Concerns About CT Scan Radiation Exposure and Its Health Risks

I am very concerned about the potential harm from radiation exposure during a CT scan?

Hello Director Wang,
I am a patient from the Taipei Chang Gung Emergency Department on the early morning of March 27.
I am just 22 years old and experienced pain in my lower right abdomen that day.
I underwent a CT scan without the administration of contrast agents.
Since the scan, I have been experiencing headaches and dizziness.
Could this be caused by the CT scan? I later had an EEG, which returned normal results, and a neurologist diagnosed me with anxiety disorder.
However, I am still quite concerned and would appreciate your clarification.
Thank you.
Additionally, I have some concerns regarding the CT scan:
1.
I called the Chang Gung laboratory to inquire about the radiation exposure dose, which they said was less than 7 mSv.
Isn't the typical dose at least 10 mSv? Given that I am only 22 years old, what is the lifetime attributable cancer risk associated with 7 mSv? Is it indeed as low as what is mentioned online or as stated by the X-ray risk calculator, which suggests an increase in cancer risk of 4 to 6 per 10,000? I apologize for my worries, especially after seeing reports from Epoch Times stating that CT scans cause cancer in 30,000 people each year, the majority of whom are "young people."
2.
Regarding the CT scan of the abdomen, which included both longitudinal and transverse sections, can you clarify whether these images were synthesized by the computer or if two separate scans were taken? After the abdominal CT, I noticed images of the pelvis and prostate.
Could this have any adverse effects on my body? Why was it not noted as a CT of the abdomen and pelvis?
3.
As I am only 22 years old, I am concerned about potential long-term effects.
On the day of the scan, I took two cycles of inhalation and exhalation.
Does this mean I was scanned twice? Also, I was wearing a plain cotton top and sweatpants and did not change into a gown.
I was not protected by lead shielding while lying directly in the machine.
Could this pose any risk to other areas, such as my brain, or even result in scanning the wrong area?
4.
Given my concerns about the potential harm from the CT scan and my lack of a history of blood disorders, would you recommend that I undergo routine blood tests for monitoring? How often should these tests be performed?
Thank you very much for your assistance.

Hong Tongxue, 20~29 year old female. Ask Date: 2018/04/18

Dr. Wang Yifen reply Radiology

1.
The CT images are synthesized by a computer to form the final images.
The number of breaths taken during the examination, as well as the scanning area and breath-holding time, varies from person to person.
Since your main complaint is right lower abdominal pain, the typical scanning range is the entire abdomen, which includes the pelvis and prostate.
The reason it is not specifically labeled as a CT of the abdomen and pelvis is related to the hospital's examination order management system.
2.
Regarding radiation exposure from examinations, procedures are arranged only when the health benefits outweigh the risks of radiation, in order to achieve diagnostic or therapeutic goals and provide necessary information for the physician's diagnosis or treatment.
A computed tomography (CT) scan, aside from the risk of radiation, will not have any adverse effects or sequelae on any part of your body, nor will it cause headaches or dizziness.
There is no need to undergo any additional examinations due to this scan, so please do not worry excessively.
However, due to the cumulative effects of radiation, unnecessary medical radiation exposure should be avoided.
If you have any concerns, please communicate further with your physician before undergoing the examination.

Sincerely,
Yi-Fen Wang

Reply Date: 2018/04/18

More Info

When it comes to concerns about radiation exposure from CT scans, it is essential to understand both the risks and the benefits associated with these diagnostic procedures. CT scans, or computed tomography scans, utilize X-rays to create detailed images of the body's internal structures. While they are invaluable tools for diagnosing various medical conditions, they do involve exposure to ionizing radiation, which can pose potential health risks.

Understanding Radiation Exposure
The radiation dose from a CT scan can vary depending on the type of scan and the area being examined. For example, a typical abdominal CT scan can expose a patient to approximately 7 mSv (millisieverts) of radiation. To put this into perspective, the average person is exposed to about 3 mSv of natural background radiation per year. Therefore, a single abdominal CT scan can equate to about two years of natural background exposure.

Regarding your specific concern about the lifetime cancer risk associated with a 7 mSv exposure, studies suggest that the risk of developing cancer from radiation exposure is relatively low. The National Cancer Institute estimates that the risk of cancer increases by about 0.05% per mSv of radiation exposure. Therefore, a 7 mSv exposure could theoretically increase your lifetime cancer risk by about 0.35%. This is a small increase compared to the baseline risk of developing cancer, which is about 38% for the average person.

Addressing Symptoms After a CT Scan
You mentioned experiencing headaches and dizziness after your CT scan. It is important to note that these symptoms are not typically associated with radiation exposure from a CT scan. Instead, they may be related to anxiety or other factors unrelated to the imaging procedure. If these symptoms persist, it would be advisable to consult with your healthcare provider to explore other potential causes.

Clarifying CT Scan Procedures
Regarding your questions about the specifics of the CT scan you underwent, it is common for a single CT scan to capture multiple planes of imaging, which may include both axial (cross-sectional) and coronal (longitudinal) views. This is done through a process called reconstruction, where the computer synthesizes images from the data collected during the scan. The presence of images of the pelvis and bladder in your abdominal CT scan is not unusual, as the scan may cover a broader area than initially specified.

As for concerns about the lack of lead protection during the scan, while lead aprons are often used to shield sensitive areas from unnecessary radiation, the radiation dose from a single abdominal CT scan is generally considered safe and unlikely to cause harm to other body parts, including the brain.

Future Monitoring and Health Checks
Given your age and the absence of any significant medical history, routine blood tests or follow-up imaging are not typically warranted solely based on a single CT scan. However, if you have ongoing concerns or develop new symptoms, it is always prudent to discuss these with your healthcare provider. They can guide you on the appropriate follow-up care based on your individual health needs.

Conclusion
In summary, while CT scans do involve radiation exposure, the associated risks are generally outweighed by the diagnostic benefits they provide. It is crucial to have open discussions with your healthcare provider about any concerns you may have regarding radiation exposure and to ensure that any imaging studies performed are medically justified. If you have further questions or experience ongoing symptoms, do not hesitate to seek medical advice. Your health and peace of mind are paramount.

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