Mean glandular dose

Short description: Amount of radiation absorbed by a breast during mammography

In mammography, mean glandular dose (MGD) is a quantity used to describe the absorbed dose of radiation to the breast. It is based on a measurement of air kerma and conversion factors. MGD can be calculated from measurements made with poly(methyl methacrylate) (PMMA) blocks. It is often used to compare typical doses to patients between different centres or internationally, and is the preferred measure of the potential risk from mammography.[1][2][3]

## Calculation

MGD can be calculated from a measured incident air kerma at the top of the breast, [math]\displaystyle{ K }[/math], as follows:[4]

[math]\displaystyle{ D=Kgcs }[/math]

[math]\displaystyle{ g }[/math] converts from incident air kerma to MGD, with a glandularity of 50%, based on breast thickness and HVL. [math]\displaystyle{ c }[/math] corrects for glandularity other than 50%, depending on the breast thickness and HVL, with two versions for ages 50–64 and 40–49. [math]\displaystyle{ s }[/math] corrects for the x-ray spectra in use with a table of target/filter combinations.[4][5]

## Applications

MGD is typically used to define limits on mammography exposures by national and international organisations such as the European Union and International Atomic Energy Agency, at <2.5 milligray (mGy) per exposure to a standard breast (4.5 cm PMMA).[6]

In routine quality assurance testing of mammographic equipment, MGD measurements for a range of effective breast thicknesses with PMMA, and from real patient exposures, is widely recommended.[2]

## References

1. ↑ Yaffe, Marlin J.; Barnes, Gary T.; Conway, Burton J.; Haus, Arthur G.; Karellas, Andrew; Kimme-Smith, Carolyn; Paul Lin, Pei-Jan; Mawdsley, Gordon et al. (1990). Equipment requirements and quality control for mammography. New York, NY: American Association of Physics in Medicine. ISBN 978-0-883188-07-1. https://www.aapm.org/pubs/reports/detail.asp?docid=28.
2. ↑ 2.0 2.1 Reis, Cláudia; Pascoal, Ana; Sakellaris, Taxiarchis; Koutalonis, Manthos (4 August 2013). "Quality assurance and quality control in mammography: a review of available guidance worldwide". Insights into Imaging 4 (5): 539–553. doi:10.1007/s13244-013-0269-1. PMID 23912879.
3. ↑ "Quality assurance guidelines for mammography including radiographic quality control" (in en). Public Health England. 2006. https://www.gov.uk/government/publications/breast-screening-quality-assurance-for-mammography-and-radiography.
4. ↑ 4.0 4.1 IAEA (2011). Quality assurance programme for digital mammography.. Vienna: International Atomic Energy Agency. ISBN 978-92-0-111410-5. http://www-pub.iaea.org/books/IAEABooks/8560/Quality-Assurance-Programme-for-Digital-Mammography.
5. ↑ Dance, D R; Skinner, C L; Young, K C; Beckett, J R; Kotre, C J (1 November 2000). "Additional factors for the estimation of mean glandular breast dose using the UK mammography dosimetry protocol". Physics in Medicine and Biology 45 (11): 3225–3240. doi:10.1088/0031-9155/45/11/308. PMID 11098900. Bibcode: 2000PMB....45.3225D.
6. ↑ Health & Consumer Protection, Directorate-General (2006). Perry, N. ed. European guidelines for quality assurance in breast cancer screening and diagnosis (4th ed.). Luxembourg: Office for Official Publ. of the Europ. Communities. p. 203. ISBN 978-92-79-01258-7. https://archive.org/details/europeanguidelin0000euro/page/203.

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Radiation protection

Main articles|

* Background radiation
* Dosimetry
* Health physics
* Ionizing radiation
* Internal dosimetry
* Radioactive contamination
* Radioactive sources
* Radiobiology

Measurement
quantities & units|

* Absorbed dose
* Becquerel
* Committed dose
* Computed tomography dose index
* Counts per minute
* Effective dose
* Equivalent dose
* Gray
* Mean glandular dose
* Monitor unit
* Rad
* Roentgen
* Rem
* Sievert

Instruments and
measurement techniques|

* Airborne radioactive particulate monitoring
* Dosimeter
* Geiger counter
* Ion chamber
* Scintillation counter
* Proportional counter

* Radiation monitoring
* Semiconductor detector
* Survey meter
* Whole-body counting

Protection techniques|

* Lead shielding
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Organisations|

* Euratom
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Regulation|

* IRR (UK)
* NRC (USA)
* ONR (UK)
* Radiation Protection Convention, 1960

Radiation effects|

* Acute radiation syndrome
* Radiation-induced cancer

See also: the categories Medical physics, Radiation effects, Radioactivity, Radiobiology, and Radiation protection.

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