Radiation protection of patients

Patients are exposed to ionizing radiation when they undergo diagnostic examinations using x-rays or radiopharmaceuticals. Radiation emitted by radioisotopes or radiation generators is utilized in therapy for cancer or benign lesions and also in interventional procedures using fluoroscopy.

International Atomic Energy Agency

The International Atomic Energy Agency (IAEA) has established a program on radiological protection of patients in recognition of the increasing importance of this topic. The emphasis in the past had been on radiation protection of staff and this has helped to reduce radiation doses to staff at levels well below the limits prescribed by the International Commission on Radiological Protection (ICRP) and accepted by most countries. The recent emphasis on radiation protection of patients is helping in developing strategies to reduce radiation doses to patients without compromising on diagnostic or therapeutic purpose.^[1]

ALARA

"ALARA" ("As Low As Reasonably Achievable") should be maintained to reduce radiation doses to staff as well as patients.^[2]

Lead shielding during routine X-rays and CT scans

A mock dental X-ray being performed. The "patient" (a stuffed toy) is wearing a lead apron with collar to protect the thyroid and body from radiation exposure. Lead aprons are no longer recommended for dental X-rays.^[3]

X-ray of the spine with a gonadal shield in place. Use of the gonadal shield is no longer recommended as it results in more radiation being used to produce the image, and does not protect against internal scatter.

Starting in the 1950s, lead shielding began to be used on patients during all X-rays over the abdomen to protect the gonads (reproductive organs) or a fetus if the patient was pregnant. Dental X-rays would also typically additionally use lead shielding to protect the thyroid. However, a consensus was reached between 2019^[4][5][3] and 2021^[6][7] that lead shielding for routine diagnostic X-rays is not necessary and may in some cases be harmful. In part, this is due to improved understanding of the effects of radiation on patients, as the amount of radiation patients were exposed to in routine X-rays and CT scans was found to not affect fertility or a developing pregnancy. It was also due to the improvement of X-ray machines. For instance, older X-ray machines would use a set amount of radiation, and used film which requires more X-rays.^[3] Modern X-ray machines are digital, and automatically use the minimum amount of radiation needed to image the patient, which means overall the radiation levels are much lower than in the past; however, if the lead shield is in the field being imaged, the machine will produce more X-rays in order to attempt to penetrate the lead shield. Additionally, if the shield is in the field, this may affect the image produced, requiring a second X-ray to be performed, which would also lead to overall increased radiation exposure. Additionally, patient shielding is ineffective at reducing internal scatter; because only a portion of the patient is shielded, X-rays may still go through the gonads or fetus from bouncing off the imaged areas internally.^[8]

Lead shielding is still recommended for other people in the room, such as family members, health professionals, and X-ray technicians, as it reduces the amount of radiation received. Unlike with patients, there's no risk of increased radiation from using shielding since the use of shielding does not increase the amount of X-rays being produced by the machine as there is no potential for it to accidentally end up in the field. Additionally, health care professionals may be performing many X-rays a day, meaning they are exposed to more cumulative radiation, unlike patients who typically receive far fewer.^[2]

See also

• Journal of Radiological Protection
• International Radiation Protection Association
• European Committee on Radiation Risk