This category covers
dose and risk from diagnostic x-rays, fluoroscopy and CT scans, dental x-rays, radiation therapy procedures, etc.
Worried about x rays? Watch this video.
Pregnant and worried about x rays? Watch this video.
The risks of health effects from radiation doses received during diagnostic imaging procedures are either too small to be observed or are nonexistent. The benefits from properly performed clinically indicated diagnostic imaging procedures, including CT scans, far outweigh any hypothetical cancer risk. Diagnostic medical imaging procedures provide a medical benefit to you even if they do not appear to reveal anything and are of less risk than their alternatives, such as exploratory surgery.
Even if the result of the imaging exam was negative, the physicians were provided information they could use to determine the next course of action. Refusing medical imaging procedures may result in real and substantial risk by not receiving the clinical benefits of the procedures.
Because the Health Physics Society recommends against quantitative estimates of health risks for radiation doses below 100 mSv, we will not calculate hypothetical risks for diagnostic imaging procedures. The Society's position statement "Radiation Risk in Perspective" explains in more detail why it is inappropriate to estimate health risks at these doses. Some risk information is available from www.radiationanswers.org.
If you want to know the specific dose you or a family member may have received for a particular exam you underwent, you need to contact your health care provider and ask for the effective dose due to the procedures. Typical doses from many diagnostic imaging procedures are posted on our website.
The following health physics questions have been answered by an expert and approved by our editors for inclusion in our "Ask the Experts" feature. Click on the question to see the answer.
| Questions in this Category Are in the Following Subcategories: |
| • Diagnostic X Ray and CT |
| • Dental |
| • MRI |
| • Therapy - Radiation Oncology |
| • Therapy - Nuclear Medicine |
| • Worker Issues |
| • Pediatric Issues |
| • Miscellaneous |
| |
| Diagnostic X Ray and CT |
| Q7532 |
– |
Concern about CT heart scans |
| Q10494 |
– |
Compare effective doses from medical procedures to natural background |
| Q10540 |
– |
How does CT scan dose in mGy relate to dose in mSv? |
| Q10543 |
– |
Many x rays |
| Q10549 |
– |
Radiation exposure while waiting for procedure |
| Q10578 |
– |
Radiation dose from HSG tests |
| Q10610 |
– |
Radiation exposure from multiple procedures including MRI, CT, and ultrasound |
| Q10613 |
– |
Effects from many CT scans and alternatives |
| Q10723 |
– |
Can a CT scan cause male infertility or genetic problems? |
| Q10788 |
– |
Effects of a single exposure compared to prolonged exposure |
| Q10866 |
– |
Could a series of x rays cause a burning sensation of the skin? |
| Q11089 |
– |
How does patient size affect radiation dose? |
| Q11112 |
– |
Was radiation dermatitis caused by a portable chest x ray? |
| Q11118 |
– |
How can I convert CTDI(vol) in mGy and/or DLP in mGy-cm to effective dose in mSv? |
| Q11153 |
– |
CT scan of the eye socket |
| Q11294 |
– |
Risk from medical exams and flying |
| Q11307 |
– |
Risk from diagnostic imaging procedure |
| Q11404 |
– |
Scattered x rays during podiatry exam |
| Q11455 |
– |
Exposure from machines that are not in use |
| Q11550 |
– |
Comparison of x ray vs CT for TMJ study |
| Q11591 |
– |
Gonadal dose from bone density measurements |
| Q11603 |
– |
Dose to the patient due to various knee procedures |
| Q11607 |
– |
Worried about holding a patient during an x-ray procedure |
| Q11614 |
– |
CT radiation dose misinformation |
| Q11710 |
– |
How do you calculate an effective dose for CT given the CTDIvol and DLP? |
| Q11749 |
– |
Risk from CT chest angiography |
| Q11781 |
– |
Scatter radiation dose from elbow x ray |
| Q11836 |
– |
Dose from CT colonoscopy |
| Q12033 |
– |
Radiation dose from discogram |
| Q12047 |
– |
Why don't we use MRI instead of CT for abdominal studies? |
| Q12077 |
– |
Are Omnipaque and barium used in fluoroscopy studies radioactive? |
| Q12216 |
