PET/CT 검사에서 Q.Clear 기법의 유용성에 대한 고찰

최용훈,김정열,최영숙,임한상,김재삼,Choi, Yong Hoon,Kim, Jung Yul,Choi, Young Sook,Lim, Han Sang,Kim, Jae Sam 대한핵의학기술학회 2017 핵의학 기술 Vol.21 No.2

최근 PET/CT 장비의 성능의 발전과 다양한 기법의 개발로 민감도와 해상도등 영상 품질을 개선할 수 있게 되었다. 본 논문에서는 GE사의 Discovery IQ 장비의 Q.Clear (a fully convergent iterative reconstruction) 기법을 이용하여 영상의 질 향상에 유용성이 있는지 알아보고자 한다. 장비는 Discovery IQ (GE Healthcare, MI, USA)를 사용하였다. NEMA IEC Body Phantom의 배후방사능과 열소 체적(10 mm, 13 mm, 17 mm, 22 mm)의 비를 1:4로 하고 3분간 촬영하여 VPHDs (VUE Point High-Definition SharpIR)와 Q.Clear의 대조도를 비교 분석하였다. PET/SPECT Performance Phantom에 $^{18}F-FDG$를 187 MBq을 주입 후 4분간 촬영하여 해상도와 균일도를 비교 분석하였다. 그리고 100명의 임상 환자에서 질환의 종류와 상관없이 2 cm 미만의 작은 병소의 SUVmax를 측정하여 t-test 통계분석하였다. NEMA IEC Body Phantom에서 VPHDs와 Q.Clear의 대조도가 $63.6{\pm}5.7%$, $75{\pm}4.8%$로 나왔고 PET/SPECT Performance Phantom에서 해상도는 VPHDs가 9.2 mm, Q.Clear가 7.3 mm로 나왔다. 균일도는 Q.Clear가 10.8% 더 우수하였다. 임상 환자의 t-test 통계 결과 p-value가 0.021로 유의한 차이가 있었다. 임상환자에서 SUVmax는 Q.Clear에서 높게 측정 되었으며, 신호대 잡음 비도 우수하였다. 이는 부분체적효과의 영향을 줄였기 때문으로 볼 수 있다. Phantom test와 임상 환자의 결과 모두 Q.Clear를 적용 하였을 때 영상품질이 향상된 것을 확인하였다. 이러한 영상 품질 향상은 병소를 더욱 정확하게 발견할 수 있고 나아가 선량저감과 환자평가 그리고 영상 분석 등 다양한 방면에서 활용할 수 있을 것으로 사료된다. Purpose Recently, the performance of PET/CT scanner has been improved and various techniques have been developed to increase the image quality such as Sensitivity and Resolution. The purpose of this study is to evaluate the usefulness of Q.Clear (a fully convergent iterative reconstruction) technique of GE Discovery IQ equipment to enhance the image quality. Materials and Methods All scans were acquired by Discovery IQ (GE Healthcare, MI, USA). In NEMA IEC Body Phantom test, Background to Hot-sphere (10 mm, 13 mm, 17 mm, 22 mm) ratio was 1:4 and scan time was 3 minutes. The images were reconstructed by VPHDs (VUE Point High-Definition + SharpIR) and Q.Clear to evaluate each Contrast. We injected 18F-FDG 187 M㏃ to PET/SPECT Performance Phantom. And then it was scanned for 4 minutes to evaluate Resolution and Uniformity. T-test statistical analysis was performed on SUVmax of small lesions less than 2 cm in 100 clinical patients regardless of disease type. Results In the NEMA IEC Body Phantom, the Contrast was $63.6{\pm}5.7%$ (VPHDs) and $75{\pm}4.8%$ (Q.Clear). In the PET/SPECT Performance Phantom, the Resolution was 9.2 mm (VPHDs) and 7.3 mm (Q.Clear). Uniformity of Q.Clear was 10.8% better than VPHDs. T-test statistic of the clinical patients showed a significant difference of p value of 0.021. Conclusion Both the phantom test and the clinical results showed that the quality of the image was improved in Q.Clear was applied. The SUVmax was highly measured in Q.Clear and the lesions were clearly distinguished visually. Therefore Q.Clear can be useful in various aspects such as dose-reduction, patients evaluation and image analysis.

