Impact of Multiple CT Scans and X-rays on Radiation Exposure and Health

Hello, I would like to inquire about the effects of multiple computed tomography (CT) scans in a short period of time on the body?

Hello Dr.
Wang, I have a few questions to ask you.
I had a chest X-ray at the beginning of January, a CT scan of the abdomen (with contrast) in mid-February, and a low-dose CT scan of the lungs at the beginning of April.
However, due to issues with breath-holding, the hospital had to repeat the lung scans four times before they were satisfactory.
In total, I underwent 1 chest X-ray, 1 CT scan (with contrast), and 4 low-dose lung CT scans within three months.
I would like to ask you three questions: 1.
Is the total radiation dose I received in these three months significant? 2.
Is there a considerable impact on my body from having four low-dose lung CT scans in one day? Is it safe to have them done consecutively like that? 3.
Will the radiation exposure from these tests over the past three months have a significant impact on my health in the future? Thank you for your help in clarifying these concerns; I greatly appreciate it.

Mr. Zhang, 30~39 year old female. Ask Date: 2020/04/13

Dr. Wang Yifen reply Radiology

Hello Mr.
Zhang,
1.
According to the International Commission on Radiological Protection (ICRP) report 103, doses below 100 millisieverts (mSv), whether single or multiple exposures, do not cause clinical functional impairment.
The radiation doses from the examinations you mentioned will not exceed 100 mSv, therefore they will not cause any clinical functional damage to you.
2.
Regarding the repeated low-dose chest CT scans performed four times, it is reasonable for the patient to undergo more than one X-ray exposure to achieve the necessary image quality for diagnosis.
Even with four repetitions of low-dose chest CT scans, the radiation exposure remains within the low-dose range.
3.
The use of radiation in the medical field is increasing.
To achieve diagnostic or therapeutic goals and provide necessary information for physicians to diagnose or treat, it is advisable to follow your doctor's instructions regarding radiation-related examinations or treatments, as the health benefits outweigh the effects of radiation.
If you have concerns, please communicate with your physician before proceeding with the examination.
Wishing you safety and good health.

Reply Date: 2020/04/13

More Info

Dear Patient,
Thank you for your inquiry regarding the impact of multiple CT scans and X-rays on radiation exposure and health. It's understandable to have concerns about radiation exposure, especially when multiple imaging studies are involved. Let’s address your questions one by one.

1. Total Radiation Exposure Over Three Months: The radiation dose from various imaging studies can vary significantly. For instance, a standard chest X-ray typically delivers about 0.1 mSv (millisieverts), while a conventional abdominal CT scan with contrast can deliver approximately 10-20 mSv, depending on the specific protocol used. Low-dose lung CT scans are designed to minimize radiation exposure and usually deliver around 1-3 mSv per scan. If you underwent one chest X-ray (0.1 mSv), one abdominal CT (let's assume 15 mSv), and four low-dose lung CTs (let's estimate 2 mSv each), your total exposure would be approximately:
- Chest X-ray: 0.1 mSv
- Abdominal CT: 15 mSv
- Low-dose lung CTs: 4 x 2 mSv = 8 mSv
Total: 0.1 + 15 + 8 = 23.1 mSv
This amount of radiation is significant but still below levels that are typically associated with immediate health risks. According to the International Commission on Radiological Protection (ICRP), doses below 100 mSv are not expected to cause any acute health effects.

2. Impact of Repeated Low-Dose Lung CT Scans: While low-dose CT scans are designed to reduce radiation exposure, repeating them multiple times in a short period can still accumulate radiation dose. The concern with doing four scans in a single day, even if they are low-dose, is not just the cumulative dose but also the potential for increased risk of radiation-induced effects, albeit very small. Generally, it is advisable to space out imaging studies to allow for better assessment and to minimize cumulative exposure. If multiple scans are necessary, your healthcare provider should weigh the benefits against the risks and consider alternative imaging methods if appropriate.

3. Long-Term Health Effects: The long-term effects of radiation exposure depend on several factors, including the total dose received, the age at exposure, and individual susceptibility. While the risk of developing cancer increases with higher cumulative doses, the increase in risk from doses below 100 mSv is considered to be very low. For context, the lifetime risk of developing cancer from radiation exposure is estimated to increase by about 0.5% for every 10 mSv of exposure. Therefore, your total exposure of approximately 23.1 mSv might slightly increase your risk, but it is still relatively low compared to other risk factors for cancer.

In conclusion, while it is important to be mindful of radiation exposure, the medical benefits of imaging studies often outweigh the risks, especially when they are necessary for diagnosis and treatment. It is crucial to maintain open communication with your healthcare provider about the necessity of each imaging study and to discuss any concerns you may have regarding radiation exposure. If you have further questions or if you are feeling anxious about your health, consider discussing these feelings with your doctor, who can provide reassurance and guidance tailored to your specific situation.

Wishing you good health,
Doctor Q&A Teams

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