– |
Head CT dose from older exams |
| Q12342 |
– |
Radiation dose and cellular repair |
| Q12437 |
– |
Short-term vs long-term radiation exposure |
| Q12472 |
– |
Dose to areas near the x-ray tube, but not in primary beam |
| Q12486 |
– |
Can radiation of the head cause Alzheimer’s disease? |
| Q12746 |
– |
When is patient lead shielding necessary? |
| Q12778 |
– |
X-ray risk and is the CT/x ray really necessary? |
| Q12820 |
– |
Dose from multiple x rays are generally not additive |
| Q12830 |
– |
Hypothetical risks do not mean you are doomed to cancer |
| Q12948 |
– |
Body size can affect radiation dose |
| Q12962 |
– |
Fluoroscopy dose factors and terms |
| Q13013 |
– |
The DLP value is used to estimate your dose |
| Q13118 |
– |
Explanation of CT terms—multiplanar, VRT, scout, and phantom CM of body |
| Q13194 |
– |
100 mrem from diagnostic x rays—the risk in perspective |
| Q13211 |
– |
Protective covering may not be best practice |
| Q13510 |
– |
Could a CT scan result in fertility or genetic effects? Can I reverse the effects? |
| Q13538 |
– |
Dose and Risk from High Resolution Chest CT (HRCT) |
| Q13565 |
– |
A simple explanation of CTDI-vol and DLP |
| Q13600 |
– |
Do I emit radiation after having an x ray? |
| Q13626 |
– |
CT: Low risk with significant benefit |
| Q13689 |
– |
Skin dose, total dose, and effective dose are not equal |
| Q13694 |
– |
Single CT/CT series used to gain lots of information |
| Q13908 |
– |
Same CTDIvol or DLP results in different effective dose for different procedures |
| Q14100 |
– |
Explanation of the risk from medical x rays and putting the risk into perspective |
| Q14123 |
– |
No increased risk of medical issues or cancer from childhood medical x-rays |
| Q14228 |
– |
Underwire bra will not affect CT image |
| Q14287 |
– |
What is the risk from mammography? |
| Q14389 |
– |
Multiple diagnostic x rays days, weeks, or years apart do not result in an increase in risk |
| Q14391 |
– |
I am so scared after having two CT scans |
| Q14413 |
– |
Effects on brain from head CT |
| Q14662 |
– |
Many types of oversight to assure medical x rays are safe |
| Q14907 |
– |
There is no limit for patient dose and worker dose limit is considered minimal risk |
| Q15024 |
– |
Dose to visitors in a CT room is very low |
| Q15027 |
– |
Medical x rays are beneficial, and risk is not cumulative |
| Q15054 |
– |
Why there may be differences in assessment of risk |
| Q15061 |
– |
Why different online calculators give different results; all results low risk |
| Q15076 |
– |
Should I get a 2D or 3D mammogram or digital breast tomosynthesis? |
| Q15101 |
– |
Having CT scans or diagnostic x rays should not interfere with life decisions |
| Q15163 |
– |
Shielding patient with lead apron is not recommended |
| Q15333 |
– |
A high reported fluoroscopy dose is likely a skin dose, which has a different concern |
| Q15438 |
– |
Minimal, to no radiation dose outside the imaged area |
| |
| Dental |
| Q1713 |
– |
Dental doses |
| Q3992 |
– |
Frequent dental x rays |
| Q4322 |
– |
Dental x ray concerns |
| Q4411 |
– |
Dental x rays and sore throat |
| Q8152 |
– |
Uranium in glaze on porcelain denture teeth |
| Q8568 |
– |
Radioactivity in porcelain dentures and crowns |
| Q10565 |
– |
Safe time between repeat x-ray procedures |
| Q10700 |
– |
Risk from dental x rays |
| Q10721 |
– |
Why repeatedly operate a dental x-ray machine with no patient receiving an x ray? |
| Q10785 |
– |
Radiation exposure from handheld dental x-ray units |
| Q10794 |
– |
Radiation exposure from older dental x-ray units and risk of brain cancer |
| Q10936 |
– |
Doses from digital imaging in dental radiology |
| Q10940 |
– |
Panoramic (panoral) x rays taken for TMJ issue |
| Q11055 |
– |
Dental x-ray dose |
| Q11072 |
– |
X-ray settings for a six year old |
| Q11136 |
– |
Am I being overexposed to x rays in an open bay dental layout? |
| Q11138 |
– |
Radiation doses from cone-beam CT |
| Q11139 |
– |
Is there a radiation-free alternative for panoramic (panoral) dental x rays? |
| Q11372 |
– |
Porcelain and zirconia crowns |
| Q11426 |
– |
Titanium dental implants |
| Q11492 |
– |
Exposed to too much radiation during dental x rays |
