Resolution in radiographic magnification

Wagner, Louis K.; Cohen, Gerald; Wong, W. H.; Amtey, Sharad R.

doi:10.1118/1.594962

Cited by 3 publications

(2 citation statements)

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“…The characteristics of a system can be expressed in terms of line spread function (LSF), modulation transfer function (MTF) and Wiener spectra but no single quantity provides an adequate index of image quality. For example images of small objects with high contrast are less affected by noise than larger objects with low contrast, but the former are more sensitive to MTF than the latter (Haus et a1 1977, Wagner 1977, NRCP 1980, Wagner et al 1981. Nevertheless, it is informative to analyse the resolving power of a system in terms of the MTF of the receptor and the geometric unsharpness of the imaging system.…”

Section: Image Receptors and Imaging Systemsmentioning

confidence: 99%

Methods of breast imaging

Jones¹

1982

pmb

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Section: Image Receptors and Imaging Systemsmentioning

confidence: 99%

Methods of breast imaging

Jones¹

1982

pmb

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“…4,5 Magnification and its effects on image quality have been studied in conventional radiography. 6,7,8 In general, magnification improves visibility of small, low contrast objects. As the magnification increases, the effective noise in the image detector is reduced improving the signal-to-noise ratio, and visibility of small structures improves.…”

Section: Introductionmentioning

confidence: 99%

How does magnification affect image quality and patient dose in digital subtraction angiography?

Gkanatsios

Huda

Peters

2001

Medical Imaging 2001: Physics of Medical Imaging

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Digital subtraction angiography (DSA) images were obtained of a phantom containing 1 mm diameter vessels. The iodine concentrations ranged from 5 to 50 mg/cc, which permitted the determination of the detection threshold concentration of iodine. The source to image receptor distance was 105 cm, and image magnification was varied between 1.15 and 2.0. One experiment was performed at an input exposure of 1 µGy per frame, and a second experiment was performed at 4 µGy per frame. Surface (skin) doses were measured using an ionization chamber, and the corresponding values of energy imparted were determined from the exposure area product. Increasing the radiation exposure by a factor of four reduced the threshold iodine concentration by ~30%. The average detection threshold iodine concentration for a magnification of 1.15 was 13.6 mg/cc. Detection performance improved linearly with magnification, with an average value of 7.4 mg/cc at a magnification of 2.0. Values of energy imparted were essentially independent of image magnification, whereas surface doses increased by a factor of four when image magnification was increased from 1.15 to 2.0. Magnification offers improved imaging performance at no additional patient risk provided that surface doses do not exceed the dose threshold for deterministic effects such as skin burns and epilation.

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