How Do the More Recent Reconstruction Algorithms Affect the Interpretation Criteria of PET/CT Images?

Antonella Matti,Giacomo Maria Lima,Cinzia Pettinato,Francesca Pietrobon,Felice Martinelli,Stefano Fanti 대한핵의학회 2019 핵의학 분자영상 Vol.53 No.3

Purpose Recently, a new Bayesian Penalized Likelihood (BPL) Reconstruction Algorithm was introduced by GE Healthcare, Q.Clear; it promises to provide better PET image resolution compared to the widely used Ordered Subset Expectation Maximization (OSEM). The aimof this study is to compare the performance of these two algorithms on several types of findings, in terms of image quality, lesion detectability, sensitivity, and specificity. Methods Between September 6th 2017 and July 31st 2018, 663 whole body 18F-FDG PET/CT scans were performed at the Nuclear Medicine Department of S. Martino Hospital (Belluno, Italy). Based on the availability of clinical/radiological follow-up data, 240 scans were retrospectively reviewed. For each scan, a hypermetabolic finding was selected, reporting both for OSEM and Q.Clear: SUVmax and SUVmean values of the finding, the liver and the background close to the finding; size of the finding; percentage variations of SUVmax and SUVmean. Each finding was subsequently correlated with clinical and radiological follow-up, to define its benign/malignant nature. Results Overall, Q.Clear improved the SUVvalues in each scan, especially in small findings (< 10mm), high SUVmax values (≥ 10), and medium/low backgrounds. Furthermore, Q.Clear amplifies the signal of hypermetabolic findings without modifying the background signal, which leads to an increase in signal-to-noise ratio, improving overall image quality. Finally, Q.Clear did not affect PET sensitivity or specificity, in terms of number of reported findings and characterization of their nature. Conclusions Q.Clear is an iterative algorithm that improves significantly the quality of PET images compared to OSEM, increasing the SUVmax of findings (in particular for small findings) and the signal-to-noise ratio. However, due to the intrinsic characteristics of this algorithm, it will be necessary to adapt and/or modify the current interpretative criteria based of quantitative evaluation, to avoid an overestimation of the disease burden.

A case of clear cell sarcoma with BRAF mutation

( Soo Hyeon Bae ),( Hee Sun Lim ),( Jee Bum Lee ),( Seong Jin Kim ),( Seung Chul Lee ),( Young Ho Won ),( Sook Jung Yun ) 대한피부과학회 2015 대한피부과학회 학술발표대회집 Vol.67 No.1

Clear cell sarcoma (CCS) is a rare malignant tumor of tendon and aponeuroses involving the distal extremities of young adults. At times, histological examination alone is insufficient for complete diagnosis. The deep location along with t(12;22)(q12;q12) are the characteristic features distinguishing from metastatic melanoma. Also, whereas BRAF mutations are commonly found in cutaneous melanoma, it is rarely present in CCS. Herein, we report a rare case of CCS with positive BRAF mutation. A 71 year-old female presented with a deep-seated tender 2x2cm sized subcutaneous nodule on the medial side of the right sole which started only 8 months ago. Histopathology from excisional biopsy showed dermal tumor composed of bundles of spindle cells and epithelioid cells with clear cytoplasm, separated by thick fibrous tissue. Immunostains with Positive S-100 and HMB-45 were positive, and RT-PCR revealed EWSR1-ATF fusion gene. We made a diagnosis of CCS. Interestingly, we also detected BRAF mutation from the lesion by sequencing. Wide excision and radical lymph node dissection was performed after positive SLNB results with several lymph node (LN) invasions. Considering the fast clinical progression consisting of short term presentation with several LN metastasis, relatively poor outcome is expected in this patient. We present a rare case of CCS clear cell sarcoma with BRAF mutation, and we expect BRAF inhibitors can be considered in this case.

