Radiation Dosimetry

Committed to the ALARA Principle
"As Low As Reasonably Achievable"

Dosimetry charts are found below. Please review a helpful document to get you started by clicking here.


C-Dental and McCormack Dental Imaging centers are completely digital. There is a significant reduction in radiation for full mouth X-rays. Additionally, our Cone Beam CT scanner, the NewTom VGi, offers various scan settings that are selected based on the diagnostic survey ordered by your doctor.


Dental X-ray examinations provide valuable information that helps your doctor evaluate your oral health. With the help of radiographs (the term for pictures taken with X-rays), your doctor can look at what is happening beneath the surface of your teeth and gums. If you have questions about your dental X-ray exam, talk with your doctor.


How do dental X-rays work?


As X-rays pass through your mouth they are mostly absorbed by teeth and bone because these tissues, which are called hard tissues, are denser than cheeks and gums, which are called soft tissues. When X-rays strike the film or a digital sensor, an image called a radiograph is created. Radiographs allow your dentist to see hidden abnormalities, like tooth decay, infections and signs of gum disease, including changes in the bone and ligaments holding teeth in place.


Why are dental X-rays important?


Because many diseases of the teeth and surrounding tissues cannot be seen when your dentist examines your mouth, an X-ray examination can help reveal:

  • Small areas of decay between the teeth or below existing restorations (fillings)

  • Infections in the bone

  • Periodontal (gum) disease

  • Abscesses or cysts

  • Developmental abnormalities

  • Some types of tumors

Finding and treating dental problems at an early stage can save time, money and unnecessary discomfort. Radiographs can help your doctor detect problems in your mouth that otherwise would not be seen.


How do dental X-rays compare to other sources of radiation?


The amount of radiation that we are exposed to from dental X-rays is very small compared to our daily exposure from things like, cosmic radiation and naturally-occurring radioactive elements (for example, those producing radon).


The table below compares our estimated exposure to radiation from dental X-ray with other various sources. As indicated below, a microsievert is a unit of measure that allows for some comparison between radiation sources that expose the entire body (such as natural background radiation) and those that only expose a portion of the body (such as X-rays).


What are Microsieverts (μSv)?


The sievert (Sv) is the SI (International System of Units) unit of measurement that represents the biological effects of ionizing radiation. 1 sievert equals 1 million microsieverts (μSv).

CBCT Dosimetry C-Dental NewTom VGi Dosimetry Study© (2015) copyright pending 

Depending on the survey ordered by your doctor, C-Dental X-ray technologists will select from the field of view and resolution settings seen in the chart below. This selection is made based on the ordered survey's requirements for anatomy and image quality. C-Dental will always choose scan settings to keep radiation dosage as low as reasonably achieveable while maintaining the diagnostic expectations of the referring doctor. The effective dose each patient receives is unique based on their size and positioning. The figures below represent the average effective dose as determined by a dosimetry phantom.

A 20% variable in dosimetry exists in all fields of view and resolution settings. 3 factors apply:

  • Patient position within the primary X-Ray beam

  • Size of patient’s head in comparison to the child or adult dosimetry phantom

  • Relative position of the patient to the dosimetry phantom during the study


2D Digital X-Ray

Other Sources of Radiation

2D Dental X-rays

Digital FMX

Digital Panograph

Digital Lateral Ceph

Digital PA Ceph

Film 2D TMJ Survey

μsv (microsieverts) Average Effective Dose






Dosimetry figures were obtained using a tissue equivalent dosimetry phantom. Each level contains dosimetry microchips that represent a patient's anatomy.

Medical CT Imaging






Coronary angiography


2D Medical Imaging


Chest (Lateral Study)


Cervical Spine




Natural Sources of Radiation Average Annual Dose



Cosmic Exposure

Terrestrial Exposure



μsv (microsieverts) Average Effective Dose





















mrem (millirem)







"2015 NewTom VGi Dosimetry Study" 2015 John B. Ludlow, Jerome N. Peck


The American Dental Association website http://www.ada.org


“Patient Risk Related to Common Dental Radiographic Examinations : The Impact of 2007 International Commission on JADA” 2008;139(9):1237-1243 Stuart C. White John B. Ludlow, Laura E. Davies-Ludlow and Regarding Dose Calculation Radiological Protection Recommendations


National Council on Radiation Protection and Measurements. NCRP Report No. 160, Ionizing Radiation Exposure of the Population of the United States. http://ncrponline.org/publications/reports/ncrp-report-160/


"Effective doses in radiology and diagnostic nuclear medicine: a catalog" 2008 Mettler FA Jr, Huda W, Yoshizumi TT, Mahesh M. http://pubs.rsna.org/doi/10.1148/radiol.2481071451?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed&