Sign-in to Ask A Doctor - 24x7
OR
Sign in with Google
How Many CT Scans Can Be Done In A Year?
Question: TO RADIOLOGY OR ONCOLOGY PROFESSIONAL:
With regards to the amount of radiation from full-body CT scan, I would like to know what is considered the safe number of CT Scans a person can have per year?
thank you.
With regards to the amount of radiation from full-body CT scan, I would like to know what is considered the safe number of CT Scans a person can have per year?
thank you.
Brief Answer:
No safe limit is there for CT scan and benefit to risk is to be considered
Detailed Answer:
Hi XXXX,
Thanks for writing in to us.
I have read through your query in detail.
Please find my observations below.
1. There is no safe limit for number of CT scans in a year. Each time you get a CT scan of any part of the body then there is radiation accumulated and this tells us the relative risk a person might have for development of a cancer. There is nothing called whole body CT scan, it is based on the part and purpose of examination.
2. The risk is calculated based on the number of CT scans, the part involved, the machine used, the technical factors and the patient variables like weight, age and gender. This is done using mathematical calculation.
3. Practically speaking one to two CT scans of a particular part in the body for adults done in a year does not matter much. However it does not mean that this should happen every year. In the case of a NHL patient on remission, it is essential to do CT scan regularly depending on stage and area involved for the benefit of the patient and to decide treatment.
Hope this answers your question. Please feel free to correct any oversight in my interpretation of your problems and discuss them in detail as per your requirements.
Hope your query is answered.
Do write back if you have any doubts.
Regards,
Dr.Vivek
No safe limit is there for CT scan and benefit to risk is to be considered
Detailed Answer:
Hi XXXX,
Thanks for writing in to us.
I have read through your query in detail.
Please find my observations below.
1. There is no safe limit for number of CT scans in a year. Each time you get a CT scan of any part of the body then there is radiation accumulated and this tells us the relative risk a person might have for development of a cancer. There is nothing called whole body CT scan, it is based on the part and purpose of examination.
2. The risk is calculated based on the number of CT scans, the part involved, the machine used, the technical factors and the patient variables like weight, age and gender. This is done using mathematical calculation.
3. Practically speaking one to two CT scans of a particular part in the body for adults done in a year does not matter much. However it does not mean that this should happen every year. In the case of a NHL patient on remission, it is essential to do CT scan regularly depending on stage and area involved for the benefit of the patient and to decide treatment.
Hope this answers your question. Please feel free to correct any oversight in my interpretation of your problems and discuss them in detail as per your requirements.
Hope your query is answered.
Do write back if you have any doubts.
Regards,
Dr.Vivek
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Dear Dr. XXXXXXX
Thank you for answering my question. Since May of 2014, I have undergone 4 CT scans - one was full body/from neck down and the other 3 were chest & abdomen. I now have the option to postpone my CT scan (scheduled for late this week) to later this year. What I am trying to determine is am I at risk of further cancer by having a 5th CT scan (full body, from neck down) now or would it make any difference pertaining to radiation risks, to postpone it? Your reply would be greatly appreciated.
thank you.
XXXXXXX
Thank you for answering my question. Since May of 2014, I have undergone 4 CT scans - one was full body/from neck down and the other 3 were chest & abdomen. I now have the option to postpone my CT scan (scheduled for late this week) to later this year. What I am trying to determine is am I at risk of further cancer by having a 5th CT scan (full body, from neck down) now or would it make any difference pertaining to radiation risks, to postpone it? Your reply would be greatly appreciated.
thank you.
XXXXXXX
Brief Answer:
The additional risk form the scheduled CT scan is 1 in 744 or 0.135 percent
Detailed Answer:
Hi XXXX,
Thanks for writing back with an update.
1. I have served in a cancer hospital as a radiologist for few years and have regularly come across patients like you.
2. The additional risk from having a CT scan neck downwards is approximately 27 mSv which will increase your relative risk for another cancer by 0.135 percent. In other words there is 99.865 percent chance that it will not affect you. The increased risk is not significant when comparing the total radiation accumulated from your previous CT scans.
3. Since you have an option, in my opinion as an expert, getting the CT scan done now might be done keeping in mind the last CT scan and disease status. If your last CT scan did not show disease in the neck, abdomen and pelvis then ultrasound scan neck, abdomen and pelvis might help right now and this can be followed by the CT scan abdomen and pelvis at a later time.
If you had any disease in the previous chest CT scan then doing another scan as scheduled later this week is required. Chest X ray has limited role in evaluating for small lymphnodes and might nor be completely informative.
In conclusion, if you had no sign of disease in the previous scan which was done in the last 3 then you might think of postponing the CT scan.
Hope your query is answered.
Do write back if you have any doubts.
Regards,
Dr.Vivek
The additional risk form the scheduled CT scan is 1 in 744 or 0.135 percent
Detailed Answer:
Hi XXXX,
Thanks for writing back with an update.
1. I have served in a cancer hospital as a radiologist for few years and have regularly come across patients like you.
2. The additional risk from having a CT scan neck downwards is approximately 27 mSv which will increase your relative risk for another cancer by 0.135 percent. In other words there is 99.865 percent chance that it will not affect you. The increased risk is not significant when comparing the total radiation accumulated from your previous CT scans.
3. Since you have an option, in my opinion as an expert, getting the CT scan done now might be done keeping in mind the last CT scan and disease status. If your last CT scan did not show disease in the neck, abdomen and pelvis then ultrasound scan neck, abdomen and pelvis might help right now and this can be followed by the CT scan abdomen and pelvis at a later time.
If you had any disease in the previous chest CT scan then doing another scan as scheduled later this week is required. Chest X ray has limited role in evaluating for small lymphnodes and might nor be completely informative.
In conclusion, if you had no sign of disease in the previous scan which was done in the last 3 then you might think of postponing the CT scan.
Hope your query is answered.
Do write back if you have any doubts.
Regards,
Dr.Vivek
Note: For further queries related to kidney problems Click here.
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Answered by
Get personalised answers from verified doctor in minutes across 80+ specialties
