The timing resolution of this PET scanner enables a precise TOF measurement for the coincident photons from each annihilation event. The fast timing properties, high light output, and high stopping power of LYSO combined with this detector design lead to a high-sensitivity scanner with good counting rate capability and very good spatial, energy, and timing resolutions. The PET scanner uses small, discrete lutetium-yttrium oxyorthosilicate (, with the Lu-to-Yt ratio of 9:1) crystals placed in an Anger-logic detector design to achieve uniform light spread in the detector. It was installed at the University of Pennsylvania PET Center in November 2005 and, after a period of evaluation and performance of research studies, is now being routinely used for clinical studies since May 2006. The Gemini TF PET/CT (Philips Medical Systems) is a new high-performance, time-of-flight (TOF) capable, fully 3-dimensional (3D) PET scanner together with a 16-slice Brilliance CT scanner. The most significant improvement with TOF is seen for the heaviest patients. Excellent image quality is achieved for whole-body studies in 10–30 min, depending on patient size. The timing resolution is also stable over a long duration, indicating the practicality of this device. Conclusion: The Gemini TF whole-body scanner represents the first commercially available fully 3-dimensional PET scanner that achieves TOF capability as well as conventional imaging capabilities. However, the benefit of TOF is more apparent with the large 35-cm-diameter phantom, where small spheres are detectable only with TOF information for short scan times. Image-quality measurements with the torso phantom show that very high quality images can be obtained with short scan times (1–2 min per bed position). The timing resolution changes as a function of the singles rate due to pulse pileup and could impact TOF image reconstruction. The system coincidence timing resolution was measured to be 585 ps. The 2 larger cylinders showed a decrease in the peak NEC due to increased attenuation, scatter, and random coincidences, and the peak occurs at lower activity concentrations. For the same line source cylinder, the peak NEC rate is measured to be 125 kcps at an activity concentration of 17.4 kBq/mL (0.47 μCi/mL). The absolute sensitivity of this scanner measured with a 70-cm-long line source is 6.6 cps/kBq, whereas scatter fraction is 27% measured with a 70-cm-long line source in a 20-cm-diameter cylinder. Results: The transverse and axial resolution near the center is 4.8 mm. Finally, to characterize the effect of TOF reconstruction on lesion contrast and noise, the standard NEMA/International Electrotechnical Commission torso phantom as well as a large 35-cm-diameter phantom with both hot and cold spheres were imaged for varying scan times. Additional measurements to study the impact of pulse pileup at high counting rates on timing, as well as energy and spatial, resolution were also performed. New measurements were designed to characterize its intrinsic timing resolution capability, which defines its TOF performance. The scatter fraction and noise equivalent count (NEC) measurements with the NEMA cylinder (20-cm diameter) were repeated for 2 larger cylinders (27-cm and 35-cm diameter), which better represent average and heavy patients. Methods: Performance measurements on the scanner were made using the National Electrical Manufacturers Association (NEMA) NU2-2001 procedures to benchmark its conventional imaging capabilities. This scanner was designed to perform as a high-performance conventional PET scanner as well as provide good timing resolution to operate as a time-of-flight (TOF) PET scanner. It uses 4 × 4 × 22 mm 3 LYSO crystals arranged in a pixelated Anger-logic detector design. This scanner, which operates in a fully 3-dimensional mode, has a diameter of 90 cm and an axial field of view of 18 cm. import java.io.Results from a new PET/CT scanner using lutetium-yttrium oxyorthosilicate (LYSO) crystals for the PET component are presented. ![]() txt file in my "src" "bin" and main project folder but it still cannot find the file. I am getting the following error messages: java.io.FileNotFoundException: 10_Random (The system cannot find the file specified)Īt java.io.FileInputStream.open(Native Method)Īt java.io.FileInputStream.(Unknown Source)Īt insertionSort.main(insertionSort.java:14) I need help with getting the program to read the text file. I am working on a Java program that reads a text file line-by-line, each with a number, takes each number throws it into an array, then tries and use insertion sort to sort the array.
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