Radiation Dose



Radiation Dose

Introduction

The study is related to the exposure creep trends of radiation dose. The main characteristic of the interaction of ionizing radiation and the environment is an ionization effect. In the initial period of development of radiation dosimetry often had to deal with X-rays that were distributed in the air. Therefore, as a quantitative measure of the radiation field used in the degree of ionization of the air X-ray tubes or machines. A quantitative measure based on the value of the ionization of dry air at normal atmospheric pressure which is relatively easy to measure and is called the exposure dose (Diiulio 2010).

The exposure dose determines the ability of ionizing x-ray and gamma-ray energy and expresses the radiation converted to kinetic energy of charged particles per unit mass of air. An exposure creep trend of radiation dose is the ratio of the total charge of all ions of one sign in the elementary volume of air to the mass of air in this volume.

Discussion

For exposure creep trends of radiation dose, various units of measurement are used to quantify radiation activity that is how much a radiation source emits, radiation exposure that is how much radiation is absorbed from the radiation source, and other factors related to radiation (sciencealert.com).

The strength of the source of radiation is measured by becquerel [Bq]; 1 becquerel = 1 event of radiation emission per second.

Radiation energy is measured by electronvolt (eV), kiloelectron (keV), megaelectronvolt (MeV), joule, and watt.

Radiation exposure is measured by radiation equivalent man (rem) and sievert (Sv); 1 Sv = 100 rem .

Radiation dose is measured in units of gray (Gy) and radiation absorbed dose (rad); 1Gy = 100 rads.

In the United States, the currently allowed annual occupational radiation exposure is limited to 5,000 millirem (5 rem), because a fetus is more sensitive to radiation than children or adults, state and federal laws in the U.S. limit the radiation dose of pregnant workers to 500 millirem (0.5 rem).

An important strategy for maintaining radiation safety is to avoid the unnecessary use of diagnostic tests that incorporate radiation, although this can be challenging because diagnostic imaging and interventional radiology procedures are increasingly used to evaluate a wide range of illnesses and injuries. Inappropriate use of such technologies can lead to unnecessary exposure to radiation (Gibson et al. 2012).

The use of computerized tomography (CT) is increasing rapidly in the U.S. and other countries, which increases the level of radiation exposure in persons undergoing CT. The advent of positron emission tomography (PET)-CT and fluoroscopy-assisted CT further increases the potential for CT-related radiation exposure.

In 1989, CT scanning represented approximately 2% of all radiologic procedures performed, and 20% of the overall cause of radiation exposure in the United Kingdom. By 1998, these values increased to 4% and 40%, respectively.

In 2000, CT scanning represented 11% of all radiologic procedures and almost 70% of the overall cause of radiation exposure among persons in the U.S.

CT scanning involves significantly higher radiation exposure than X-ray. A chest CT scan, for example, involves ...