Optimum x-ray spectra for mammography: choice of K-edge filters for tungsten anode tubes

McDonagh, C P; Leake, Jason; Beaman, S A

doi:10.1088/0031-9155/29/3/004

Cited by 12 publications

(11 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The calculated optimum mean x-ray energies are in the range of 15-18 keV and 21.5-25 keV for a 2.5 and 8 cm thick breast, respectively. [17][18][19][20][21][22] It can be shown that if polychromatic radiation with a fixed photon energy distribution is used, such as that produced by a standard Mo x-ray tube, the photon fluence that is in the optimum band for a given breast thickness decreases dramatically for thicker breasts; e.g., for the Mo/0.03 mm Mo system, it decreases from 57% to 6% for 2.5 and 8 cm breast thicknesses, respectively.…”

Section: B the X-ray Beam Qualitymentioning

confidence: 99%

Laser‐based microfocused x‐ray source for mammography: Feasibility study

et al. 1997

View full text Add to dashboard Cite

A laser-produced plasma (LPP) x-ray source with possible application in mammography was created by focusing a laser beam on a Mo target. A Table-Top-Terawatt (TTT) laser operating at 1 J energy per pulse was employed. A dual pulse technique was used. Maximum energy transfer (approximately 10%) from laser light to hot electrons was reached at a 150 ps delay between pulses and the conversion efficiency (hard x-ray yield/laser energy input) was approximately 2 x 10(-4). The created LPP x-ray source is characterized by a very small focal spot size (tens of microns), Gaussian brightness distribution, and a very short pulse duration (a few ps). The spectral distribution of the generated x rays was measured. Images of the focal spot, using a pinhole camera, and images of a resolution pattern and a mammographic phantom were obtained. The LPP focal spot modulation transfer function for different magnification factors was calculated. We have shown that the LPP source in conjunction with a spherically bent, high throughput, crystal monochromator in a fixed-exit Rowland circle configuration can be used to created a narrow band tunable mammography system. Tunability to a specific patient breast tissue thickness and density would allow one to significantly improve contrast and resolution (exceeding 20 lp/mm) while lowering the exposure up to 50% for thicker breasts. The prospects for the LPP x-ray source for mammographic application are discussed.

show abstract

Section: B the X-ray Beam Qualitymentioning

confidence: 99%

Laser‐based microfocused x‐ray source for mammography: Feasibility study

et al. 1997

View full text Add to dashboard Cite

show abstract

“…Recently, it has been suggested that x-ray tubes with tungsten anodes used with palladium filters would give images comparable to molybdenum tubes (7,8,30). An example of a primary mammographic spectrum at 30 kYp with a tungsten anode is also shown in Fig.…”

Section: Basic Considerationsmentioning

confidence: 99%

“…Fig. 13 shows that the scatter to primary ratio increases with increasing tube potential within the potential interval investigated (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36) when no grid is employed. Using a grid, the scatter to primary ratio is more or less constant with tube potential.…”

Section: Basic Considerationsmentioning

confidence: 99%

See 1 more Smart Citation

Image Quality in Mammography with Special Reference to Anti-Scatter Grids and the Magnification Technique

Nielsen¹,

Fagerberg²

1986

Acta Radiologica. Diagnosis

View full text Add to dashboard Cite

Some of the parameters determining image quality in mammography are analyzed: the effects of primary photon spectra, focal spot size and screen-film systems on spatial resolution are discussed as are scattered radiation, development temperature and absorbed dose. The parameters limiting spatial resolution and contrast are evaluated for the standard and magnification techniques. Methods of reducing scattered radiation to improve contrast are evaluated. Scatter to primary ratios for different scatter reducing methods are compared, using the physical quantity energy imparted. For the standard technique the spatial resolution has been found to be limited by the fluorescent screen. With magnification technique the focal spot is the weakest link for the spatial resolution. The contrast is mainly set by the amount of scatter using the standard technique considering the use of a low tube potential (approximately 25 kVp). Using the magnification technique the amount of scatter is so small, that the tube potential is the limiting factor. We have found the optimized standard mammographic technique to be achieved under the following conditions: 25 kVp, 0.3 to 0.6 mm focal spot, film-focus distance 500 mm, anti-scatter grid, developing temperature 36 to 38 degrees C and 4 minutes total processing time with the screen-film system we have used. In magnification technique an air gap of at least 20 mm is desired. With an FFD of about 500 mm this will give a magnification ratio of 1.8 to 2.0 and a 0.1 mm X 0.1 mm focus spot is mandatory. With this technique, it is necessary to use a faster screen-film system than that used in standard mammography.

show abstract

“…Por outro lado, o espectro de raios X emitido por um tubo com anodo de tungstênio, na região de energia utilizada em mamografia,é formado principalmente por radiação contínua (Bremsstrahlung) (Figura 2.2). Para que o espectro produzido por um tubo de raios X com anodo de tungstênio possa ser utilizado em mamografiaé necessário utilizar filtros com bordas de absorção (K-edge) em energias apropriadas a fim de subtrair do espectro a parcela de fótons acima de uma dada energia que degrada a imagem e a parcela da radiação de baixa energia que aumenta a dose de radiação recebida pela paciente e que não contribui para a formação da imagem [47][48][49][50][51][52].…”

Section: Caracterização Dos Sistemas De Raios X 221 Adaptação Do Siunclassified

"Espectrometria de raios X em mamografia aplicada à proteção radiológica"

Künzel¹

View full text Add to dashboard Cite

Optimum x-ray spectra for mammography: choice of K-edge filters for tungsten anode tubes

Cited by 12 publications

References 2 publications

Laser‐based microfocused x‐ray source for mammography: Feasibility study

Laser‐based microfocused x‐ray source for mammography: Feasibility study

Image Quality in Mammography with Special Reference to Anti-Scatter Grids and the Magnification Technique

"Espectrometria de raios X em mamografia aplicada à proteção radiológica"

Contact Info

Product

Resources

About