Theoretical and empirical investigations of  for nearly water‐equivalent radiotherapy dosimetry

Zheng, Yuanshui; Han, Zhaohui; Driewer, J; Low, Daniel A.; Li, H. Harold

doi:10.1118/1.3271338

Cited by 17 publications

(25 citation statements)

References 26 publications

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“…Storage phosphors, or computed radiography (CR) plates, could also potentially provide a 2D dose distribution, but they have been generally used in high energy radiation therapy situations, unlike the diagnostic energy range detailed in this study. 19,20 In addition, although storage phosphor plates come in a variety of sizes, they cannot be submerged in any type of liquid since the liquid would render the plate unreadable in the CR plate readout device.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the absorbed dose to the breast using radiochromic film in a dedicated CT mammotomography system employing a quasi-monochromatic x-ray beam

et al. 2011

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Purpose: A dual modality SPECT-CT prototype system dedicated to uncompressed breast imaging (mammotomography) has been developed. The computed tomography subsystem incorporates an ultrathick K-edge filtration technique producing a quasi-monochromatic x-ray cone beam that optimizes the dose efficiency of the system for lesion imaging in an uncompressed breast. Here, the absorbed dose in various geometric phantoms and in an uncompressed and pendant cadaveric breast using a normal tomographic cone beam imaging protocol is characterized using both thermoluminescent dosimeter (TLD) measurements and ionization chamber-calibrated radiochromic film. Methods: Initially, two geometric phantoms and an anthropomorphic breast phantom are filled in turn with oil and water to simulate the dose to objects that mimic various breast shapes having effective density bounds of 100% fatty and glandular breast compositions, respectively. Ultimately, an excised human cadaver breast is tomographically scanned using the normal tomographic imaging protocol, and the dose to the breast tissue is evaluated and compared to the earlier phantom-based measurements. Results: Measured trends in dose distribution across all breast geometric and anthropomorphic phantom volumes indicate lower doses in the medial breast and more proximal to the chest wall, with consequently higher doses near the lateral peripheries and nipple regions. Measured doses to the oil-filled phantoms are consistently lower across all volume shapes due to the reduced mass energy-absorption coefficient of oil relative to water. The mean measured dose to the breast cadaver, composed of adipose and glandular tissues, was measured to be 4.2 mGy compared to a mean whole-breast dose of 3.8 and 4.5 mGy for the oil-and water-filled anthropomorphic breast phantoms, respectively. Conclusions: Assuming rotational symmetry due to the tomographic acquisition exposures, these results characterize the 3D dose distributions in an uncompressed human breast tissue volume for this dedicated breast imaging device and illustrate advantages of using the novel ultrathick K-edge filtered beam to minimize the dose to the breast during fully-3D imaging.

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Section: Introductionmentioning

confidence: 99%

Evaluation of the absorbed dose to the breast using radiochromic film in a dedicated CT mammotomography system employing a quasi-monochromatic x-ray beam

et al. 2011

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“…As a result, increased energy dependence occurs. Zheng et al (Zheng et al, 2010) confirmed this suggestion through Monte Carlo simulations. This reasoning also explains why AgBr radiographic film, with a sensitive layer on the order of a few microns thick, did not show a strong energy-dependence as would be expected due to its high effective Z of 43 (Low et al , 2011).…”

Section: Discussionmentioning

confidence: 71%

Two-dimensional high spatial-resolution dosimeter using europium doped potassium chloride: a feasibility study

Driewer

Han

et al. 2014

Phys. Med. Biol.

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Recent research has shown that KCl:Eu2+ has great potential for use in megavoltage radiation therapy dosimetry because this material exhibits excellent storage performance and is reusable due to strong radiation hardness. This work reports the authors’ attempts to fabricate 2D KCl:Eu2+ storage phosphor films (SPFs) using both a physical vapor deposition (PVD) method and a tape casting method. X ray diffraction analysis showed that a 10 µm thick PVD sample was composed of highly crystalline KCl. No additional phases were observed, suggesting that the europium activator had completed been incorporated into the KCl matrix. Photostimulated luminescence and photoluminescence spectra suggested that F (Cl-) centers were the electron storage centers post×ray irradiation and that Eu2+ cations acted as luminescence centers in the photostimulation process. The 150-µm thick casted KCl:Eu2+ SPF showed sub-millimeter spatial resolution. Monte Carlo simulations further demonstrated that the admixture of 20% KCl:Eu2+ and 80% low Z polymer binder exhibited almost no energy dependence in a 6 MV beam. KCl:Eu2+ pellet samples showed a large dynamic range from 0.01 cGy to 60 Gy dose-to-water, and saturated at approximately 500 Gy as a result of KCl’s intrinsic high radiation hardness. Taken together, this work provides strong evidence that KCl:Eu2+ based SPF with associated readout apparatus could result in a novel electronic film system that has all the desirable features associated with classic radiographic film and, importantly, water equivalence and the capability of permanent identification of each detector.

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“…Recently, we have shown that KCl:Eu 2+ -based dosimeters provide similar energy response as radiographic film [2, 3]. The Z eff is 18, which is much closer to tissue than BaFBrI or CsBr.…”

Section: Introductionmentioning

confidence: 99%

X-ray storage performance of KCl:Eu2+ with high cumulated dose

Hansel

Xiao

Zhang

et al. 2014

Nuclear Instruments and Methods in Physics Research Section B:

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The effects of high cumulative radiation dose on the luminescence properties of KCl:Eu2+ are investigated. Pellet samples of KCl:Eu2+ were given doses of up to 200 kGy at the Louisiana State University Synchrotron facility. After synchrotron irradiation, samples were optically bleached and given a clinical dose of 2 Gy from a 6 MV medical linear accelerator. Optical properties were evaluated using photostimulated luminescence (PSL), photoluminescence (PL), and temperature-dependent PSL measurements. For a cumulated dose of up to 5–10 kGy, the PSL emission intensity increased by 15% compared to the PSL signal with no radiation history. For doses higher than 10 kGy, the PSL emission intensity retained at least 70% of the original intensity. Spatial correlation of the charge storage centers increased for doses up to 5 kGy and then decreased for higher cumulative doses. Emission band at 975 nm was attributed to transitions of Eu1+. PL spectra showed an intense peak centered at 420 nm for all cumulative doses. The results of this work show that KCl:Eu2+ storage phosphors are excellent reusable materials for radiation therapy dosimetry.

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Theoretical and empirical investigations of for nearly water‐equivalent radiotherapy dosimetry

Cited by 17 publications

References 26 publications

Evaluation of the absorbed dose to the breast using radiochromic film in a dedicated CT mammotomography system employing a quasi-monochromatic x-ray beam

Evaluation of the absorbed dose to the breast using radiochromic film in a dedicated CT mammotomography system employing a quasi-monochromatic x-ray beam

Two-dimensional high spatial-resolution dosimeter using europium doped potassium chloride: a feasibility study

X-ray storage performance of KCl:Eu2+ with high cumulated dose

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