scholarly journals Gamma Radiation Imaging System via Variable and Time-Multiplexed Pinhole Arrays

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3013 ◽  
Author(s):  
Ariel Schwarz ◽  
Amir Shemer ◽  
Yossef Danan ◽  
Rachel Bar-Shalom ◽  
Hemy Avraham ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Imaging System ◽  
Single Photon ◽  
Photon Emission ◽  
Three Dimensional ◽  
Medical Diagnostics ◽  
Emission Computed Tomography ◽  
Planar Imaging ◽  
Gamma Imaging ◽  
Image Capturing

Biomedical planar imaging using gamma radiation is a very important screening tool for medical diagnostics. Since lens imaging is not available in gamma imaging, the current methods use lead collimator or pinhole techniques to perform imaging. However, due to ineffective utilization of the gamma radiation emitted from the patient’s body and the radioactive dose limit in patients, poor image signal to noise ratio (SNR) and long image capturing time are evident. Furthermore, the resolution is related to the pinhole diameter, thus there is a tradeoff between SNR and resolution. Our objectives are to reduce the radioactive dose given to the patient and to preserve or improve SNR, resolution and capturing time while incorporating three-dimensional capabilities in existing gamma imaging systems. The proposed imaging system is based on super-resolved time-multiplexing methods using both variable and moving pinhole arrays. Simulations were performed both in MATLAB and GEANT4, and gamma single photon emission computed tomography (SPECT) experiments were conducted to support theory and simulations. The proposed method is able to reduce the radioactive dose and image capturing time and to improve SNR and resolution. The results and method enhance the gamma imaging capabilities that exist in current systems, while providing three-dimensional data on the object.

Relationship of gastric emptying and volume changes after a solid meal in humans

2005 ◽  
Vol 289 (2) ◽  
pp. G261-G266 ◽  
Author(s):  
Duane D. Burton ◽  
H. Jae Kim ◽  
Michael Camilleri ◽  
Debra A. Stephens ◽  
Brian P. Mullan ◽  
...  
Keyword(s):  
Gastric Emptying ◽  
Volume Change ◽  
Single Photon ◽  
Photon Emission ◽  
Gastric Volume ◽  
Spect Imaging ◽  
Emission Computed Tomography ◽  
Planar Imaging ◽  
Solid Meal ◽  
3 Dimensional

Noninvasive imaging has been developed to measure gastric volumes. The relationship between gastric emptying and volume postprandially is unclear. The aims were to 1) develop a 3-dimensional (3D) single photon emission-computed tomography (SPECT) method to simultaneously measure gastric volume and emptying postprandially, 2) describe the course of gastric volume change during emptying of the meal, and 3) assess a 3D method measuring gastric emptying. In 30 healthy volunteers, we used 111In-planar and 99mTc-SPECT imaging to estimate gastric emptying and volume after a radiolabeled meal. A customized analysis program of SPECT imaging assessed gastric emptying. A Bland-Altman plot assessed the performance of the new SPECT analysis compared with planar analysis. Gastric volume postprandially exceeds the fasting volume plus meal volume. The course of volume change and gastric emptying differ over time. Higher differences in volumes exist relative to fasting plus residual meal volumes at 15 min (median 763 vs. 568 ml, respectively, P < 0.001), 1 h (median 632 vs. 524 ml, P < 0.001), and 2 h (median 518 vs. 428 ml, P < 0.02), in contrast to similar volumes at 3 h (median 320 vs. 314 ml, P = 0.85). Analysis of SPECT imaging accurately measures gastric emptying compared with planar imaging with median differences of 1% (IQR −2.25 to 2.0) at 1 h, 1% (−3.25 to 2.25) at 2 h, and −2.5% (−4 to 0) at 3 h. Gastric volume exceeds meal volume during the first 2 postprandial hours, and simultaneous measurements of gastric volume and emptying can be achieved with a novel 3D SPECT method.

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