Reducing Radiation Exposure to Dental Patients
Radiography is an indispensable tool used in dentistry. It allows for the detection of diseases and other abnormalities, as well as the monitoring of disease progression over time. Nevertheless, ionizing radiation, commonly referred to as X-rays, carries an inherent risk of harm to the patient. The health risks can be classified into two distinct categories of effects as follows:
- Deterministic Effects – these reliably occur above a threshold dose, with their severity increasing alongside the dose. Cataracts, infertility, radiation burns, and radiation-induced lung injury are some examples.
- Stochastic Effects – these result from DNA damage with their probability of occurrence increases with dose, but their severity does not. Teratogenesis, radiation-induced cancer, heart disease, and cognitive decline are some of the examples.
Effective Doses for Dental Imaging
The effective dose for dental imaging varies by a significant margin, depending on the radiographs needed. It’s for this reason why dentists need to pay extra close attention when choosing the right imaging. It is particularly true for children, as they are 32 times more sensitive to radiation risk than adults. Pregnant women should receive dental imaging only when it’s an absolute necessity.
Justification and Optimization
Justification and Optimization are two concepts that all dentists and dental assistants should abide by.
Justification implies that the dentist needs to decide when a radiograph is made to benefit the patient. It means that an initial clinical examination is required to determine the need for diagnostic imaging on some or all tooth-bearing regions. The same principle applies to follow-ups. The frequency will vary depending on the patient’s age, caries history, treatments, oral hygiene, and other similar factors.
Optimization, on the other hand, implies that a radiograph should be of enough diagnostic quality to keep the radiation dose “as low as diagnostically acceptable” (ALADA). This technique will also help reduce exposure to dental office personnel.
Other Means to Minimize Radiation Exposure
Image receptors – For the film, the fastest speed available is F-speed. The film should be processed following the manufacturer’s specifications and by using a safelight. For digital, Complementary metal-oxide-semiconductor (CMOS), Charge Coupled Devices (CCD), and storage phosphor receptors are advisable.
Image viewing – Radiographs should be evaluated in quality assured viewing boxes for film, and monitors for digital, in a darkened environment.
Receptor holders – These need to be used to maximize alignment and minimize repeat exposures.
Exposure time – For intraoral radiographs, 60–70 kVp should be used to optimize contrast and reduce the depth dose. When available, machines with automatic exposure controls should be used. If not possible, technique charts will help minimize under or over-exposure.
Beam collimation – Intraoral radiographs should have a 6 or 7-centimeter beam diameter or smaller and with rectangular collimation, if possible. For other radiographs, the beam should be collimated to the area under investigation.
Hand-held units – Hand-held units should always be used with a shielding ring and held close to the patient’s face.
Patient shielding – Lead aprons and thyroid collars should be used wherever possible.
Cone beam computed tomography – When lower-dose techniques are not sufficient, the smallest field of view applicable should be used. Half-cycle exposures should also be employed wherever possible.
Quality Assurance – Strict protocols should be developed and used for assessing the integrity of x-ray machines, panoramic cassettes, digital image receptors, and darkroom.
Proper Training – Personnel using the X-ray machines should receive the appropriate training, education, and certifications to safely operate these machines. Dental Specialties Institute, Inc. offers three types of training programs approved by the Dental Board of California. These are as follows:
For more information, contact us at (408) 578-2074 or info@dental-specialties.com.