CT scan, Radiology FAQ

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Understanding Radiation Exposure from Multiple CT Scans: Risks and Safety

Computed Tomography Radiation Hello, Doctor: I underwent a low-dose computed tomography (LDCT) scan (640 slices) in December 2023, which revealed nodules in both upper lungs, and the doctor recommended follow-up. Later, due to some health issues, I had an abdominal CT scan of the...


Dr. Wang Yifen Reply:
According to the information from the American Society of Radiologic Technologists, a single low-dose computed tomography (LDCT) scan has a radiation dose of approximately 2 millisieverts (mSv), while an abdominal computed tomography (including the pelvic region) has a radiation ...

[Read More] Understanding Radiation Exposure from Multiple CT Scans: Risks and Safety


Understanding Radiation Exposure: LDCT vs. Standard CT for Lung Nodules

Computed Tomography Radiation Hello, Director: I previously inquired about the radiation dose from CT scans and would like to ask again if I can choose the LDCT method for monitoring a solid lung nodule on 9/23, or is it necessary to opt for a standard lung CT scan? The doctor me...


Dr. Wang Yifen Reply:
Hello, according to the data from the American Radiologic Technologists website, the radiation dose from a single chest LDCT is approximately 2 millisieverts. In contrast, a standard chest CT scan has a radiation dose of about 7 millisieverts. For lung cancer screening, it is rec...

[Read More] Understanding Radiation Exposure: LDCT vs. Standard CT for Lung Nodules


CT Scan Frequency: Safe Interval for Lung Screening After Abdominal CT

Interval time for computed tomography (CT) scans? If I had an abdominal and pelvic CT scan in mid-March, can I still undergo a low-dose lung CT scan for health screening this year? Would the radiation exposure be too high? How long should I wait between scans? Thank you.


Dr. Wang Yifen Reply:
Hello, yes. The necessity of the X-ray examination is considered, and there are no restrictions on the radiation dose or the number of examinations. If there are any concerns, it is advisable to communicate with your physician before undergoing the examination. Do not avoid the e...

[Read More] CT Scan Frequency: Safe Interval for Lung Screening After Abdominal CT


Understanding Radiation Exposure: Risks and Imaging Options Explained

Radiation Dose Issues Hello Doctor: 1. I have undergone X-rays and CT scans within a short period of one month, accumulating a dose of nearly 40 millisieverts. Is this considered too much radiation exposure in a short time, and does it increase my risk of developing cancer? 2...


Dr. Wang Yifen Reply:
Hello, 1. The necessity of X-ray radiation examinations is considered, and there are no restrictions on the radiation dose or the number of examinations. Diagnostic X-rays are classified as low-dose radiation examinations and are generally considered safe according to literatur...

[Read More] Understanding Radiation Exposure: Risks and Imaging Options Explained


Understanding Radiation Exposure: Risks and Imaging Options Explained

Radiation Dose Issues Hello Doctor: 1. I have undergone X-rays and CT scans within a month, accumulating a dose of nearly 40 millisieverts. Is this amount of radiation exposure in such a short time concerning, and does it increase my risk of developing cancer? 2. Since I had a...


Dr. Wang Yifen Reply:
Hello, 1. The necessity of X-ray radiation examinations is considered without limiting the radiation dose or the number of examinations. Diagnostic X-rays are classified as low-dose radiation examinations and are generally considered safe according to literature reports. 2. T...

[Read More] Understanding Radiation Exposure: Risks and Imaging Options Explained


Understanding Radiation Exposure: Safety Concerns and Accumulation Effects

Radiation issues In April 2024, I underwent 20 X-rays for both shoulders, neck, and spine. In mid-April, another hospital performed 10 X-rays on my neck and shoulders. At the beginning of May, I had a chest X-ray during a health check, and according to the National Health Insuran...


Dr. Wang Yifen Reply:
Hello, the consideration for X-ray radiation examinations is based on the necessity of the examination rather than limiting the radiation dose or the number of tests. X-ray radiation is a form of energy, similar to sunlight, and does not remain in the body after exposure. After a...

[Read More] Understanding Radiation Exposure: Safety Concerns and Accumulation Effects


Understanding MRI Report Delays and Diagnostic Accuracy in Prostate Imaging

Issues with MRI reports and diagnostic accuracy? 1. Previously, I underwent a prostate MRI at a hospital and returned for a follow-up appointment on the date scheduled by the physician. However, the report was not available on that day, and the physician scheduled a second follow...


Dr. Wang Yifen Reply:
Hello, there are many reasons why there may not be a written report following imaging examinations, which are related to the administrative processes of the hospital and the availability and training of radiologists. Different imaging modalities have their own advantages and limi...

