Mineral Characterization in Human Body: A Dual Energy Approach

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Background: Mammographic digital imaging is based on X-ray sensors with solid image quality characteristics. These primarily include (a) a response curve that yields high contrast and image latitude, (b) a frequency response given by the Modulation Transfer Function (MTF), which enables small detail imaging and (c) the Normalize Noise Power Spectrum (NNPS) that shows the extent of the noise effect on image clarity. Methods: In this work, a methodological approach is introduced and described for creating digital phantom images based on the measured image quality properties of the sensor. For this purpose, a mathematical phantom, simulating breast tissue and lesions of blood, adipose, muscle, Ca and Ca(50%)-P(50%) was created by considering the corresponding X-ray attenuation coefficients. The simulated irradiation conditions of the phantom used four mammographic spectra assuming exponential attenuation. Published data regarding noise and blur of a commercial RadEye HR CMOS imaging sensor were used as input data for the resulting images. Results: It was found that the Ca and Ca(50%)-P(50%) lesions were visible in all exposure conditions. In addition, the W/Rh spectrum at 28 kVp provided more detailed images than the corresponding Mo/Mo spectrum. Conclusions: The presented methodology can act complementarily to image quality measurements, leading to initial optimization of the X-ray exposure parameters per clinical condition.

Section: Discussionmentioning

confidence: 99%

A Novel Method to Model Image Creation Based on Mammographic Sensors Performance Parameters: A Theoretical Study

Kalyvas

Chamogeorgaki

Michail

et al. 2023

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“…Setting: teeth, optocoupler, LED. The dimensions of the X-ray images are 1200 × 1600 pixels, corresponding to an active area of 27 × 36 mm 2 [ 12 ].…”

Section: Figurementioning

confidence: 99%

“…The density and its effective atomic number greatly influence the radiation absorption efficiency. This in turn affects the signal to noise ratio Sensors 2023, 23, 6588 2 of 18 (SNR) { XE "signal to noise ratio:SNR" } and consequently the radiation dose that has to be delivered to the patient [9][10][11][12]. Other desired characteristics include the following: ruggedness and absence of hygroscopicity; low levels of afterglow; adequate homogeneity in the distribution of the emission centers (activator sites-impurities) within the phosphor mass, low manufacturing cost and complexity in the production process [6,13,14].…”

Section: Introductionmentioning

confidence: 99%

A Novel Method for Developing Thin Resin Scintillator Screens and Application in an X-ray CMOS Imaging Sensor

Linardatos

Fountos

Valais

et al. 2023

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Scintillating screens for X-ray imaging applications are prepared with various methods. Among them, the classic sedimentation method presents certain weak points. In this context, a novel fabrication process was developed that offers simplicity, economy of resources and time, while the screens exhibit adequate durability and image quality performance. The proposed technique involves a resin mixture that contains the phosphor in powder form (Gd2O2S:Tb in the present work) and graphite. The novel method was optimized and validated by coupling the screens to a complementary metal oxide semiconductor (CMOS) X-ray sensor. Indicatively, screens of two surface densities were examined; 34 mg/cm2 and 70 mg/cm2. Various established image quality metrics were calculated following the IEC 62220-1 international standard, including the detective quantum efficiency (DQE). Comparisons were carried out under the same conditions, with a sedimentation screen reported previously and a screen of wide commercial circulation (Carestream Min-R 2190). The novel screens exhibit has comparable or even better performance in image-quality metrics. The 34 mg/cm2 screen achieves a DQE 15–20% greater than its comparison counterpart, and its limiting resolution was 5.3 cycles/mm. The detector coupled to the 70 mg/cm2 screen achieved a DQE 10–24% greater than its own counterpart, and its limiting resolution was found to be 5.4 cycles/mm.

“…For example, (i) Gd 2 O 2 S:Tb powder phosphors are employed in X-ray projection [4] imaging (radiation imaging) and portal imaging systems (radiotherapy), and (ii) Gd 2 O 2 S:Pr ceramic phosphors are applied in X-ray computed tomography systems [5]. Figure 1 shows examples of non-destructive testing (NDT) CMOS imaging sensors, adopted for dual energy medical imaging applications and coupled with Gd 2 O 2 S:Tb phosphor screens [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Grain Size Distribution Analysis of Different Activator Doped Gd2O2S Powder Phosphors for Use in Medical Image Sensors

Liaparinos

Michail

Valais

et al. 2022

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The structural properties of phosphor materials, such as their grain size distribution (GSD), affect their overall optical emission performance. In the widely used gadolinium oxysulfide (Gd2O2S) host material, the type of activator is one significant parameter that also changes the GSD of the powder phosphor. For this reason, in this study, different phosphors samples of Gd2O2S:Tb, Gd2O2S:Eu, and Gd2O2S:Pr,Ce,F, were analyzed, their GSDs were experimentally determined using the scanning electron microscopy (SEM) technique, and thereafter, their optical emission profiles were investigated using the LIGHTAWE Monte Carlo simulation package. Two sets of GSDs were examined corresponding to approximately equal mean particle size, such as: (i) 1.232 μm, 1.769 μm and 1.784 μm, and (ii) 2.377 μm, 3.644 μm and 3.677 μm, for Tb, Eu and Pr,Ce,F, respectively. The results showed that light absorption was almost similar, for instance, 25.45% and 8.17% for both cases of Eu dopant utilizing a thin layer (100 μm), however, given a thicker layer (200 μm), the difference was more obvious, 22.82%. On the other hand, a high amount of light loss within the phosphor affects the laterally directed light quanta, which lead to sharper distributions and therefore to higher resolution properties of the samples.