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For professional tennis players, the choice between becoming a singles player or a doubles player is an important issue. In my research so far, players can be classified into "precocious" and "late-blooming" types based on whether the men's singles world ranking is ranked 100th at the age of 20. The purpose of this study is to help young players build their careers by clarifying their limits as a singles player and their potential as a doubles player at the age of 20. Doubles players receive the same or higher prize money than singles players if they have the same ranking at the age of 20. In addition, it is difficult for singles players to rank 100th in the singles ranking if they have not reached the 300th rank at the age of 20. However, even if the doubles players are ranked 701 to 900 at the age of 20, more than half of the players can be ranked 100th in the doubles ranking. The prize money earned by compatible players who participated in both singles and doubles games (about 50% each) was lower than that of doubles players.

The purpose of this study is to improve muscle mass (skeletal muscle mass) in college elite tennis players by training and supplemental protein intake in order to maintain and improve their performance throughout the year. In tennis, tournaments are held every week and endurance is required to win. Since the matches are mainly tournament-style, the more competitive a player is, the more matches he or she must play. For elite tennis players, improving and maintaining their physical fitness is an important factor in improving their competitiveness as they play about 60 matches a year. Muscle mass gain can improve sports performance, and at the same time, protein intake is important. There is still a lack of data on annual changes in muscle mass in tennis competitions. In this study, we recorded and analyzed the changes in muscle mass of elite college tennis players by taking a supplementary diet for protein intake at the same time as resistance training. The results were shown that skeletal muscle mass increased when supplemented and trained. In particular, athletes with lower skeletal muscle mass before this experiment tended to increase skeletal muscle mass by training and supplemental protein intake.

The quality and uniformity of positron emission tomography (PET) images can be improved significantly using a PET scanner, which has both time-of-flight (TOF) and depth-of-interaction (DOI) capabilities. We have already developed a DOI dual-end detector using segmented crystal bars by applying a subsurface laser engraving (SSLE) technique, and the DOI was determined by the ratio of the detected light between two readouts using the Anger calculation. In this study, we investigated the influence of the number of DOI segments on the performance of DOI identification and the coincidence timing performance of the detector. The detector consisted of a single lutetium fine silicate (LFS) crystal bar (3×3×20 mm3) with various numbers of DOI segments that were made by applying the SSLE technique and Hamamatsu silicon photomultiplier (SiPM) modules. The maximum number of DOI segments was six, and the SiPM module included one hundred forty four 4 mm × 4 mm SiPM readouts. The coincidence resolving time (CRT) of each DOI segment was obtained from the side irradiation of the dual-end detector. All DOI segments of the detector with 2, 3, 4, 5 or 6 DOI segments were clearly identified, and average energy resolutions of 9.8 ± 0.5% and 12.5 ± 1.4% were obtained at the 511 keV photo peak for the detectors with 2 DOI and 6 DOI segments, respectively. The minimum and maximum estimated CRT of 180 ± 6 ps and 236 ± 6 ps were obtained for the detectors with 2 DOI and 6 DOI segments, respectively. Insignificant differences were observed between the CRT values of different segments of one detector. Greater CRT values were obtained for detectors with larger DOIs. The results of this study prove that there is a high potential for segmented crystal bars using the SSLE technique as a good candidate for PET scanners with TOF and DOI capabilities, which can significantly improve the quality of PET images.

A small animal depth-of-interaction (DOI) positron emission tomography (PET) detector based on a trapezoid shaped crystal was originally proposed by Simon Cherry’s group at UC Davis as a way to minimize the gaps between detector blocks. However, manufacturing the trapezoid shaped crystal is costly due to the complex geometry. As a more practical idea, here we developed a small animal DOI PET detector using a sub-surface laser engraving (SSLE) based trapezoid geometry. The imaging performance of the proposed PET scanner was presented in the most recent GATE User’s workshop. In the developed detector, we pixelized a 20 mm long monolithic trapezoid LYSO plate (top = 15.3 mm, bottom = 25.6 mm, thickness = 0.9 mm) into a 15 × 1 array by using SSLE to yield a top crystal pitch of 1.02 mm and a bottom crystal pitch of 1.71 mm. The 11 SSLE processed LYSO crystal plates were assembled together to make a 15 × 11 array. The LYSO plates were optically isolated by using as enhanced specular reflector (ESR). A 7×6 array SiPM (S13360-2050VE, Hamamatsu Photonics, Japan) with a pixel pitch of 2.4 mm and an 8×4 array SiPM (S13361-3050NE-04 Hamamatsu Photonics) with a pixel pitch of 3.2 mm were coupled to the top and bottom surfaces of the trapezoid LYSO array, respectively. For an optical coupling, room temperature vulcanized (RTV) light guides with a thickness of 1 mm were inserted between the LYSO and SiPM array. The SiPM output signals were multiplexed by using a resistive network, and then digitized by CAMAC DAQ. We could identify all the crystals in the 2D flood map. The measured DOI resolution and energy resolution were 2.3±0.6 mm and 11.6±0.7%, respectively. In the future, we want to develop a prototype trapezoid geometry small animal DOI PET scanner for high-resolution and high-sensitivity mouse brain imaging., 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference

