J Korean Med Sci.  2016 Feb;31(Suppl 1):S45-S54. 10.3346/jkms.2016.31.S1.S45.

Patient Dose Management: Focus on Practical Actions

• Park MY
• Jung SE

• KMID: 2363380
• DOI: http://doi.org/10.3346/jkms.2016.31.S1.S45

Abstract

Medical radiation is a very important part of modern medicine, and should be only used when needed and optimized. Justification and optimization of radiation examinations must be performed. The first step of reduction of medical exposure is to know the radiation dose in currently performed examinations. This review covers radiation units, how various imaging modalities report dose, and the current status of radiation dose reports and legislation. Also, practical tips that can be applied to clinical practice are introduced. Afterwards, the importance of radiology exposure related education is emphasized and the current status of education for medical personal and the public is explained, and appropriate education strategies are suggested. Commonly asked radiation dose related example questions and answers are provided in detail to allow medical personnel to answer patients. Lastly, we talk about computerized programs that can be used in medical facilities for managing patient dose. While patient dose monitoring and management should be used to decrease and optimize overall radiation dose, it should not be used to assess individual cancer risk. One must always remember that medically justified examinations should always be performed, and unneeded examinations should be avoided in the first place.

Keyword

Radiation, Ionizing; Medical Exposure; Radiation Protection; Optimization; Justification

MeSH Terms

Humans
*Radiation Dosage
Radiation Protection
Radiation, Ionizing
Tomography, X-Ray Computed

Figure

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  Fig. 1 An example of DICOM header of a chest X-ray that includes kVp, mAsm and DAP. The DICOM header shows a kVp value of 117 and DAP of 0.433.

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  Fig. 2 Dose report for a modern fluoroscopy machine. During transarterial chemoembolization, 9 flurosocopic sessions and one cone beam CT scan were performed. Total fluoroscopic time is reported as 10 minutes 53 seconds with a DAP of 15,260 μGycm2, and 10 spot images with a DAP of 40,040 μGycm2.

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  Fig. 3 Separate installed internal DAP meter (A) and display screen (B). There are DAP meters that can be installed in the fluoroscopy machine internally to monitor dose.

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  Fig. 4 An example dose report from a three phase liver CT performed on a GE Discovery CT750HD CT machine. GE machines displace the scan type (helical or axial) and scan length. Series 1 is a scanogram, series 2 is a precontrast examination, series 200 is bolus tracking before initiating contrast scan, and series 3 is the three contrast phase examinations (arterial, portal, delayed). Portal phase scan lower range is the lower pelvic cavity while other phases included only the upper abdomen. Total DLP is 822.46 mGy × cm. When using and multiplying a weighting factor (k factor) of 0.015 to estimate estimated dose, the estimated dose is about 12.3 mSv.

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  Fig. 5 An example dose report from a three phase liver CT performed on a Siemens SOMATOM Definite AS+ CT machine. CTDIvol and DLP are shown. Siemens machines also report tube potential (kV), tube current (mAs), reference tube current (mAs) when using automated dose modulation, and X-ray time per rotation (TI). The size of phantoms used for calculations are also displayed (L for large 32 cm, and S for small 16 cm). Automated tube current (kVp) modulation was used and precontrast, arterial, and delayed phase images used an 80 kVp, while portal phase uses a 100 kVp. Portal phase scan lower range is the lower pelvic cavity while other phases included only the upper abdomen. Total DLP is 709 mGy × cm. When using and multiplying a weighting factor (k factor) of 0.015 to estimate estimated dose, the estimated dose is about 10.6 mSv.

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