Clinical performance of a 14-in. x 14-in. real-time amorphous selenium flat-panel detector

Tousignant, O.; Demers, Y.; Laperrière, Luc; Nishiki, Masayuki; Nagai, Seiichirou; Tomisaki, Takayuki; Takahashi, Akihito; Aoki, Kunio

doi:10.1117/12.480250

Cited by 5 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have reported, since 2000, continuous progress in the development of real-time a-Se flat panel detectors 1,2,3,4 starting from prototype to production products. Based on a multilayer PIN type a-Se structure deposited on a 150 µm pixel pitch thin film transistor (TFT) array, active areas of FPD9 and FPD14 are respectively 23x23 cm 2 and 34.5x34.5 cm 2 corresponding to 1536x1536 and 2304x2304 pixels.…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector

Tousignant¹,

Demers²,

Laperrière³

et al. 2005

Medical Imaging 2005: Physics of Medical Imaging

Self Cite

View full text Add to dashboard Cite

Large area, real-time, amorphous selenium (a-Se) based Flat Panel Detectors (FPD) were recently equipped with low noise front end electronics. In full resolution, 14"x14" detectors (FPD14) and 9"x9" detectors (FPD9) show an electronic noise of 1400 electrons. To evaluate the positive impact of such low noise on image quality, a dedicated report on spatial characteristics (MTF, NPS and DQE) covering the low dose range from 0.6 µR to 12 µR per frame, will be presented in the first section of this paper. For one RQA5 beam quality, DQE corrected for lag extrapolated at zero spatial frequency was equal to 0.6 for quantum noise limited exposure and equal to 0.4 for 0.6 µR. Almost no difference was found between 1x1 and 2x2 resolution mode giving the opportunity to 1x1 fluoroscopy. Recent advances to reduce image temporal artifacts such as lag and ghost will make the second part of this paper. It is demonstrated that the most significant contribution to detector lag is coming from the PIN selenium structure. Above electric field of 10 V/µm charges release from traps following one x-ray exposure could not explain selenium lag. Active ghost correction based on deep trapped charge recombination was developed giving good preliminary results in showing no residual ghost for a high dose rate of 33 mR/min.

show abstract

Section: Introductionmentioning

confidence: 99%

Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector

Tousignant¹,

Demers²,

Laperrière³

et al. 2005

Medical Imaging 2005: Physics of Medical Imaging

Self Cite

View full text Add to dashboard Cite

show abstract

“…This was observed as a deviation from the ideal linear behavior of SNR versus detector entrance exposure at lower exposures such as those used in fluoroscopic procedures. Similar to Roos, several other authors have used an approach of plotting SNR versus exposure to determine an approximate threshold exposure (Suzuki et al 2002, Tousignant et al 2003). Various other methods have also been used in an attempt to determine the x-ray quantum-limited range of exposures including measuring the dark-field NPS to determine the electronic noise level and comparing this to the total noise at zero spatial frequency, with the anisotropic ASIC noise and the electronic noise subtracted as a function of exposure (Hunt et al 2004) and by examining the exposure at which the zero-frequency DQE drops to one-half its high dose value (Hunt et al 2003, Zhao et al 2003).…”

Section: Introductionmentioning

confidence: 99%

A practical exposure-equivalent metric for instrumentation noise in x-ray imaging systems

et al. 2008

View full text Add to dashboard Cite

The performance of high-sensitivity x-ray imagers may be limited by additive instrumentation noise rather than by quantum noise when operated at the low exposure rates used in fluoroscopic procedures. The equipment-invasive instrumentation noise measures (in terms of electrons) are generally difficult to make and are potentially not as helpful in clinical practice as would be a direct radiological representation of such noise that may be determined in the field. In this work, we define a clinically relevant representation for instrumentation noise in terms of noise-equivalent detector entrance exposure, termed the instrumentation noise-equivalent exposure (INEE), which can be determined through experimental measurements of noise-variance or signal-to-noise ratio (SNR). The INEE was measured for various detectors, thus demonstrating its usefulness in terms of providing information about the effective operating range of the various detectors. A simulation study is presented to demonstrate the robustness of this metric against post-processing, and its dependence on inherent detector blur. These studies suggest that the INEE may be a practical gauge to determine and compare the range of quantum-limited performance for clinical x-ray detectors of different design, with the implication that detector performance at exposures below the INEE will be instrumentation-noise limited rather than quantum-noise limited.

show abstract

“…The motion of these free charge carriers induces imaging signal in the pixels. The numerous advantages of AMFPIs (real-time readout, compact profile, superior image quality, etc) have led to their widespread acceptance in an increasing number of medical applications, including radiography, fluoroscopy, cardiac imaging, mammography and radiotherapy imaging (Antonuk 2002, Granfors et al 2001, Colbeth et al 2001, Ikeda et al 2003, Samei and Flynn 2003, Vedantham et al 2000, Tousignant et al 2003.…”

Section: Introductionmentioning

confidence: 99%

Systematic investigation of the signal properties of polycrystalline HgI₂detectors under mammographic, radiographic, fluoroscopic and radiotherapy irradiation conditions

Antonuk

El‐Mohri

et al. 2005

Phys. Med. Biol.

View full text Add to dashboard Cite

The signal properties of polycrystalline mercuric iodide (HgI2) film detectors, under irradiation conditions relevant to mammographic, radiographic, fluoroscopic and radiotherapy x-ray imaging, are reported. Each film detector consists of an approximately 230 to approximately 460 microm thick layer of HgI2 (fabricated through physical vapour deposition or a screen-print process) and a thin barrier layer, sandwiched between a pair of opposing electrode plates. The high atomic number, high density and low effective ionization energy, W(EFF), of HgI2 make it an attractive candidate for significantly improving the performance of active matrix, flat-panel imagers (AMFPIs) for several x-ray imaging applications. The temporal behaviour of current from the film detectors in the presence and in the absence of radiation was used to examine dark current levels, the lag and reciprocity of the signal response, x-ray sensitivity and W(EFF). The results are discussed in the context of present AMFPI performance. This study provides performance data for a wide range of potential medical x-ray imaging applications from a single set of detectors and represents the first investigation of the signal properties of polycrystalline mercuric iodide for the radiotherapy application.

show abstract

Clinical performance of a 14-in. x 14-in. real-time amorphous selenium flat-panel detector

Cited by 5 publications

References 0 publications

Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector

Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector

A practical exposure-equivalent metric for instrumentation noise in x-ray imaging systems

Systematic investigation of the signal properties of polycrystalline HgI₂detectors under mammographic, radiographic, fluoroscopic and radiotherapy irradiation conditions

Contact Info

Product

Resources

About

Clinical performance of a 14-in. x 14-in. real-time amorphous selenium flat-panel detector

Cited by 5 publications

References 0 publications

Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector

Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector

A practical exposure-equivalent metric for instrumentation noise in x-ray imaging systems

Systematic investigation of the signal properties of polycrystalline HgI2detectors under mammographic, radiographic, fluoroscopic and radiotherapy irradiation conditions

Contact Info

Product

Resources

About

Systematic investigation of the signal properties of polycrystalline HgI₂detectors under mammographic, radiographic, fluoroscopic and radiotherapy irradiation conditions