How much radiation does the body absorb when taking a "film"? The truth is...

When at work: Computer radiation is very strong

When playing with your phone: It’s okay, I can play with it all day

When taking X-rays during physical examinations: No, there is radiation

There are always some friends who hear "shoot a film"

I wish I could escape at the speed of light

But seeing a doctor is like fighting a monster

We can't just confuse people with demons and shout for killing.

The imaging instrument is Sun Wukong's Fiery Eyes and Golden Pupils

Can identify diseases and abnormalities in the body

Get rid of the "demons and monsters" on the road to health

Besides, not all examinations that require "filming" have radiation.

Today I will introduce you to this 0 radiation artifact

Magnetic resonance imaging

Magnetic resonance imaging, or MRI for short, can clearly show the internal structures of the body, such as bones, muscles, joints, blood vessels, and internal organs , and plays a very important role in diagnosing various diseases.

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For example, doctors can use magnetic resonance imaging to detect brain tumors or spinal injuries.

But some friends get scared when they see this test, MRI, which sounds like it involves radiation.

Don't worry! MRI scans are radiation-free!

Magnetic resonance imaging, in layman's terms, is to apply a strong magnetic field to the body, so that the atomic nuclei in the body (our body is about 70% water, and there are many hydrogen nuclei in this water) are arranged in an orderly manner toward the direction of the magnetic field, and then excited by electromagnetic waves of a specific frequency. By capturing the energy released by the atomic nuclei returning to their original state, an MRI signal is formed.

Think of MRI as " 3D eyes ," allowing doctors to see clear three-dimensional views of the body's internal tissues from different angles.

CT and MRI examinations are not opposites, but complementary .

Sometimes, even after a CT scan, the doctor may need to perform an MRI to obtain more detailed information.

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Especially when diagnosing neurological diseases , such as cerebral infarction, brain tumors, intracranial infection, aneurysm, multiple sclerosis, etc.; and soft tissue muscle diseases , such as muscle injury, ligament rupture, tendonitis, etc.

In addition, for lesions in certain special areas, MRI can provide clearer images, which helps in more accurate diagnosis and treatment planning.

Since MRI has no radiation and has a strong resolution, it is particularly accurate in diagnosing diseases of the brain, spinal cord, pelvic organs, heart and large blood vessels, and myocardial infarction...

Image source: Photo Network

Wouldn’t it be better to just go for an MRI?

NO NO NO! You can’t have an MRI whenever you want.

For example, the following people cannot undergo MRI examinations :

1. People who have cochlear implants, pacemakers (except compatible pacemakers), insulin pumps and other electronic devices installed in their bodies.

2. People who have ferromagnetic vascular clips, steel nails and plates, or other metal foreign objects of unknown materials in their bodies.

3. Those with magnetic metal implants in their eyes.

4. People with a history of moderate to severe allergic reaction to contrast agents and renal insufficiency.

In addition, there may be safety risks for some patients to undergo MRI examinations, and they need to undergo a comprehensive evaluation by a doctor to determine whether they need MRI examinations :

1. There are ferromagnetic objects in the patient's body or in the examination area.

2. When performing nasopharyngeal or oral examinations, metal dentures may cause image artifacts.

Upper: Scan of head deformity; Lower: Artifacts caused by interference from dentures

3. During pelvic examination, metal IUDs may cause image distortion.

4. For patients with claustrophobia, family members may need to accompany them.

5. Patients who are unconscious, severely hypoxic, or agitated need their condition to be stabilized before they can safely undergo MRI examinations.

6. Pregnant patients need to wait 3 months before undergoing MRI examination.

The doctor will choose the most appropriate examination method based on the patient's specific situation and diagnostic needs. In a word - listen to the doctor about what examination to do .

1

Before the test

Before an MRI examination, you need to remove all metal objects on your body , such as mobile phones, watches, bank cards, ID cards, keys, lighters, necklaces, earrings, coins, etc.

In addition, pacemakers (except compatible pacemakers), stents made of unknown materials, steel needles and steel plates are not allowed to enter the examination room .

2

Checking

It takes about ten minutes to scan a part of the body with an MRI. Due to the operation of the equipment, there will be a lot of noise, and the patient's cooperation in the examination is required to be very high. When the scan starts, you are not allowed to move .

3

After the inspection

If you have an enhanced MRI (with contrast dye), you may need to stay in an observation room for about 15 to 20 minutes to make sure you have no discomfort.

Statement: This article is a medical-related educational popular science article. It does not involve specific treatment methods or medical behaviors and cannot replace hospital visits.

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Experts who reviewed this article

References

[1]Smits M. MRI biomarkers in neuro-oncology[J]. Nat Rev Neurol, 2021, 17(8):486-500. DOI: 10.1038/s41582-021-00510-y.

[2]Stabile A, Giganti F, Rosenkrantz AB, et al. Multiparametric MRI for prostate cancer diagnosis: current status and future directions[J]. Nat Rev Urol, 2020, 17(1):41-61. DOI: 10.1038/s41585-019-0212-4.

[3]Garg P, Swift AJ, Zhong L, et al. Assessment of mitral valve regurgitation by cardiovascular magnetic resonance imaging[J]. Nat Rev Cardiol, 2020, 17(5):298-312. DOI: 10.1038/s41569-019-0305-z.

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