| Q11712 |
– |
Radiation dose from multiple dental exams |
| Q11819 |
– |
Worries about dental radiation side effects |
| Q12152 |
– |
Wearing a protective lead apron on my back for a panoramic (panoral) x-ray exam |
| Q12162 |
– |
Radiation risk from dental implants |
| Q12200 |
– |
Safety features of dental x-ray exposure switch |
| Q12203 |
– |
Remote-control exposure switch for dental x rays |
| Q12477 |
– |
How x-ray dose factors are set for panoramic (panoral) dental x ray |
| Q12492 |
– |
Did I receive too much radiation dose from a panoramic (panoral) x ray? |
| Q12809 |
– |
Associated risk from many x rays on a single tooth |
| Q12900 |
– |
Immediate burning sensation after x ray due to cause other than the x ray |
| Q13077 |
– |
Radiation exposure from Cad/Cam digital dentistry |
| Q13098 |
– |
Being in area of x ray does not result in significant dose |
| Q13391 |
– |
No dose to baby from mother's dental x rays |
| Q13641 |
– |
Panoramic (panoral) (dental OPG) x ray and some common safety concerns explained |
| Q13785 |
– |
Detailed explanation of root canal and benefits of cone beam computed tomography (CBCT) to image area |
| Q13809 |
– |
Panoramic (panoral) vs. 3D cone beam and associated low dose |
| Q13960 |
– |
How often should a dentist perform x rays? |
| Q14048 |
– |
Lead apron no longer required due to enhanced collimation |
| Q14272 |
– |
Panoramic (panoral) "test" mode does not generate x rays and helps ensure correct patient positioning |
| Q14523 |
– |
Low dose from cone beam CT (CBCT) |
| Q14547 |
– |
CBCT explained |
| Q14581 |
– |
Operation of dental panoramic (panoral) explained |
| Q14752 |
– |
Reasons for using a positioning indicator device |
| Q14962 |
– |
Pushing button does not mean radiation is being emitted |
| Q15149 |
– |
Comparing CBCT vs. standard panoramic |
| Q15377 |
– |
Handheld dental x-ray units are safe |
| |
| MRI |
| Q9517 |
– |
Dosimetry for ultrasound and MRI technologists |
| Q10931 |
– |
Risk of dislodging blood clots from magnetic resonance imaging (MRI) |
| Q13577 |
– |
Risk from MRI vs. cellphone |
| Q14004 |
– |
Risks from MRI |
| |
| Therapy - Radiation Oncology |
| Q8592 |
– |
Probability of secondary cancer after radiation therapy |
| Q10964 |
– |
Can radiation affect hearing aids? |
| Q11069 |
– |
Caregiver safety when patient is administered radium-223 |
| Q11311 |
– |
Risk from implanted radon seeds |
| Q11501 |
– |
Breast-feeding during radiation therapy for a brain tumor |
| Q11740 |
– |
Radiation dose from Gamma Knife treatments |
| Q12494 |
– |
Radiation effects from ingestion of thorium dioxide |
| Q12708 |
– |
Each radiation therapy treatment is patient specific |
| Q12761 |
– |
Radiation therapy prescription and application of dose painting and dose fractionation |
| |
| Therapy - Nuclear Medicine |
| Q12945 |
– |
Decay results in radioactive contamination going away |
| Q13563 |
– |
Risks from caring for an I-131 therapy patient |
| |
| Worker Issues |
| Q7265 |
– |
Computed Tomography Dose Index (CTDI) |
| Q7303 |
– |
Dose limit to thyroid |
| Q10251 |
– |
Veterinary nurse |
| Q10577 |
– |
Film speed vs. radiation dose to patient |
| Q10779 |
– |
How can I describe dental exposures to patients? |
| Q11012 |
– |
Radiation safety certification for dental personnel |
| Q11177 |
– |
Calculating CT dose from control parameters |
| Q11588 |
– |
Radiation worker exposure without protective equipment |
| Q12793 |
– |
Applying time, distance and shielding if in fluoroscopy room to assure no risk |
| Q13454 |
– |
What is the risk to the dentist/hygienist from a handheld x-ray device? |
| Q13700 |
– |
Dose from personal medical procedures is not included in worker dose limits |
| Q13856 |
– |
Concerned about dose after forgetting lead apron |
| Q14412 |
– |
Radiation dose from dental cone-beam computed tomography systems (CBCT) |
| Q14893 |
– |
No risk from being in area during an x ray |
| Q15488 |
– |
Operator doses from handheld dental x-ray devices are low |
| |
| Pediatric Issues |
| Q7748 |
– |
Worried about head CT on daughter |
| Q10528 |
– |
Is a CT scan more dangerous than a bone scan? |
| Q10552 |
– |
Radiation exposure to infant from barium swallow study |
