Radiation
Copyright 2009
=
Tthe average radiation dose of a CT scan to the lungs is 16 mGy, 14 mGy to the abdomen and 10 mGy to the bone barrow (Brenner). The average dose is about 12 mSv (13). The annual natural background radiation dose is 3 mSv. Therefore the radiation dose received from a CT scan is much higher than the annual background radiation dose. Brenner et al. compare these values with the data obtained from study groups of atomic bomb survivors, which showed a statistical increase in cancer risks after radiation exposure. The atomic bomb individuals were exposed to a dosage amount between 5 and 100 mSv (13). Based on this data and the known radiation dose from CT scans, they conclude that there are valid cancer risks associated with CT scan radiation.
Effective Radiation Dosage, Measured in MilliSieverts (mSv)
|
Average Background Dose – U.S |
3.6 mSv/year |
|
Three-Hour Commercial Airline Flight |
0.015 mSv |
|
Pa & Lateral Chest X-Ray |
0.05 mSv |
|
Head CT Examination |
1-2 mSv |
|
Chest CT |
5-7 mSv |
|
Abdomen & Pelvis CT |
6-8 mSv |
|
Selective Diagnostic Coronary Angiography |
3-6 mSv |
|
Diagnostic Coronary Angiography with Intervention |
6-30 mSv |
|
Nuclear Medicine Stress Test |
|
|
SPECT Thallium |
25.3 mSv |
|
SPECT Sestamibi |
12.2 mSv |
|
Coronary CT Angiography |
|
|
Retrospective CCTA |
13 mSv |
|
Retrospective EKG-Modulated CCTA |
8-9 mSv |
|
Prospective “Step-and-Shoot” CCTA |
2-3 mSv |
|
For this procedure:
|
Your effective radiation dose is: | Comparable to natural background radiation for: |
|---|---|---|
| Abdominal region: | ||
| Computed Tomography (CT)-Abdomen and Pelvis |
10 mSv
|
3 years
|
| Computed Tomography (CT)-Body |
10 mSv
|
3 years
|
| Computed Tomography (CT)-Colonography |
10 mSv
|
3 years
|
| Intravenous Pyelogram (IVP) |
3 mSv
|
1 year
|
| Radiography-Lower GI Tract |
8 mSv
|
3 years
|
| Radiography-Upper GI Tract |
6 mSv
|
2 years
|
| Bone: | ||
| Radiography-Spine |
1.5 mSv
|
6 months
|
| Radiography-Extremity |
0.001 mSv
|
Less than 1 day
|
| Central Nervous system: | ||
| Computed Tomography (CT)-Head |
2 mSv
|
8 months
|
| Computed Tomography (CT)-Spine |
6 mSv
|
2 years
|
| Myelography |
4 mSv
|
16 months
|
| Chest: | ||
| Computed Tomography (CT)-Chest |
7 mSv
|
2 years
|
| Radiography-Chest |
0.1 mSv
|
10 days
|
| Children’s imaging: | ||
| Voiding Cystourethrogram |
5-10 yr. old: 1.6 mSv
|
6 months
|
|
Infant: 0.8 mSv
|
3 months
|
|
| Face and neck: | ||
| Computed Tomography (CT)-Sinuses |
0.6 mSv
|
2 months
|
| Heart: | ||
| Cardiac CT for Calcium Scoring |
3 mSv
|
1 year
|
| Men’s Imaging: | ||
| Bone Densitometry (DEXA) |
0.001 mSv
|
Less than 1 day
|
| Women’s Imaging: | ||
| Bone Densitometry (DEXA) |
0.001 mSv
|
Less than 1 day
|
| Galactography |
0.7 mSv
|
3 months
|
| Hysterosalpingography |
1 mSv
|
4 months
|
| Mammography |
0.7 mSv
|
3 months
|
Reference Safety in Medical Imaging from American College of Radiology
Boone JM. Multidetector CT: Opportunities, challenges, and concerns associated with scanners with 64 or more detector rows. Radiology 2006;241:334-337.
Brenner D and Elliston C. Estimated Radiation Risks Potentially Associated with Full-Body CT Screening. Radiology 2004; 232:735-738
Herzog, B , Wyss, C A, Husmann, L, Gaemperli, O, Valenta, I, Treyer, C Landmesser, U, and Kaufmann P A First head-to-head comparison of effective radiation dose from low-dose 64-slice CT with prospective ECG-triggering versus invasive coronary angiography Heart October 15, 2009 95:1656-1661
Perisinakis K, Theocharopoulos N, Karkavitsas N, Damilakis J. Patient effective radiation dose and associated risk from transmission scans using 153Gd line sources in cardiac SPECT studies. Health Phys 2002; 83:66-74.