**7. References**


Image Quality Requirements for Digital Mammography in Breast Cancer Screening 131

IAEA. International Atomic Energy Agency. (2007). Dosimetry in Diagnostic Radiology: An

IAEA. International Atomic Energy Agency. (2011). Quality Assurance Programme For Digital

ICRU. International Commission on Radiation Units and Measurements. (2005). Patient

ICRU. International Commission on Radiation Units and Measurements. (2009).

IPEM. Institute of Physical and Engineering in Medicine. (1989). The commissioning and

Lewin JM, D'Orsi CJ, Hendrick RE. 2004. Digital mammography. *Radiol Clin N Am.* 42:871 –

Karellas A and Giger M L. 2004. Advances in Breast Imaging: Physics, Technology, and

Kruger R L and Schueler B A. (2001). A survey of clinical factors and patient dose in

Leitz, W and Jönsson H (2001). Patientdoser från röntgenundersökningar i Sverige*.* SSI

Maria S. Nogueira; Luciana de J. S. Pinheiro; Danille S. Gomes, William José de Castro, Katiane

Muller S. (1997). Full-field digital mammography designed as a complete system. *European* 

NCRP. National Council on Radiation Protection and Measurements. (1986). Mammography –

NCRP. National Council on Radiation Protection and Measurments. (2004). A Guide to

NG, KH, Jamal, N, Dewerd, L. (2006). Global quality control perspective for the physical on

mammography. *Med. Phys.* 28:1449-1454. ISSN 0094-2405

*Journal of Radiology* 31: 25–34. ISSN: 0720-048X

Rapport 2001:1. *Swedish Radiation Protection Authority*. (Sweden)

*Measurements*, Bethesda, Maryland, USA. ISBN-10: 0913392790

*Radiat Prot Dosimetry* 121(4): 445-451. ISSN 1742-3406

*Roentgenol* 194:362–369. ISSN: 1546-3141

*Agency*, (Vienna, Austria). ISBN 978–92–0–111410–5

*Energy Agency*, Vienna ; Austria

University Press, Oxford, UK

University Press, Oxford, UK

903613 21 3, York, UK

884. ISSN 1557-8275

ISSN 1361-6560

Brazil

929600-84-3

Radiology Imaging Network Digital Mammographic Imaging Screening Trial. *Am. J.* 

International Code of Practice, Technical Reports Series No. 457. *International Atomic* 

Mammography. IAEA Human Health Series No 17. *International Atomic Energy* 

Dosimetry for X Rays Used in Medical Imaging, ICRU Report 74. *J. ICRU*. 5(2),

Mammography– Assessment of Image Quality. ICRU Report 82*. J. ICRU* 9(2),

routine testing of mammographic x-ray systems. Report 59 1st ed. *IPEM,* ISBN : 1

Clinical Applications. *The Radiological Society of North America* (RSNA 2004), Presented at the 90th Scientific Assembly and Annual Meeting of the Radiological Society of North America, November 28–December 3, 2004, Chicago, USA. ISSN 0271-5333 Klein R, Aichinger H, Dierker J, Jansen J T M, Joite-Barfuss S, Säbel M, Schulz-Wendtland R

and Zoetelief J. (1997). Determination of average glandular dose with modern mammography units for two large groups of patients*. Phys Med Biol*. 42:651–671.

Costa; Marcio A. de Oliveira; Margarita Chevalier del Rio (2011). Development of methodology for estimating thickness of compressed breast in mammography. *International Conference on Medical Physics ICMP*, April 17-20, 2011. Porto Alegre,

A User's Guide. NCRP Report 85. *National Council on Radiation Protection and* 

Mammography and Other Breast Imaging Procedures, NCRP Report 149. *National Council on Radiation Protection and Measurements*. Bethesda, Maryland, USA. ISBN 0-

technical aspects of screen-film mammography-image quality and radiation dose.


Brazil Ministry of Health. Report nb. 453 of June 1, (june 1998). Guidelines for Radiological

Burch A, and Law J. (1995). A method for estimating compressed breast thickness during

CEC. European Commission. (1996). European Protocol on Dosimetry in Mammography,

CEC. European Commission. European Guidelines for Quality Assurance in Mammography

Chevalier M, Morán P, Pombar M, Lobato R, Vañó E. (1998). Breast Dose Measurements on a

Chevalier and Torres R. (2010). Mamográfica digital. Rev Fis Med 11(1):11-26 (SEFM, Madrid) Dance DR. (1990). Monte-Carlo calculation of conversion factors for the estimation of mean

Dance DR, Skinner CL, Young KC, Beckett J R and Kotre CJ. (2000). Additional factors for the

Dance DR., Thilander Klang A, Sandborg M, et al. (2000). Influence of anode/filter material

Duffy SW, Tabar L, Chen THH, Smith RA, Holmberg L, Jonsson H, Lenner P, Nyström L, and

Geise RA, and Palchevsky A. (1996). Composition of mammographic phantom materials.

