Usage of two types of high-pressure xenon chambers for medical radiography

Babichev, E.A.; Baru, S.E.; Groshev, V.R.; Khabakhpashev, A.G.; Krainov, G. S.; Leonov, V.V.; Neustroev, V.A.; Porosev, V.V.; Savinov, G.A.

doi:10.1016/s0168-9002(00)01267-5

Cited by 10 publications

(4 citation statements)

References 3 publications

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“…As a result, some studies have suggested that the SSDR method could be an alternative to other digital techniques ( 2 ). Some studies have also cited the advantages of using a MIC detector ( 15 , 16 ). Since the MIC detector is a direct conversion type, it enables a high counting rate, high spatial resolution, low sensitivity to gas impurity, and low cost ( 16 ).…”

Section: Discussionmentioning

confidence: 99%

Slot-Scan Digital Radiography of the Lower Extremities: a Comparison to Computed Radiography with Respect to Image Quality and Radiation Dose

et al. 2009

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ObjectiveTo compare the slot-scan digital radiography (SSDR) of the lower extremity region and the computed radiography (CR) method with respect to the image quality and radiation exposure.Materials and MethodsWe enrolled 54 patients who underwent both the SSDR and CR of the lower extremities. The study evaluated and statistically compared the image quality of four features (outer cortex, inner cortex, trabeculae and intermuscular fat) at six different levels (pelvis, hip, femur, knee, tibia and ankle) between each method. The image quality was evaluated using a visibility scale, and the entrance skin dose was measured using a dosimeter at three different levels of a phantom (hip, knee, and ankle).ResultsThe mean image visibility scale values for the SSDR method were significantly higher than for the CR method. The entrance skin dose for the SSDR method was 278 µGy at each level, compared to the entrance skin doses of the CR method, which were 3,410 µGy for the hip, 1,152 µGy for the knee, and 580 µGy for the ankle.ConclusionBoth the image quality and patient entrance skin dose data suggest that the SSDR method is superior to the CR method for the lower extremity musculoskeletal examination.

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Section: Discussionmentioning

confidence: 99%

Slot-Scan Digital Radiography of the Lower Extremities: a Comparison to Computed Radiography with Respect to Image Quality and Radiation Dose

et al. 2009

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“…A one-dimension MWPC filled with X e + 20%CO 2 at 3 atm was used in the first series of experiments (at a 15-degree angle). This detector was originally designed for the low-dose digital radiographic device (LDRD) "Siberia" [5]. The anode plane of the detector consists of 320 wires, 12 µm in diameter, with a pitch of 1.2 mm.…”

Section: The Design and Characteristics Of The Installationmentioning

confidence: 99%

Application of gas-filled detectors for well logging

2008

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The advantages of using gas-filled multiwire proportional chambers (MWPC) for well logging are discussed. In particular, applicability of the MWPC in casing quality control and cement bond logging is described. It is shown that spatial distribution measurement of scattered gamma rays can provide information about the material and presence of the defects. The results of computations performed with GEANT4 are in the reasonable agreement with the experimental data. KEYWORDS: X-ray detectors; Gaseous detectors; Detection of defects; Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc).

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“…12 Rare gas ionization chambers have been extensively used as radiation detectors in radiographic and spectroscopic applications. [17][18][19] However, this article addresses the particular case of the KCD whose unique mode of operation entails a detailed analysis of ion recombination including its specific effect on KCD image quality.…”

Section: A Kinestatic Charge Detectionmentioning

confidence: 99%

Effect of recombination in a high quantum efficiency prototype ionization‐chamber‐based electronic portal imaging device

Gopal

Samant

2007

Medical Physics

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The quantum efficiency (QE) of an imaging detector can be increased by utilizing a thick, high-density detection medium to increase the number of quantum interactions. However, image quality is more accurately described by the detection quantum efficiency (DQE). If a significant fraction of the increase in the number of detected quanta from a thick, dense detector were to result in useful imaging signal, this represents a favorable case where enhanced QE leads to increased DQE. However, for ionization-type detectors, one factor that limits DQE is the recombination between ion pairs that acts as a secondary quantum sink due to which enhancement in QE may not result in higher DQE depending on the extent of the signal loss from recombination. Therefore, an analysis of signal loss mechanisms or quantum sinks in an imaging system is essential for validating the overall benefit of high QE detectors. In this paper, a study of ion recombination as a secondary quantum sink is presented for a high QE prototype ion-chamber-based electronic portal imaging device (EPID): the kinestatic charge detector (KCD). The KCD utilizes a high pressure noble gas (krypton or xenon at 100 atm) and an arbitrarily large detector thickness (of the order of centimeters), resulting in a high QE imager. Compared with commercial amorphous silicon flat panel imagers that provide DQE(0) approximately 0.01, the KCD has much higher DQE. Studies indicated that DQE(0) = 0.20 for 6.1 cm thick, 100 atm (rho = 3.4 g/cm3) xenon chamber, and DQE(0)=0.34 for a 9.1 cm thick chamber. A series of experiments was devised and conducted to determine the signal loss due to recombination for a KCD chamber. The measurements indicated a fractional recombination loss of about 14% for a krypton chamber and about 18% for a xenon chamber under standard operating conditions (100 atm chamber pressure and 1275 V/cm electric field intensity). A theoretical treatment of the effect of recombination on imaging signal-to-noise ratio was applied to quantify the loss in DQE. These calculations indicated that recombination had a limited effect (<2%) on DQE under standard operating conditions. This was validated by good agreement between experimentally measured DQE and that obtained using Monte Carlo simulations that did not account for recombination.

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Usage of two types of high-pressure xenon chambers for medical radiography

Cited by 10 publications

References 3 publications

Slot-Scan Digital Radiography of the Lower Extremities: a Comparison to Computed Radiography with Respect to Image Quality and Radiation Dose

Slot-Scan Digital Radiography of the Lower Extremities: a Comparison to Computed Radiography with Respect to Image Quality and Radiation Dose

Application of gas-filled detectors for well logging

Effect of recombination in a high quantum efficiency prototype ionization‐chamber‐based electronic portal imaging device

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