초분절 자질의 관점에서 살펴본 『동국정운(東國正韻)』 한자음의 ‘청·탁’에 대한 고찰

문성호(Moon, Sungho) 중앙어문학회 2021 語文論集 Vol.85 No.-

청·탁은 본래 음악 용어로 경중(輕重)·고하(高下)·심천(深淺)·음양(陰陽)으로 묘사되었고, 근대 이전까지 음악과 성운학에서 청·탁의 용어 사용은 큰 차이가 없었다. 칼그렌(Klas Bernhard Johannes Karlgren, 1889~1978)의 연구 이후 청·탁은 무성음과 유성음의 분절 자질로 분석되는데, 이 경우 음소문자인 훈민정음의 음운 자질이 설명되기 어렵다. 세종은 음악과 성운학의 전문가로 훈민정음을 창제했을 때, 청·탁을 분절 자질이 아닌 전통의 초분절 자질로 인식했을 것이라 생각된다. 이에 대한 근거로 『동국정운(東國正韻)』 한자음의 청·탁이 『광운(廣韻)』 41성류의 반절상자에 대응하고, 반절상자의 청·탁은 광동어의 초분절 자질인 음조와 양조에 대응하는 것을 들 수 있다. 청·탁을 음조와 양조의 관점에서 살필 경우, 훈민정음의 청·탁 표기가 체계적으로 설명이 된다. 본고에서는 청·탁을 공명강의 무게중심에 따라 달라지는 음색의 대비라는 관점에서 초분절 자질을 설명했다. 음색은 동양음악에서 가장 중요한 요소로 소리의 무게·높이·깊이가 종합적으로 갖추어질 때 하나의 음색이 형성된다. The qīngyīn (淸/clear) and zhuóyīn (濁/unclear) sounds, originally derived from musical terminology, were used from a hyper segmental perspective where qīngyīn denoted high notes, and zhuóyīn denoted low notes within the Chinese phonological field. There was barely any difference between Chinese phonological terms and musical terms before the modern era. However, after the research carried out by Klas Bernhard Johannes Karlgren (1889-1978), the qīngyīn and zhuóyīn sounds were analyzed as segmental phonemes chosen as a result of confrontations between voiced and unvoiced sounds. If we were to follow this reasoning, it would be very difficult to explain the phoneme quality of the Hunminjeongeum, which is a phonemic writing system. King Sejong was an expert in music and Chinese phonology and when he created the Hunminjeongeum, he must have perceived the qīngyīn and zhuóyīn sounds as the traditional hyper segmental phonemes instead of segmental phonemes. To prove this, the qīngyīn and zhuóyīn sounds of the Chinese character sounds in the Donggukjungwoon can be observed as corresponding with the 41 initial consonants of the first character in a fǎnqiè (反切) in the Guǎngyùn(廣韻). It is also possible to cite the fact that the qīngyīn and zhuóyīn sounds of the first character in a fǎnqiè corresponds with the yīndiào (陰調/high tones) and yángdiào (陽調/low tones), which are the hyper segmental phonemes of Cantonese.

염색체 검사에서 t(1222)(q1312)를 보인 투명 세포 육종

안지영 ( Ji Young Ahn ),김지은 ( Ji Eun Kim ),서성준 ( Seong Jun Seo ),김명남 ( Myeung Nam Kim ),홍창권 ( Chang Kwun Hong ),노병인 ( Byung In Ro ),송계용 ( Kye Yong Song ) 대한피부과학회 2005 대한피부과학회지 Vol.43 No.9

PET/CT SUV Ratios in an Anthropomorphic Torso Phantom

연준호(Joon-Ho Yeon),홍건철(Gun-Chul Hong),강병현(Byung-Hyun Kang),신예지(Ye-Ji Sin),오욱진(Uk-Jin Oh),윤혜란(Hye-Ran Yoon),홍성종(Seong-Jong Hong) 한국방사선학회 2020 한국방사선학회 논문지 Vol.14 No.1

