Comparison of the Medical Uses and Cellular Effects of High and Low Linear Energy Transfer Radiation

Abstract

Exposure to ionizing radiation can occur during medical treatments, from naturally occurring sources in the environment, or as the result of a nuclear accident or thermonuclear war. The severity of cellular damage from ionizing radiation exposure is dependent upon a number of factors including the absorbed radiation dose of the exposure (energy absorbed per unit mass of the exposure), dose rate, area and volume of tissue exposed, type of radiation (e.g., X-rays, high-energy gamma rays, protons, or neutrons) and linear energy transfer. While the dose, the dose rate, and dose distribution in tissue are aspects of a radiation exposure that can be varied experimentally or in medical treatments, the LET and eV are inherent characteristics of the type of radiation. High-LET radiation deposits a higher concentration of energy in a shorter distance when traversing tissue compared with low-LET radiation. The different biological effects of high and low LET with similar energies have been documented in vivo in animal models and in cultured cells. High-LET results in intense macromolecular damage and more cell death. Findings indicate that while both low- and high-LET radiation activate non-homologous end-joining DNA repair activity, efficient repair of high-LET radiation requires the homologous recombination repair pathway. Low- and high-LET radiation activate p53 transcription factor activity in most cells, but high LET activates NF-kB transcription factor at lower radiation doses than low-LET radiation. Here we review the development, uses, and current understanding of the cellular effects of low- and high-LET radiation exposure.

Iron Deposition in the Bone Marrow and Spleen of Nonhuman Primates with Acute Radiation Syndrome

“…There is currently an increasing concern worldwide regarding potential radiation exposures, whether from clinical uses of radiation, nuclear accidents, or military/terrorist events, emphasizing the need for radiation countermeasure development (39)(40)(41)(42). Importantly, the development of effective countermeasures requires a complete understanding of the mechanisms of radiation-induced sequelae (17,(39)(40)(41)(42).…”

“…There is currently an increasing concern worldwide regarding potential radiation exposures, whether from clinical uses of radiation, nuclear accidents, or military/terrorist events, emphasizing the need for radiation countermeasure development (39)(40)(41)(42). Importantly, the development of effective countermeasures requires a complete understanding of the mechanisms of radiation-induced sequelae (17,(39)(40)(41)(42). Although the immediate effects of ionizing radiation exposure are believed to be due to direct effects on cells and oxygen and nitrogen radical generation, the mechanism(s) of development of late effects after radiation exposure are not completely understood.…”

A spatial measure-valued model for radiation-induced DNA damage kinetics and repair under protracted irradiation condition

“…For the biological interpretation of the above kernels, besides the already known clustered effect of DNA lesions, there is experimental evidence that the repair rate of DNA lesions created by densely ionizing radiation, such as LET, is different from the repair of lesions induced by sparsely ionizing radiation, such as X-rays (Russ et al. 2022 ; Guerra Liberal et al. 2023 ).…”

Pulsed Electromagnetic Fields (PEMFs) Trigger Cell Death and Senescence in Cancer Cells

“…Chemotherapy, radiation therapy [ 3 ], radionuclide therapy [ 4 ], immunotherapy and hormone therapies along with surgery are traditionally applied, solely or in combination, and are considered as powerful tools in our arsenal against cancer. As far as radiation therapy is concerned, ionizing irradiation [characterized by very low wavelength, high frequency and low linear energy transmission (LET)] [ 5 ] is conventionally utilized as the treatment of choice, resulting in the shrinkage or remission of tumors [ 6 ]. However, following this intervention, serious side effects usually occur at the local and systematic level, e.g., secondary cancer, Radiation-Induced Coronary Artery Disease (RICAD) [ 7 ], etc.…”