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6 Common Misconceptions About Radiology and Medical Imaging: What You Need to Know

You walk into a radiology clinic. You're anxious. You've heard so many things:

"Radiation causes cancer..." "MRIs hurt..." "I can't have imaging because I have an implant..." "Pregnant women can't have CT scans..."

Every day we see patients stressed by myths about radiology. This anxiety sometimes prevents them from accessing diagnoses that could change their lives.

This article gives you the REAL facts, sourced. No approximations. No exaggerations.

Myth #1: "Radiation causes cancer"

The belief

"If I get a scan, I'll get cancer from the radiation."

The reality

The doses used in diagnostic imaging are VERY low.

Here is the data verified with international medical literature (RadiologyInfo.org, NIH, ICRP):

Exam
Effective Dose

Equivalent

Chest X-ray
0.065 mSv
≈ 10 days of natural radiation
Scanner (head)
1.9 - 2.1 mSv
≈ 7-8 months of natural radiation
CT scan (chest)
7.5 mSv
≈ 2-3 years of natural radiation
MRI
0 mSv
Zero ionizing radiation

Annual natural exposure (background): 2-3 mSv according to ICRP (cosmic radiation, natural radon)

At what level does it become dangerous?

According to ICRP 103 recommendations (international reference body), the risk of cancer only begins to increase from a cumulative exposure of 50 mGy (fetus) or at very high levels of occupational exposure (20 mSv/year).

To give you some perspective:

  • A chest CT scan = 7.5 mSv
  • Danger threshold = 50 mGy (fetus) or 100+ mSv (adult)
  • Ratio: You should have 6-13 chest scans to reach a theoretical threshold of concern

No patient who has undergone standard diagnostic imaging will receive these doses.

Radiation in diagnostic imaging is safe when medically justified.

The principles applied:

  • ALARA (As Low As Reasonably Achievable): Use the MINIMUM doses
  • Imaging should only be performed when there is a medical reason
  • Avoid unnecessary repeated examinations

Sources:

  • American College of Radiology, RadiologyInfo.org
  • ICRP Publication 103, Recommendations of the International Commission on Radiological Protection
  • NIH, National Center for Biotechnology Information

Myth #2: "MRIs hurt"

The belief

"An MRI is like being enclosed in a noisy machine. I'm claustrophobic. It's going to hurt."

The reality

An MRI does NOT hurt.

Here's what's really happening:

During the exam:

  • You are lying on a comfortable table
  • You slide into a machine (cylindrical or "open" depending on the type)
  • The machine makes noise (repetitive sounds, but not dangerous - just noisy)
  • You remain still for 15-30 minutes
  • The radiologist is in another room but can hear you and communicate

What you are feeling:

  • Zero pain
  • A slight stinging sensation may occur if you are using a contrast agent (very rare)
  • Light vibration
  • Noise (you can request earplugs)

After the exam:

  • No side effects
  • No pain
  • You can resume your activities immediately

For Claustrophobia

Conventional MRI scans can indeed be difficult for some claustrophobic individuals. Available solutions:

✓ Open MRI scanners (less enclosed)
✓ Mild sedation if necessary (discuss with your doctor)
✓ Someone can remain in the room
✓ Emergency stop button for IMMEDIATE termination

An MRI scan doesn't hurt. It can be uncomfortable for some (noise, feeling of being enclosed) but never painful.

Myth #3: "I can't have an MRI because I have an implant"

The belief

"I have a pacemaker / a dental implant / a metal plate. I can never have an MRI."

The reality

That's partially true, but VERY simplified.

Implants are contraindicated (absolutely):

  • Older pacemakers (pre-2010 models)
  • Old brain stimulators
  • Some ferromagnetic vascular metal clips

Safe implants with MRI:

  • Titanium dental implants (non-magnetic)
  • Modern orthopedic plates (surgical stainless steel)
  • Fracture screw
  • Coronary stents
  • Joint prostheses (hip, knee)

CONDITIONAL implants (requires strict protocol):

  • Modern pacemakers "MRI-conditional" (since ~2008)
  • Modern cardiac defibrillators "MRI-conditional"
  • Some recent brain stimulators

Current Data

According to a 2017 NEJM study of 1509 patients with "non-MRI-conditional" pacemakers:

  • 2103 MRI examinations performed using a secure protocol
  • Zero deaths, zero major complications
  • Only 0.4% of tests showed a minor device reset (without clinical consequences)

Conclusion: Even older pacemakers CAN have an MRI, but only in experienced centers with a strict protocol.

