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| MiniCAT™: Effective Patient Radiation Dose |
Unlike multi-purpose full-body CT scanners, MiniCAT™ has been specifically designed to scan the sinuses, skull base and temporal bones. Guided by the ALARA principle (As Low As Reasonably Achievable), MiniCAT™ has been optimized to provide high-quality images while minimizing the radiation dose to the patient.
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| MiniCAT™ Effective Dose* |
| Imaging Protocol |
Effective Dose |
| Temporal Bone |
0.14 mSv |
| Sinus 40 Second (Adult) |
0.17 mSv |
| Sinus 20 Second (Child) |
0.08 mSv |
| Sinus 10 Second (Follow-up) |
0.04 mSv |
| Scout View |
< .01 mSv |
*An additional benefit of shorter scans is a reduced likelihood of patient motion artifacts.
| Comparison to Other Modalities |
| Imaging Modality |
Effective Dose |
| Conventional CT Sinus Scan |
0.96 mSv |
| MiniCAT™ Sinus 40 Second |
0.17 mSv |
| Skull X-Ray * |
0.07 mSv |
| Chest X-Ray* |
0.02 mSv |
*Comparative figures taken from www.fda.gov/cdrh/ct/risks.html
MiniCAT™ Organ Dose |
Organ |
40 Second Sinus Scan
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Temporal Bone
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| Thyroid |
0.34 mGy |
0.24 mGy |
| Salivary Gland |
3.0 mGy |
3.0 mGy |
| Bone Marrow |
2.9 mGy |
1.6 mGy |
| Skin |
2.2 mGy |
2.5 mGy |
| Brain |
3.9 mGy |
5.1 mGy |
| Total Effective Dose |
0.17 mSv |
0.14 mSv |
Methods:
In calculating the effective dose, we closely followed the methodology suggested in ICRP 60 and Frederiksen et al. Twenty thermo-luminescent dosimeters (TLD) were placed in selected sites representing radio-sensitive tissues and organs in an anthropomorphic head phantom.2,3 The TLDs measured the absorbed dose to the thyroid, salivary gland, bone marrow, skin, and brain. The salivary gland was included in the effective dose calculations according to Frederiksen’s adaptation of the ICRP method3. The effective dose was calculated as the sum of the equivalent doses to each organ multiplied by that organ’s weighting factor.2,3 TLD measurements were not made for the 20 and 10 second scans. The values for these scans were approximated by linearly scaling the dose from the 40 second scan with the number of x-ray pulses used in each protocol.
- U.S. Food and Drug Administration, Center for Devices and Radiological Health. “What are the Radiation Risks from CT?” http://www.fda.gov/cdrh/ct/risks.html
January 28,2008
- Publication 60 of the International Commission on Radiological Protection (ICRP) “Radiation Protection. 1990 Recommendations of the International Commission on Radiological Protection,” Pergamon Press, Oxford 1990
- Frederiksen et al. (N.L. Frederiksen, B.W. Benson, and T.W. Sokolowski, “Effective dose and risk assessment from computed tomography of the maxillofacial complex,” Dentomaxillofacial Radiology, vol. 24, pp. 55-8, 1995)
- J. Alspaugh, E. Christodoulou, M. Goodsitt, J. Stayman, “Dose and Image Quality of Flat-Panel Detector Volume Computed Tomography for Sinus Imaging,” Medical Physics, vol. 34, pp. 26-34,2007
MiniCAT™ Dose Information: CTDI Values
To learn more about x-rays and the biological effects of x-rays, visit these sites:
The website of the American College of Radiology and Radiological Society of North America:
http://www.radiologyinfo.org/en/safety
U.S. Food and Drug Administration, Center for Radiological Health:
http://www.pueblo.gsa.gov/cic_text/health/fullbody-ctscan/rqu.htm
Conference of Radiation Control Directors, Inc.:
http://www.crcpd.org
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