Linear Energy Transfer (LET) quantifies how much energy a radiation particle transfers to the material it passes through per unit of distance. This measurement is critical in radiation therapy and radiobiology because it helps determine the effectiveness of different types of radiation in causing biological damage.
The appropriate unit for LET is keV/micrometer, reflecting the energy transferred (in kilo-electronvolts, keV) over a specific distance (in micrometers). This unit allows clinicians and researchers to evaluate and compare the potential biological effects of varying types of radiation, such as alpha particles, beta particles, or gamma rays. Higher LET values correspond to more significant energy deposition and, therefore, a greater likelihood of inducing biological damage, such as DNA breaks.
The other options refer to measurements that do not accurately capture the concept of LET. For example, J/Kg and J/KeV are not directly related to the concept of energy transfer over distance in the context of radiation. Similarly, C/Kg relates to the measurement of ionization, not directly to energy deposition per unit distance, which is fundamental to understanding LET. Thus, keV/micrometer is the correct unit for measuring Linear Energy Transfer.