What We Do Before Your MRI

  1. Check the EXACT model of your implant (request the implant card)
  2. Consult the manufacturer's database
  3. Assess whether the MRI is truly necessary
  4. If so, program the device in "MRI mode"
  5. Continuous monitoring during the examination
  6. Complete post-exam verification

Having an implant does NOT automatically preclude an MRI. ALWAYS mention your implant BEFORE the examination.

Sources:

  • American College of Cardiology, 2024
  • NEJM, “Safety of Magnetic Resonance Imaging in Patients with Cardiac Devices”
  • Heart Rhythm Society Guidelines

Myth #4: "Pregnant women cannot have scans or X-rays"

The belief

"I'm pregnant. The radiation will harm my baby. There's nothing I can do."

The reality

It's much more nuanced.

Estimated radiation doses to the fetus:

  • Chest X-ray: < 0.01 mGy (the fetus is not in the beam)
  • Abdominal X-ray: 1-4 mGy
  • Pelvic scan: 3-25 mGy
  • Fetal danger threshold (according to ICRP): 50 mGy

In other words: even a pelvic scan remains well below the danger threshold.

Official Recommendations (ACOG 2017, ICRP, ACR)

According to guidelines from the American College of Obstetricians and Gynecologists (Committee Opinion No. 723):

Ultrasound and MRI scans pose no risk. With very few exceptions, radiation exposure during an X-ray, CT scan, or nuclear imaging procedure is far less than what could cause harm to the fetus.

Principles:

  1. MRI is safe at all stages of pregnancy (zero ionizing radiation)
  2. X-rays are safe if medically indicated (very low doses).
  3. Scanners should be evaluated on a case-by-case basis (benefits vs. risks).
  4. Never refuse necessary imaging out of fear of radiation

Example: Suspected Pregnant Pneumonia

Common scenario: Pregnant woman, fever, respiratory symptoms. Chest X-ray?

  • Fetal dose: ~0.01 mGy
  • Risk : Zero (well below the 50 mGy threshold)
  • Benefit: Diagnosis of potentially serious pneumonia
  • Decision: X-ray justified

The risk of not diagnosing outweighs the radiological risk.

A pregnant woman should not refuse necessary imaging for fear of radiation.

But she must not do unnecessary imaging.

Always inform us of your pregnancy BEFORE any examination. This allows us to adapt the protocol (e.g., reduce the number of MRI sequences, limit the contrast).

Sources:

  • ACOG Committee Opinion No. 723, 2017
  • ICRP Publication 84, Pregnancy and Medical Radiation
  • American College of Radiology, ACR Manual on MR Safety

Myth #5: "AI will replace radiologists"

The belief

"With AI, radiologists will soon no longer be needed."

The reality

No. AI will never have that power.

What AI CAN Do

  • Analyze millions of images quickly
  • Recognizing patterns
  • Report "suspicious" areas
  • Perform a preliminary sorting (good/bad image)
  • Accelerating the detection of certain pathologies

What AI CANNOT Do

  • Understanding the patient's clinical context
  • Decide which treatment is appropriate
  • Managing complex or ambiguous cases
  • Taking responsibility for a diagnosis
  • Explain the results to the patient with empathy
  • Having nuanced clinical judgment

The Future Role of AI

AI will be a super-intelligent assistant to the radiologist:

  • Treat MORE patients
  • Make FEWER human errors
  • Having MORE time for complex cases
  • Reduce mental fatigue

But the clinical decision? That's about the human element.
Always.

Myth #6: "All imaging exams are useful"

The belief

"More imaging = better. Let's do an MRI just to be sure."

The reality

False. Unnecessary imaging causes more problems than it solves.

Why Is This a Problem

  1. False Positives:
    Imaging shows something abnormal that has NOTHING TO DO with your symptom.
  2. Overtreatment
    : Treating something that didn't need to be treated.
  3. Anxiety:
    You see an anomaly in the image that stresses you out for months.
  4. Delays
    While we wait for your MRI "just to check", someone else with a real emergency is also waiting.