[Read More] Understanding MRI Report Delays and Diagnostic Accuracy in Prostate Imaging


Understanding Lung Nodules: X-Ray vs. CT Scan Insights

X-ray examination - nodules Hello Dr. Wang, I would like to ask: 1. In recent years, chest X-rays have consistently shown a small nodule in the right lower lung measuring approximately 0.8 cm, with no change in size. Therefore, in July 2022, I underwent a whole-body CT scan at ...


Dr. Wang Yifen Reply:
Hello, the chest X-ray nodule you described is unlikely to be a hepatic hemangioma. Typically, a lung CT report focuses on whether there are nodules in the lung parenchyma. If nodules are consistently seen on chest X-rays but not on CT scans, it is important to consider extra-pul...

[Read More] Understanding Lung Nodules: X-Ray vs. CT Scan Insights


Is Your Medical Radiation Exposure Safe? Understanding Dosage Limits and Risks

Is the level of radiation safe? Hello, I would like to ask about my total annual medical radiation exposure, which was 21 millisieverts in 2022. In August 2023, I underwent a dopamine scan, and today I had a CT scan of my head and neck. I would like to know if the 100 millisiever...


Dr. Wang Yifen Reply:
Hello, the necessity of X-ray radiation examinations is considered without limiting the radiation dose or the number of examinations. According to the International Commission on Radiological Protection (ICRP) report 103, doses below 100 millisieverts (including single or multipl...

[Read More] Is Your Medical Radiation Exposure Safe? Understanding Dosage Limits and Risks


Understanding Radiation Exposure from CT Scans and X-rays: Safety Concerns

Computed Tomography Radiation I underwent a head CT scan without contrast on September 23, 2021, a head MRI with contrast on March 16, 2022, and a sinus CT scan without contrast on February 8, 2024. I also had chest X-rays on February 8, 2024, May 27, 2022, August 31, 2022, Febru...


Dr. Zhang Zheng'ang Reply:
Hello: 1. The radiation dose for a sinus CT is approximately 0.7 mSv, and for a head CT, it is about 2.0 mSv. There is no need to consider excessive radiation in relation to medical necessity. 2. Yes. 3. There is no evidence to suggest that it would cause significant harm to the ...

[Read More] Understanding Radiation Exposure from CT Scans and X-rays: Safety Concerns


CT Scans for Infants: Concerns About Radiation and Safety

CT scan for a five-month-old infant? I took my child to the emergency room because he was exhibiting signs of possible seizures. The doctor performed a CT scan of the brain (the child is 5 months old) due to concerns about a potential head injury. I specifically informed the phys...


Dr. Wang Yifen Reply:
Hello, 1. A head computed tomography (CT) scan plays an irreplaceable role in the emergency department for patients with neurological dysfunction symptoms, as it quickly and accurately clarifies whether these symptoms are related to specific acute brain conditions, outperformin...

[Read More] CT Scans for Infants: Concerns About Radiation and Safety


Concerns About Repeated CT Scans in Young Children: Risks and Recommendations

A one-year and four-month-old child underwent four consecutive head CT scans? Hello, my son is currently one year and four months old. He slipped and hit the back of his head in the hotel bathroom. An hour later, he vomited twice, and we immediately took him to the emergency room...


Dr. Wang Yifen Reply:
Hello, performing imaging examinations on young children who are restless and unable to cooperate poses a significant challenge for the personnel conducting the tests. The radiation dose for an adult undergoing a single head computed tomography (CT) scan is approximately 2 millis...

[Read More] Concerns About Repeated CT Scans in Young Children: Risks and Recommendations


Does Frequent X-Ray Exposure Increase Cancer Risk? Understanding Radiation Effects

Will undergoing multiple radiographic examinations in a short period of time have an impact on the body? Hello Doctor, I experienced sudden abdominal discomfort last October, and over the past three months, I have undergone numerous tests, including X-rays, ultrasounds, and CT ...


Dr. Wang Yifen Reply:
Hello: Diagnostic X-ray examinations are classified as low-dose radiation imaging. According to the International Commission on Radiological Protection (ICRP) report 103, doses below 100 millisieverts (including single or multiple exposures) do not cause clinical functional impai...

[Read More] Does Frequent X-Ray Exposure Increase Cancer Risk? Understanding Radiation Effects


Understanding Radiation Exposure: 128-Slice vs. 640-Slice CT Scans

128-slice and 640-slice computed tomography (CT) scans? Hello, Doctor. I would like to inquire about the LDCT (Low-Dose Computed Tomography) chest scan. When using 128-slice and 640-slice CT, does the 640-slice CT emit less radiation than the 128-slice CT? The branch hospital I v...