Riabi HA, Mehnati P, Mesbahi A. (2010). Evaluation of mean glandular dose in a full-field

Hammerstein GR, Miller DW, White DR, Masterson ME,Woodard HQ and Laughlin JS. (1979). Absorbed radiation dose in mammography*. Radiology*. 130, 485–491. ISSN 1527-1315 Hellquist BN, Duffy SW, Abdsaleh S, Björneld L, Bordás P, Tabár L, Viták B, Zackrisson S,

Hendrick RE, Pisano ED, Averbukh A, Moran C, Berns EA, Yaffe MJ, Herman B, Acharyya S,

glandular breast dose. *Phys Med Biol*. 35: 1211–1220. ISSN 1361-6560

mammography. *Br J Radiol*. 68: 394–399. ISSN: 1748-880X

Publications of the European Communities, Luxembourg

protocol. *Phys Med Biol*. 45: 3225–3240. ISSN 1361-6560

Press, Brasília, Jun 2, 1998.

&co\_obra=181971)

1742-3406

Epidemiol. Biomarkers Prev 15: 45–51

*Radiology*. 198: 347–350. ISSN 1527-1315

714–722. doi: 10.1002/cncr. 25650

European Communities, Luxembourg

(1998) 80 (1-3): 187 – 190. ISSN 1742-3406

Protection in Medical and Odontological Radiodiagnostic. *Ministry of Health*, Official

Report EUR 16263. *European Commission.* Office for Official Publications of the

Screening. (2006). Report EUR 14821 4th ed. *European Commission.* Office for Official

Large Group of Patients: Results from a Four Years Period. *Radiat Prot Dosimetry.* 

estimation of mean glandular breast dose using the UK mammography dosimetry

and tube potential on contrast, signal-to-noise ratio and average absorbed dose in mammography: a Montecarlo study. *Br J Radiol* 73: 1056-1067. ISSN: 1748-880X Dantas MVA and Nogueira MS. (2010). Dose glandular e controle de qualidade da imagem em

serviços de mamografia com sistema de radiografia computadorizada. Comissão Nacional de Energia Nuclear, *Centro de Desenvolvimento Da Tecnologia Nuclear*, Programa de Pós-Graduação em Ciência e Tecnologia das Radiações Minerais e Materiais, Belo Horizonte, Brasil, 2010. (Available from, http://www.dominiopublico.gov.br/pesquisa/DetalheObraForm.do?select\_action=

Törnberg S. 2006. Reduction in breast cancer mortality from organized service screening with mammography:1.Further consideration with extended data. Cancer

digital mammography unit in Tabriz, Iran. *Radiat Prot Dosimetry* 142, 22-227. ISSN

Nyström L, and Jonsson H, (2010) Effectiveness of Population-Based Service Screening with Mammography for Women Ages 40 to 49 Years. Evaluation of the Swedish Mammography Screening in Young Women (SCRY) Cohort. *Cancer* 117:

and Gatsonis C. 2010. Comparison of Acquisition Parameters and Breast Dose in Digital Mammography and Screen-Film Mammography in the American College of Radiology Imaging Network Digital Mammographic Imaging Screening Trial. *Am. J. Roentgenol* 194:362–369. ISSN: 1546-3141


**6** 

*USA* 

George Zentai

**Contrast Enhancement in Mammography** 

To understand how we can optimize the spectrum of an X-ray beam to obtain the maximum contrast using the minimum dose for a given x-ray exam we need to know a little about how the X-rays are generated, how an x-ray tube works, how the energy spectrum of the output X-ray beam will look and how the X-rays interact with the human body and with the

A general X-ray tube has two electrodes, the cathode and the anode, with a high voltage applied between them. Electrons are generated at the cathode. After the electrons are emitted from the cathode they are accelerated by the high voltage toward the anode (positive) electrode. The high speed electrons hitting the anode material then generate invisible radiation i.e. X-rays. The energy spectrum of the output X-rays is dependent on the anode-cathode voltage difference and on the material of the anode and is measured in electronvolts. The energy spectrum is a so called Brehmstrahlung radiation meaning that it is continuous over a wide range of energies and has more photons emitted at the lowest energies. The photon flux decreases to zero at the anode-cathode voltage difference level.

When the Brehmstrahlung radiation of the X-ray beam passes into the human body, some photons are absorbed while others pass through. The ones that have passed through are available for imaging. Because the absorption of the human body is higher at lower energy X-rays, the beam exiting the body has a higher average energy than the beam had when it entered the body. This effect is called beam hardening and it causes a decrease in the contrast of images and difficulties in CT reconstruction. Furthermore, the dose the patient receives from the very low energy X-rays serves no purpose; it does not contribute to the

Figure 1 demonstrates the difference between input and exit X-ray beams showing that the very low energy X-rays do not penetrate the human body at all and only add extra (unwanted) dose to the patient (Sutton 2009). Three cases are shown in the figure. The original input beam, an 80kVp X-ray beam from a W anode filtered through a 2 mm Al filter, is shown in blue and has the highest photon flux and widest energy spectrum. The red series shows the energy of the beam after having passed through simulated soft tissue (150 mm soft tissue and 50 mm water). This exit beam shows that only X-ray photons with >25keV energy will contribute to the image. The green series shows the energy of the beam

**1. Introduction** 

final image in any way.

imager.

**Imaging Including K Edge Filtering** 

*Ginzton Technology Center of Varian Medical Systems* 