표준섭취계수(SUV) PET과 영상 재구성 방법에 따라 크게 달라진다. 삼성 서울병원 핵의학과에 설치된 GE사의 Discovery MIDR와 Discovery Ste의 영상 재구성 알고리즘을 이용하여 의인화몸통팬텀 내의 심장, 간과 배경영역에서 표준섭취계수를 측정하여 실제 SUV와 비교하였다. 영상 재구성 알고리즘은 MIDR에서는 VPFX-S (TOF+PSF), QCFX-S-350 (Q.Clear+TOF+PSF), QCFX-S-50와 VPHD-S (OSEM+PSF), Ste에서는 VUE Point (OSEM)와 FORE-FBP를 사용하였다. 방사선사의 방사선 피폭을 감소시키기 위하여 소량의 ¹⁸F-FDG 선원을 물과 혼합하였다: 52.5 ml 심장에는 2.28 MBq, 1,290 ml 간에는 20.3 MBq와 9,590 ml 배경영역에는 45.7 MBq을 주입하였다. 심장에서의 표준섭취계수는 MIDR의 VPFX-S, QCFX-S-350, QCFX-S-50, VPHD-S와 Ste의 VUE Point (OSEM)와 FOR-FBP 알고리즘에서 각각 27.1, 28.0, 27.1, 26.5, 8.0와 7.4 이었으며, 기대치는 5.9이었다. 배경역역에서는 4.2, 4.1, 4.2, 4.1, 1.1와 1.2 이었으며, 기대치는 0.8이었다. 각 영역에서 표준섭취계수는 PET과 알고리즘에 따라 크게 차이가 있었지만, 심장과 배경영역의 SUV 비율은 비교적 일정하여 6개 영상 재구성 알고리즘에 대하여 6.5, 6.8, 6.5, 6.5, 7.3와 6.2 이었으며 기대치는 7.8이었다. 심장에서의 평균 신호 대 잡음비(SNR)는 각각 6개 알고리즘에 대하여 8.3, 12.8, 8.3, 8.4, 17.2와 16.6이었다. 결론적으로 PET 성능 평가는 각 영역에서의 절댓값 보다는 두 영역 사이의 SUV 비율이 적절하며, 비교적 소량의 방사능으로도 확인할 수 있는 가능성이 있다. The standard uptake values (SUVs) strongly depend on positron emission tomographs (PETs) and image reconstruction methods. Various image reconstruction algorithms in GE Discovery MIDR (DMIDR) and Discovery Ste (DSte) installed at Department of Nuclear Medicine, Seoul Samsung Medical Center were applied to measure the SUVs in an anthropomorphic torso phantom. The measured SUVs in the heart, liver, and background were compared to the actual SUVs. Applied image reconstruction algorithms were VPFX-S (TOF+PSF), QCFX-S-350 (Q.Clear+TOF+PSF), QCFX-S-50, VPHD-S (OSEM+PSF) for DMIDR, and VUE Point (OSEM) and FORE-FBP for DSte. To reduce the radiation exposure to radiation technologists, only the small amount of radiation source ¹⁸F-FDG was mixed with the distilled water: 2.28 MBq in the 52.5 ml heart, 20.3 MBq in the 1,290 ml liver and 45.7 MBq for the 9,590 ml in the background region. SUV values in the heart with the algorithms of VPFX-S, QCFX-S-350, QCFX-S-50, VPHD-S, VUE Point, and FOR-FBP were 27.1, 28.0, 27.1, 26.5, 8.0, and 7.4 with the expected SUV of 5.9, and in the background 4.2, 4.1, 4.2, 4.1, 1.1, and 1.2 with the expected SUV of 0.8, respectively. Although the SUVs in each region were different for the six reconstruction algorithms in two PET/CTs, the SUV ratios between heart and background were found to be relatively consistent; 6.5, 6.8, 6.5, 6.5, 7.3, and 6.2 for the six reconstruction algorithms with the expected ratio of 7.8, respectively. Mean SNRs (Signal to Noise Ratios) in the heart were 8.3, 12.8, 8.3, 8.4, 17.2, and 16.6, respectively. In conclusion, the performance of PETs may be checked by using with the SUV ratios between two regions and a relatively small amount of radioactivity.