In the previous work, we developed a high resolution depth of interaction (DOI) positron emission tomography (PET) detector called X’tal cube by using 3D subsurface laser engraving (SSLE) technique [1]. However, the X’tal cube requires a long 3D laser processing time and six SiPMs for readout. Moreover, the gaps between the detector blocks result in a sensitivity loss. In this study, we propose a novel SSLE based trapezoid geometry DOI PET detector which can solve these issues by using stacking of 2D SSLE processed LYSO plates and dual-ended readout approaches. A 20 mm long monolithic trapezoid LYSO plate (Top: 15.3 mm, bottom: 25.6 mm, thickness = 0.9 mm) was segmented in 15 × 10 (DOI) array by using SSLE to yield a top crystal pitch of 1.02 mm, a bottom crystal pitch of 1.71 mm, and 2.0 mm DOI bin, respectively (Fig. 1). Three laser processed LYSO crystal plates were stacked and optically isolated by using ESR film. A 7×6 array SiPM (pitch=2.4 mm) and 8×4 array SiPM (pitch=3.2 mm) were coupled to the top and bottom of the trapezoid LYSO array, respectively (Fig. 1). The DOI information was extracted by using the signal amplitude ratio of the two SiPMs (top and bottom). All the LYSO segments could be identified in the flood map (Fig. 2(a)). The DOI resolution and energy resolution were measured to be 2.0 mm and 11.4%, respectively (Fig. 2(b) and 2(c)). In future, a prototype submillimeter resolution small animal PET scanner will be developed by using the SSLE based trapezoid shape dual-ended readout PET detector., 15th Int. SCINT 2019

[Purpose] Small animal positron emission tomography (PET) has been playing an important role in preclinical research. However, a conventional PET scanner has a large gap between the detector blocks due to the box shape crystal geometry which resulted in a sensitivity loss. The aim of this study is to develop a trapezoid crystal based small animal PET detector using subsurface laser engraving (SSLE) technique for high sensitivity and high resolution PET scanner research. [Methods] The proposed trapezoidal geometry small animal DOI PET detector consists of a three trapezoid LYSO plates, and multi-pixel photon counters (MPPCs). The 0.9 mm thick LYSO plates were pixelized by SSLE in X-direction with pixel pitches of 1.02 mm and 1.707 mm at the top and bottom surfaces, respectively. The LYSO in DOI direction was remained as continuous without SSLE processing. The SSLE processed LYSO plates were optically isolated each other by ESR reflector direction. The scintillation light from the top and bottom surfaces of trapezoid LYSO crystal was readout by a 7×6 array MPPC (Pitch=2.4 mm), and an 8×4 array MPPC (Pitch=3.2 mm), respectively. In order to evaluate the DOI resolution, a collimated 511 keV photon was irradiated to the LYSO crystal (lead slit width=1.2 mm) for different DOI positions (2, 6, 10, 14, and, 18 mm). The DOI resolution was calculated by using the signal amplitude ratio of the two MPPCs. [Results] All the 15×3 LYSO crystals could be resolved clearly. The energy resolution and DOI resolution were measured to be less than 25% and 3.5 mm, respectively. The DOI ratio showed non-linear characteristics due to the trapezoid crystal geometry. [Conclusion] In conclusion, we demonstrated the feasibility of a trapezoid geometry small animal DOI PET detector using SSLE technique. In the future, a prototype trapezoid geometry small animal PET scanner will be developed., 第117回日本医学物理学会学術大会