Dr. Wang Yifen Reply:
Hello, the radiation exposure from a single LDCT (Low-Dose Computed Tomography) chest scan is approximately one-fifth that of a conventional CT scan. Both 128-slice and 640-slice CT scanners meet the specifications required by the National Health Administration for low-dose CT lu...

[Read More] Understanding Radiation Exposure: 128-Slice vs. 640-Slice CT Scans


Understanding Radiation Exposure and Its Impact on Blood Health

After undergoing a CT scan and X-ray, a blood test revealed abnormalities in the blood cells? Hello Doctor: Due to hematuria, a urologist performed several X-rays and one abdominal CT scan with contrast from March to December 2022. I noticed that the radiation dose recorded in th...


Dr. Wang Yifen Reply:
Hello, the American Association of Physicists in Medicine issued a public statement in 2011 stating that if a single "radiological examination" has a radiation dose of less than 50 millisieverts, and multiple "radiological examinations" are performed within a ...

[Read More] Understanding Radiation Exposure and Its Impact on Blood Health


Is Excessive Radiation Exposure a Concern with Multiple CT Scans?

Will the radiation dose from continuous CT scans exceed safe limits? Hello, doctor. My father was involved in a car accident on December 4th and was taken to the emergency room at Taipei Hospital. He sustained an injury to his leg but did not hit his head. However, the doctor ord...


Dr. Wang Yifen Reply:
Hello, diagnostic X-ray examinations are classified as low-dose radiation imaging. According to the International Commission on Radiological Protection (ICRP) report 103, doses below 100 millisieverts (including single or multiple exposures) do not cause clinical functional damag...

[Read More] Is Excessive Radiation Exposure a Concern with Multiple CT Scans?


Can Abdominal CT Scans Detect Breast Implants? Tips for Privacy

Can a CT scan of the abdomen detect breast implants? Hello, doctor. If I undergo a CT scan with and without contrast for the abdomen and pelvis, will the scan detect my breast implant, which contains a microchip? If it can be detected, how can I avoid this or communicate with the...


Dr. Wang Yifen Reply:
Hello, 1. The breast and abdominal organs overlap at the level of the diaphragm, making it unavoidable for the breast to be included in the imaging during positioning scans. The transverse section scan of the abdomen will overlap with part of the breast, while the pelvic cavity...

[Read More] Can Abdominal CT Scans Detect Breast Implants? Tips for Privacy


Understanding Radiation Dose in Chest CT Scans: A Comprehensive Guide

Radiation Dose Issues Hello, doctor. I would like to ask about the radiation doses for the following three types of chest CT scans: 1. Low-dose chest CT, 2. Standard chest CT without contrast, and 3. Chest CT with contrast. What are the approximate radiation doses in millisievert...


Dr. Wang Yifen Reply:
Hello, the radiation dose may vary slightly depending on the subject's body size, the scanning area, and the exposure time. According to the International Commission on Radiological Protection (ICRP) report 103, doses below 100 millisieverts (including single or multiple exp...

[Read More] Understanding Radiation Dose in Chest CT Scans: A Comprehensive Guide


Is My Radiation Exposure Too High? Understanding Safe Levels for 2022 and 2023

Radiation Issues Hello Doctor, in the year 2022, I accumulated a total of 20.828 millisieverts (as seen in the National Health Insurance Easy Access app), which includes many ultrasounds and X-rays. The 20.828 millisieverts only accounts for the examinations performed by doctors ...


Dr. Wang Yifen Reply:
Hello, ultrasound is a non-radiative examination and does not involve any radiation dose. Diagnostic X-rays and nuclear medicine dopamine brain scans are considered low-dose radiation examinations, which are reported to be safe according to the literature. When it comes to X-ray ...

[Read More] Is My Radiation Exposure Too High? Understanding Safe Levels for 2022 and 2023


Understanding the Impact of Cumulative Radiation Exposure from X-rays and CT Scans

Is the impact of radiation accumulation significant? Hello, doctor. I had chest X-rays in July, August, and on September 20th, and no issues were found. Since the cause of my chest pain and tightness remains unclear, I am now planning to undergo a low-dose computed tomography (CT...


Dr. Wang Yifen Reply:
Hello, a chest X-ray has a radiation dose of approximately 0.02 millisieverts, while a single low-dose computed tomography (CT) scan has a radiation dose of about 2 millisieverts. According to the International Commission on Radiological Protection (ICRP) report 103, doses below ...

[Read More] Understanding the Impact of Cumulative Radiation Exposure from X-rays and CT Scans


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