In our time, going to the hospital to register and the doctor to order you to have a CT done is as common as having breakfast.
Don't look at its loud name, when it sounds like it's a "computed tomography", it seems to be tall and tall with the computer, but do you know that this thing is actually an X-ray to illuminate you, doesn't it sound a little panicked?
Don't be nervous, let's take a look at it today, what is this CT, and how much impact does it have on our bodies?
1. Introduction to CT examination
Let's start with what CT is. Do you think, if the doctor can have the superpower to see through your body at a glance, then wouldn't it be easy to check the disease? CT, that's pretty much the truth.
It uses a special X-ray beam that sweeps through all angles of your body, and then the computer processes it to produce a cross-sectional image of your body.
It's like if you take a watermelon and don't cut it, you can't see anything just by looking outside. But CT is like slicing a watermelon for you, and you can see what's going on in each layer.
At this point, you may be asking, isn't CT just an advanced version of X-ray? CT is much more complicated than taking an X-ray in a small clinic outside, and the amount of information it can provide is much larger, especially for diseases such as cerebral infarction and tumor.
However, although this technique is good, it is not suitable for everyone. For example, if some people are allergic to contrast agents, then CT with contrast is not suitable. So, don't look at the doctor to give you a bill, you have to understand your situation clearly.
2. Radiation dose in CT examination
Let's talk about radiation. The word radiation, as soon as you hear it, makes people's hearts furious, as if as soon as it shines, people will become fluorescents. But in fact, we are exposed to radiation every day, whether it is the sun's exposure or the electrical appliances at home, radiation is everywhere.
Not to mention CT, if you fly for hours on a plane, the radiation will be higher than if you are on the ground. Not to mention those smokers, who smoke a lot more cigarettes than you can do a CT scan in a year.
So, at the end of the day, how much damage does CT radiation do to the body? Actually, it depends on how many times you take it. There is a concept in medicine called "dose". Generally speaking, if you do a chest X-ray, the radiation dose is about 0.1mSv, which has very little effect on the body.
Moreover, the doctor does not let you lie down in the CT machine when you have nothing to do, they have a set of strict standards, and they think that a single dose of 50mSv, or a cumulative dose of 100mSv, is the safety line. Beyond that, you really have to think about it.
But you have to know that these are based on the premise that you don't go for CT every day. It's like taking medicine, the right amount is a cure, and the excessive amount is to find guilt. Therefore, we ordinary people, there is really no need to be nervous about doing a CT occasionally.
3. Risks and misunderstandings of CT examination
When it comes to CT scanning, many people first think of radiation, and indeed, radiation is a risk factor that cannot be ignored in CT scanning. But there are many misunderstandings in this. First of all, although the radiation dose of CT is higher than that of ordinary X-rays, it is strictly controlled.
According to the recommendations of the International Commission on Radiological Protection (ICRP), the ALARA principle of "lowest possible reasonable level" should be followed for diagnostic radiation, which means that the radiation dose should be minimized without compromising the quality of diagnosis.
However, many people have an instinctive fear of the word "radiation", believing that once they undergo a CT scan, it is equivalent to an increased risk of cancer.
In fact, the relationship between low-dose radiation (such as those used in diagnostic CT scans) and increased cancer risk is not linear, according to available scientific research.
Many studies have shown that the health effects of low doses of radiation are far less than the general public belief. In fact, background radiation levels in nature also vary greatly from region to region, but there is no clear evidence that people with low radiation background have lower rates of cancer than people with high background radiation.
4. Scope and limitations of CT examination
As a powerful medical diagnostic method, CT has a wide range of applications. In acute trauma, tumor detection, infection assessment, vascular disease diagnosis, etc., CT examination can provide high-resolution images to help doctors make accurate diagnoses.
For example, for the diagnosis of stroke, CT can quickly distinguish whether it is caused by hemorrhage or ischemia and thus guide emergency treatment. In the evaluation of tumors, CT can not only help to detect tumors, but also assess the size and shape of the tumors, and whether they have invaded surrounding tissues or metastasized in distant areas.
However, CT is not without limitations. First of all, for pregnant women, especially in the first trimester, CT is generally not recommended because the fetus is extremely sensitive to radiation, unless it is deemed necessary after a rigorous evaluation by a doctor.
Second, in children, where the long-term effects of radiation can be more significant due to their more sensitive tissues, more caution is needed when performing CT scans in children to ensure that they are only done when absolutely necessary.
In patients with renal function problems, the use of iodine-containing contrast agents may increase the risk of acute kidney injury, so it is important to assess the patient's kidney function before performing CT with contrast.
In addition, in patients with allergies, contrast agents may cause allergic reactions, which is why a careful history is required before a CT scan.
Fifth, the choice of MRI
In the field of modern medical imaging, CT and MRI are two commonly used examination modalities, each with its own strengths. Due to its fast speed and high resolution, CT examination is particularly important in the case of acute stroke and complex fractures.
However, MRI has incomparable advantages in soft tissue contrast, such as the detection of lesions in brain tissue, spinal cord, joints and muscles. Instead of using radiation, MRI uses a powerful magnetic field and radio waves to scan the human body.
The choice between CT and MRI depends on the patient's specific condition and the purpose of the examination. For example, if a hemorrhagic or ischemic stroke needs to be diagnosed quickly, CT is usually preferred because it can be done quickly and immediately rule out bleeding.
For tumors, degenerative diseases, certain chronic pains, and other conditions, MRI may be more suitable because it can provide more detailed images of soft tissues.
However, MRI is a longer examination time and is not appropriate for patients who cannot cooperate with the examination (eg, children with severe anxiety, pain, or inability to lie down calmly).
In addition, metal implants (such as certain types of pacemakers, cochlear implants, etc.) may interact with the magnetic field of MRI and pose a danger, so these patients cannot undergo MRI examinations.
epilogue
In this era of rapid technological development, medical imaging technology has become an indispensable part of modern medicine.
CT examination, as an important means, has undoubtedly greatly improved the accuracy and efficiency of disease diagnosis.
However, no technique is perfect, and CT is no exception.
It is essential for patients to understand the principles, scope of application, risks and limitations of CT examination. This not only helps patients worry less unnecessarily, but also enables them to make more rational decisions when necessary.