Proton Computed Tomography of Human Specimens

Hanson, Kenneth M.; Bradbury, J. N.; Koeppe, Robert A.; Macek, R.; Machen, Donald R.; Morgado, Rosbel; Paciotti, M. A.; Sandford, Scott A.; Steward, V. W.

doi:10.1097/00004728-198208000-00062

Cited by 12 publications

(15 citation statements)

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“…Since the ratio Z/A is fairly constant for human tissues, the electron density closely reflects the physical density of the imaged tissues. To avoid the large numbers associated with absolute volume electron density values (which are of the order of 10 23 electrons/cm 3 ), it is better to express results in terms of relative volume electron density, which is defined as water e e e , ρ ρ η = ( 2 ) where ρ e,water = 3.343 × 10 23 electrons/cm 3 is the volume electron density of water.…”

Section: Principle Of Proton Ctmentioning

confidence: 99%

“…Its unique imaging characteristics based on linear stopping power of charged particles, as compared to the x-ray attenuation coefficient, may prove beneficial in medical diagnosis. Secondly, a successful implementation of pCT would avoid or simplify many of the current tedious procedures for proton therapy, including xCT imaging, mapping of xCT numbers to proton stopping power values, moving and repositioning the patient, and patient position-checking in the treatment room [1,2]. A conceptual pCT system, which is similar to the first generation of xCT, is illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Reconstruction with most likely trajectory for proton computed tomography

Liang

2004

SPIE Proceedings

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Advantages of proton computed tomography (pCT) have been recognized in the past decades. However, the quality of pCT images is limited due to the stochastic nature of the proton path inside the object. Numerous small angle scatters by the nuclei Coulomb field cause the exact proton path impossible to trace. The reconstruction from measurements of the proton energy-loss has a spatial resolution limit due to these deflections. However, it has been shown that the proton path inside a uniform medium follows certain probability distribution so that a most likely trajectory (MLT) can be derived analytically for each proton. For real scan of a regular non-uniform object in pCT, the internal trajectory is better approximated by the MLT rather than a straight-line estimation. In this report, we presented preliminary studies on how the curved trajectories would affect the quality of the reconstructed images, and how much improvement we can achieve in reconstruction with the exact trajectory information. Analytical simulations with three phantoms, including a uniform disk phantom, multi-hole Aluminum phantom and Shepp-Logan phantom, were performed using artificial internal trajectories calculated based on the entrance and exit proton information. Reconstructions with the exact paths were compared to those with the straight-line path estimation. Significant improvement in density uniformity and spatial resolution were observed in the reconstructions with the path information.

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Section: Principle Of Proton Ctmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reconstruction with most likely trajectory for proton computed tomography

Liang

2004

SPIE Proceedings

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“…Proton radiography and tomography as a diagnostic tool was investigated in the early 1970s [1][2][3][4][5] but was more or less abandoned due to the success of X-ray-computed tomography. With the expansion of proton radiation therapy facilities, renewed interest has been placed in the development of a clinical proton radiography or tomography system.…”

Section: Introductionmentioning

confidence: 99%

Spatial resolution of proton tomography: Methods, initial phase space and object thickness

Schneider

Pedroni

Hartmann

et al. 2012

Zeitschrift für Medizinische Physik

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“…The use of protons for radiography was first suggested by Wilson 1 in 1946, but it was not until the sixties that charged particles, as opposed to x-rays, were first used to produce high contrast radiographs [2][3][4][5] . Proton radiography and tomography as diagnostic tools were more or less abandoned due to the success of x-ray computed tomography.…”

Section: Introductionmentioning

confidence: 99%

Quantitative proton radiography of an animal patient

et al. 2003

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Images (with a spatial resolution of 1 mm x 1mm) were produced both, with range and range dilution information of the protons passing through a dog. The radiographies were taken prior to a proton radiotherapy treatment of a nasal tumor, while the dog patient was under anesthetics. The first image was created by calculating the mean range of the protons detected in each pixel. This image was compared to calculations of the treatment planning system based on a CT-scan of the dog. Errors in the calculated range could be detected. The second image was produced by calculating the width of the range spectrum in each pixel. This value is a measure of the dilution of the range due to tissue inhomogeneities. The dilution image can be used to indicate critical situations during proton therapy, to determine the safety margin around the tumor volume, or to optimise treatment. In a preliminary analysis of the radiography data we found range uncertainty and range dilution effects in the order of up to 10 mm.

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Proton Computed Tomography of Human Specimens

Cited by 12 publications

References 0 publications

Reconstruction with most likely trajectory for proton computed tomography

Reconstruction with most likely trajectory for proton computed tomography

Spatial resolution of proton tomography: Methods, initial phase space and object thickness

Quantitative proton radiography of an animal patient

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