| Q10592 |
– |
Doses from a barium swallow study |
| Q11088 |
– |
Risk from dental procedures on child using adult settings |
| Q11145 |
– |
X rays and childhood leukemia |
| Q11299 |
– |
Cephalometric and panoramic x-ray doses |
| Q11310 |
– |
Effects of head CT scan on infant |
| Q11472 |
– |
Shielding for patient during forearm x rays |
| Q11859 |
– |
CT scan comparison between a newborn and five-year-old patient |
| Q12016 |
– |
Radiation risk from a head CT and scoliosis screening exam |
| Q12236 |
– |
X-ray collimator leakage radiation |
| Q12483 |
– |
Risks of pediatric dental x rays |
| Q12489 |
– |
Recent articles relating head CTs to increased cancer risk in children |
| Q12685 |
– |
Explanation of millisievert and effective dose |
| Q12706 |
– |
Fluoroscopy dose variables and risk |
| Q12730 |
– |
Risk from being in an adjacent area during an x-ray procedure |
| Q12748 |
– |
No gonad shielding for swallowed battery |
| Q12836 |
– |
How an x ray interacts and can a metal button increase patient dose? |
| Q12892 |
– |
The majority of an x-ray dose is to a limited area and gonadal shielding is not necessary |
| Q13150 |
– |
Dose from multiple x rays is negligible risk to premature baby |
| Q13164 |
– |
CT of child—risk in perspective |
| Q13717 |
– |
Panoramic x ray |
| Q13997 |
– |
No fertility or testicular cancer concerns needed from childhood x ray |
| Q14888 |
– |
Standard x rays are very low dose and do not increase risk |
| Q15112 |
– |
Lead apron no longer consider appropriate for patient safety |
| Q15128 |
– |
Radiation dose, age when dose occurred, and spacing of dose can all effect risk |
| Q15440 |
– |
CT values, CTDIvol, and DLP explained |
| Q15455 |
– |
No danger of cancer, autism, or fertility from pediatric x rays |
| |
| Miscellaneous |
| Q10518 |
– |
Time, distance, and shielding precautions after iodine-125 seed permanent implant |
| Q10831 |
– |
Is radiation retained in clothes and other common material? |
| Q10975 |
– |
Are there regulations limiting radiation doses from medical procedures? |
| Q11109 |
– |
Radiation risk from holding a patient without a protective apron during an x-ray procedure |
| Q11479 |
– |
Ultrasound damage to reproductive organs |
| Q12755 |
– |
Using linear no threshold (LNT) to determine risk |
| Q12835 |
– |
Explanation of effective dose (mSv), absorbed dose (mGy), and dose-length product (DLP) |
| Q12965 |
– |
Effective dose and my individual risk |
| Q13190 |
– |
Old x-ray machines can change from film to digital image |
| Q13191 |
– |
AAPM position statement revision due to caution, not new evidence |
| Q13292 |
– |
Will my clothing, cell phone, keys, or a wallet increase my radiation dose? |
| Q13516 |
– |
Possible deterministic effects change with skin dose |
| Q13532 |
– |
Medical x rays did not cause genetic condition |
| Q13535 |
– |
Putting medical dose and 100 mSv in perspective |
| Q13693 |
– |
Bone Density/DEXA dose and risk |
| Q13720 |
– |
Whole-body vs. organ dose |
| Q13829 |
– |
Cumulative CT scan exposure in children |
| Q13844 |
– |
Safety features on x-ray machines |
| Q13862 |
– |
Risk of pelvic x ray during pregnancy |
| Q13883 |
– |
What does "too much radiation" mean? |
| Q14203 |
– |
Radiation risk from dental panoramic x rays is minimal |
| Q14655 |
– |
Radiation dose from diagnostic medical procedures is not cumulative |
| Q14688 |
– |
Important difference between procedure tissue dose, patient radiation dose, worker dose limits, and background dose |
| Q14694 |
– |
Explaining some dose metrics—millisieverts (mSv), milligray (mGy), and DAP |
| Q14719 |
– |
Diagnostic CT does not significantly increase cancer risk associated with secondhand smoke |
| Q14797 |
– |
Why don’t clinicians provide effective dose to patients? |
| Q14961 |
– |
Being in same building with x-ray equipment does not result in significant dose |
| Q14969 |
– |
Many x rays over a few months does not result in significant increase in risk |
| Q15165 |
– |
Similar to exposure to the sun, exposure from medical radiation procedures is not cumulative |
| Q15171 |
– |
Minimal risk, significant benefits from medical procedures involving radiation exposure |
