Children's Heterogeneous Phantoms and Their Application in Röntgenology

Varchenya, V.; Gubatova, D.Ya.; Sidorin, V.P.; Kalnitsky, S. A.

doi:10.1093/oxfordjournals.rpd.a081905

Cited by 4 publications

(4 citation statements)

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“…Specifically then, given ͑1͒ the problems in maintaining CTDI as a relevant dose index, ͑2͒ the availability of MOSFET ͑or TLD, if preferred͒ dosimeters that are very small, sensitive, and convenient to use, and ͑3͒ the commercial availability of heterogeneous whole-body anthropomorphic phantoms such as the ATOM ® phantoms 21,22 and the Alderson radiation therapy phantoms, 23,24 perhaps it is time to consider retiring ͑with honor͒ the CTDI-inhomogeneousphantoms approach to CT QA/DO. One might envisage CTDI measurements being replaced by direct simultaneous MOSFET or TLD measurements of doses at locations in appropriate organs of a full-body anthropomorphic phantom, perhaps appropriate subsets of stomach, colon, breast, lung, gonads, thyroid, bladder, esophagus, liver, brain, and relevant bone marrow.…”

Section: Letter To the Editormentioning

confidence: 99%

“…One might also wish to utilize a pair of anthropomorphic phantoms, one adult and one pediatric. 22,26 On the technical side, the energy dependence of the MOSFET or TLD dosimeters would need to be considered-as is also the case for a CTDI ion chamber. It would also be desirable to establish a benchmark system for extrapolating direct dosimetric measurements to different, but similar, scanner settings; by analogy with current techniques, 10,11 one could envisage this being done based on standardized sets of Monte Carlo simulations in voxelized computational versions of the physical phantoms.…”

Section: Letter To the Editormentioning

confidence: 99%

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Is it time to retire the CTDI for CT quality assurance and dose optimization?

Brenner

2005

Medical Physics

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Section: Letter To the Editormentioning

confidence: 99%

Section: Letter To the Editormentioning

confidence: 99%

Is it time to retire the CTDI for CT quality assurance and dose optimization?

Brenner

2005

Medical Physics

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“…This concept of mimicking living tissue for radiation biology experiments is well established. Numerous anthropomorphic phantoms, such as the RANDO or ART models made by Alderson Radiation Therapy (Radiology Support Devices, Long Beach, CA) or the ATOM Dosimetry Phantom (Computerized Imaging Reference Systems, Norfolk, VA) are commercially available for characterizing imaging systems, quality assurance of radiation therapy, and research purposes (Shepherd et al , 1997; Gubatova et al , 1989; Varchenya et al , 1993). These human phantoms are manufactured from a variety of plastics and resins to simulate soft tissue, bone, lung, and brain; they are constructed in slices and have dosimeter locations in multiple positions within the phantom organs.…”

Section: Introductionmentioning

confidence: 99%

Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies

et al. 2015

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We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions.

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“…Such small catheters are often difficult to visualize on radiographs, and accurate positioning is critical. 9 An anthropomorphic neonatal phantom (ATOM Ltd., Riga, Latvia) 10 with a 1-French catheter taped to its surface was imaged in a conventional geometry with a focus-to-receptor distance of 90 cm, then in a phase-contrast geometry with d 1 5 2.5 m and d 2 5 2.5 m. Clinically realistic exposure factors of 60 kVp and 2 mAs at a focus-skin distance of 80 cm were used for the conventional geometry, resulting in a measured entrance skin dose of 87 mGy. In the phase-contrast geometry, 60 kVp was maintained and the mAs scaled up to give a measured entrance surface dose of 91 mGy at the much greater focus to skin distance.…”

Section: Phase-contrast Imagingmentioning

confidence: 99%

Phase-contrast and magnification radiography at diagnostic X-ray energies using a pseudo-microfocus X-ray source

Kotre

Robson²

2014

BJR

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Cite this article as: Kotre CJ, Robson KJ. Phase-contrast and magnification radiography at diagnostic X-ray energies using a pseudo-microfocus X-ray source. Br J Radiol 2014;87:20130734. FULL PAPER Phase-contrast and magnification radiography at diagnostic X-ray energies using a pseudo-microfocus X-ray source 1 C J KOTRE, PhD Objective: To investigate the use of conventional diagnostic X-ray tubes for applications in which specialist microfocus sources are normally required. Methods: A conventional diagnostic X-ray tube was used in conjunction with a range of apertures to investigate improvements in spatial resolution using a line-pairs test object. Phase-contrast effects were investigated by varying source-to-object and object-to-receptor distances using a 2-French catheter as a clinically realistic test object.Results: For magnification radiography using a computed radiography receptor and conventional X-ray tube with a 1-mm nominal focus size, the limiting spatial resolution was improved from 3.55 line-pairs per millimetre, for a conventional contact image, to 5.6 line-pairs per millimetre, for a 32 magnified view with a 250-mm aperture. For inline phase-contrast radiography, phase contrast enhancement of a 2-French catheter was demonstrated, and the expected trends with variations in source-toobject and object-to-receptor distances were found.Images of a neonatal phantom demonstrated a subtle improvement in visibility of a superimposed 1-French catheter simulating a percutaneously inserted central catheter for no increase in patient radiation dose. Conclusion: Spatial resolution improvement and visible phase contrast can be produced in clinically relevant objects using a pseudo-microfocus geometry at X-ray energies in the normal diagnostic range, using conventional diagnostic X-ray tubes and image receptors. The disadvantages of the proposal are the large distances required to produce phase contrast and limitations imposed by the resulting tube loading. Advances in knowledge:It is possible to use conventional diagnostic X-ray equipment in applications that normally require microfocus X-ray sources. This presents some possibilities for clinical applications.The rotating anode X-ray tube is by far the most common X-ray source used in diagnostic radiology. The engineering compromises inherent in the bevelled tungsten-rhenium rotating anode design deliver a relatively high radiation output with an adequate field coverage and heat dissipation for most radiology work, combined with an X-ray focus size that does not lead to visible geometric unsharpness in normal use. A common nominal X-ray focus size for general radiography is 1.0 or 1.2 mm with a switchable 0.6-mm fine focus. Although these sizes cover normal medical radiographic imaging requirements, there are specialist applications where a microfocus X-ray source is required. Commercial laboratory microfocus X-ray units commonly operate at relatively low energies and at low output, the output being restricted by the heat capacity of the typically station...

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Children's Heterogeneous Phantoms and Their Application in Röntgenology

Cited by 4 publications

References 0 publications

Is it time to retire the CTDI for CT quality assurance and dose optimization?

Is it time to retire the CTDI for CT quality assurance and dose optimization?

Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies

Phase-contrast and magnification radiography at diagnostic X-ray energies using a pseudo-microfocus X-ray source

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