applied at much higher dose rates. FLASH RT requires special technology to deliver radiation at high dose rates. These technologies include Linear Accelerators (LINAC), Proton Accelerators and Carbon Ion Accelerators. The main types of energy that can be used in FLASH RT are Electrons, Protons, X-rays, and Carbon ions. Currently, studies aiming to use electrons, protons and X-rays in UHDR transmission methods are ongoing. Among these studies are those that focus on the use of 100-200 MeV very high energy electrons (VHEE) to target deep-located tumors with FLASH RT using electrons. There are also studies on proton FLASH RT, which aim to take advantage of the physical properties of protons called Bragg peaks. This book chapter on FLASH RT covers promising FLASH RT technologies, FLASH radiobiology, patient treatments with FLASH RT, and radiation dosimetry of FLASH RT. FLASH RT is considered a revolutionary innovation in cancer treatment. Advances in technological and biological research indicate that this treatment method could lead to wider clinical applications.