Radiologic and nuclear medicine studies in the United States and worldwide: frequency, radiation dose, and comparison with other radiation sources--1950-2007.

The U.S. National Council on Radiation Protection and Measurements and United Nations Scientific Committee on Effects of Atomic Radiation each conducted respective assessments of all radiation sources in the United States and worldwide. The goal of this article is to summarize and combine the results of these two publicly available surveys and to compare the results with historical information. In the United States in 2006, about 377 million diagnostic and interventional radiologic examinations and 18 million nuclear medicine examinations were performed. The United States accounts for about 12% of radiologic procedures and about one-half of nuclear medicine procedures performed worldwide. In the United States, the frequency of diagnostic radiologic examinations has increased almost 10-fold (1950-2006). The U.S. per-capita annual effective dose from medical procedures has increased about sixfold (0.5 mSv [1980] to 3.0 mSv [2006]). Worldwide estimates for 2000-2007 indicate that 3.6 billion medical procedures with ionizing radiation (3.1 billion diagnostic radiologic, 0.5 billion dental, and 37 million nuclear medicine examinations) are performed annually. Worldwide, the average annual per-capita effective dose from medicine (about 0.6 mSv of the total 3.0 mSv received from all sources) has approximately doubled in the past 10-15 years.

Nuclear medicine exposure in the United States, 2005-2007: preliminary results.

Medical radiation exposure of the U.S. population has not been systematically evaluated for almost 25 years. In 1982, the per-capita dose was estimated to be 0.54 mSv and the collective dose 124,000 person-Sv. The preliminary estimates of the National Council on Radiation Protection and Measurements Scientific Committee 6-2 medical subgroup are that, in 2006, the per-capita dose from all medical exposure (not including radiotherapy) had increased almost 600% to 3.0 mSv and the collective dose had increased more than 700% to approximately 900,000 person-Sv. >Nuclear medicine accounted for only about 2% of all procedures but 26% of the total collective dose from diagnostic studies in medicine. In 1982, the estimated number of nuclear medicine procedures was about 7.5 million. The per-capita effective dose from nuclear medicine was 0.14 mSv and the collective dose was 32,000 person Sv. By 2005, the estimated number of procedures had increased to about 19.6 million. The per-caput effective dose increased to about 0.75 mSv and the collective dose to about 220,000 person Sv. There also has been a marked shift in the type of procedures being performed with cardiac scanning accounting for about 70% of procedures.

Radiological terrorism.

A radiological terrorist attack on the United States is a possibility. This could involve the dispersal of radioactive material by an attack on a nuclear facility, deployment of a radiation dispersal device, or, less likely, detonation of a nuclear weapon. To decrease our vulnerability to this type of threat, the medical community should have a basic understanding of radiation hazards and their medical management, and it should be prepared to interact with appropriate federal agencies to facilitate the employment of emergency response plans.

Exposure reduction through quality assurance for diagnostic x-ray procedures.

Traditional state x-ray inspection programs concentrate on measurement of x-ray machine parameters such as kVp and mAs, timer accuracy, collimation, etc. In 1996, the New Jersey radiation control program began a paradigm shift from the traditional inspection to an outcome-based inspection that concentrated on two indicators of performance: image quality and entrance skin exposure (ESE). Through extensive outreach and involvement of stakeholders, a new approach was designed that placed an emphasis on quality assurance. Key to the positive outcome has been the credentialing of medical physicists. On 16 January 2001, the final regulation titled "Quality Assurance Programs for Medical Diagnostic X-ray Installations" was adopted. The new regulations require that each facility using diagnostic medical x-ray equipment (including radiographic, fluoroscopic, x-ray bone densitometric, and computed tomographic) establish and carry out a quality assurance program. The new regulation specifies the quality control tests, frequencies, and standards that are part of the quality assurance program. Five years of data have been gathered. Both ESE and image quality are checked and the inspectors conduct an audit of the facility's quality assurance program. ESE has been decreased by 34% for lumbar spine, 46% for chest, and 66% for foot x-ray procedures. Image quality has improved by 22%. Quality improvement initiatives were extended to the larger dental x-ray community. Through outreach and information sharing, stakeholders were instructed in the factors that affect patient radiation exposure and image quality and were encouraged to take actions to improve in these areas.

Medical radiation exposure in the U.S. in 2006: preliminary results.

Medical radiation exposure of the U.S. population has not been systematically evaluated for almost 25 y. In 1982, the per capita dose was estimated to be 0.54 mSv and the collective dose 124,000 person-Sv. The preliminary estimates of the NCRP Scientific Committee 6-2 medical subgroup are that, in 2006, the per capita dose from medical exposure (not including dental or radiotherapy) had increased almost 600% to about 3.0 mSv and the collective dose had increased over 700% to about 900,000 person-Sv. The largest contributions and increases have come primarily from CT scanning and nuclear medicine. The 62 million CT procedures accounted for 15% of the total number procedures (excluding dental) and over half of the collective dose. Nuclear medicine accounted for about 4% of all procedures but 26% of the total collective dose. Medical radiation exposure is now approximately equal to natural background radiation.