What is the purpose of the unit Roentgen (R)?

The unit Roentgen (R) is specifically designed to measure x-ray exposure in air. It quantifies the amount of ionization produced in air by x-rays or gamma rays, providing a direct indicator of radiation exposure levels in a given environment. This measurement is vital in radiological safety and dosimetry, as it helps ensure that exposure levels remain within safe limits for both patients and healthcare workers.

While dose equivalent in humans is measured using other units such as Sieverts, and energy or quality of x-ray beams is expressed through different metrics, the primary purpose of the Roentgen remains focused on measuring the ionizing radiation exposure in air, making it a crucial concept in radiation protection and medical imaging practices.