How to Know if Imaging Is Really Necessary?

A good question for yourself:
"Will this imaging change my treatment?"

If the answer is NO → you probably don't do it.

Example: Knee Pain

Approach

Result

Approach 1: X-ray first
X-ray: osteoarthritis. Treatment: physiotherapy + anti-inflammatories. Effective.
Approach 2: MRI "just to see"
MRI: small meniscal tear. But treatment... still physiotherapy. You panicked unnecessarily.

Conclusion: The MRI was unnecessary. It didn't change the treatment, but it did create anxiety.

Imagery is not insurance against anxiety.

It must serve the DIAGNOSIS and THERAPEUTIC DECISION .

Sources:

  • American College of Radiology, Appropriateness Criteria
  • ALARA Principle, ICRP

What you need to remember

Common Misconception
Reality
Radiation = cancer
Diagnostic doses are safe. The danger begins at doses 6-13 times higher.
The MRI hurts
No. It may be noisy/uncomfortable, but never painful.
Implant = impossible MRI
False. Modern implants can undergo MRI scans with strict protocols. Non-ferromagnetic implants are always safe.
Pregnant = no imaging
False. MRI is safe. X-ray is safe if medically indicated. Do not refuse necessary imaging.
AI replaces the radiologist
No. AI is an assistant. Clinical judgment remains human.
More imaging = better
False. Unnecessary imaging causes more harm. Only justified imaging is beneficial.

Frequently Asked Questions

Q: How many imaging scans can be done per year?

A: There is no fixed limit. It depends on WHY you are doing them.

  • Legitimate medical reason (cancer follow-up, nodule monitoring)? Several examinations per year is OK.
  • Just to reassure ourselves? Zero.

Q: Should I request an MRI instead of a CT scan to avoid radiation?

A: Only if the MRI provides the information we are looking for.

  • MRI is best for: brain, spinal cord, joints, ligaments
  • Scanner best for: lungs, cortical bone, rapid imaging (emergency)
  • X-ray is better for: initial assessment (less radiation)

Each imaging technique has its purpose. It is up to the radiologist to choose the right one.

Q: Are contrast agents dangerous?

A: Modern products are very safe. Severe allergies are rare.

Always report:

  • Prior allergies to a contrast agent
  • Kidney failure
  • Diabetes
  • Asthma

This allows the protocol to be adapted.

Q: Can prenatal imaging (ultrasound) harm the baby?

A: No. Ultrasound uses sound waves, not radiation. It's safe even with repeated exposure.

Final message:
Discernment in imaging

At CID Lausanne, we believe in discernment in imaging.

This is NOT:

  • Perform MORE imaging (overdiagnosis = false positives, anxiety, overtreatment)
  • Perform LESS imaging (under-diagnosis = missed diseases)

It is :

  • RELEVANT imaging
  • At the Right Time
  • For the RIGHT REASON
  • With the RIGHT TECHNIQUES
  • Using ALARA (minimal doses)

Bibliographical references

International Reference Organizations:

  • ICRP (International Commission on Radiological Protection): Publication 103, 84
  • American College of Radiology (ACR): Manual on MR Safety, Appropriateness Criteria
  • ACOG (American College of Obstetricians and Gynecologists): Committee Opinion No. 723
  • FDA (Food and Drug Administration): Radiation Dose Guidance
  • Heart Rhythm Society: MRI Guidelines for Cardiac Devices

Key Studies Cited:

  • Nazarian et al., NEJM 2017: Safety of MRI in 1509 patients with cardiac devices
  • Zghaib & Nazarian, ACC 2024: Current State of MRI With Cardiac Devices A
  • COG 2017: Guidelines for Diagnostic Imaging During Pregnancy and Lactation
  • RadiologyInfo.org: Radiation Safety in Medical Imaging

Make an appointment at CID Lausanne

Contact us

Do you need an image? Do you have questions? Don't panic.

CID Lausanne: Cutting-edge medical imaging for your health

  • Phone : +41 21 310 07 10
  • Website:  www.cidradiologie.ch
  • Address:  Rue du Grand-Chêne 8bis, 1003 Lausanne

Free transportation service available

We explain. We reassure. We treat.

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This article is for informational purposes only. It is not a substitute for professional medical advice. If you have specific questions about your health, consult your doctor or a radiologist.