PET/CT 검사에서 호흡에 따른 인공산물을 줄이기 위한 Average CT의 유용성

• 영문명: Evaluation of Average CT to Reduce the Artifact in PET/CT
• 발행기관: 대한핵의학기술학회
• 저자명: 김정선(Jung Sun Kim) 남기표(Ki Pyo Nam) 박승용(Seung Yong Park) 류재광(Jae Kwang Ryu) 차민경(Min Kyeong Cha)
• 간행물 정보: 『핵의학기술』Vol.14 No.1, 3~7쪽, 전체 5쪽
• 주제분류: 의약학 > 방사선과학
• 파일형태: PDF
• 발행일자: 2010.06.30

영문 초록

Purpose: The usefulness of Positron Emission Tomography (PET) images in diagnosis, staging, recurrent and treatment response evaluation has already been known. However, tumors which are small size, located in lower lobe of lung or upper lobe of liver are shown misalignment, distortion and different Standard Uptake Value (SUV) by respiration in PET images. Therefore, if radiotherapy based on normal respiration, it may cause low treatment response or more side effects because targets which had to treat, out of treat range or over dose to normal tissue. The purpose of this study is to evaluate attenuation-correction with Average CT (ACT) for more accuracy SUV measurement and minimize artifact by respiration. Materials and Methods: 13 patients, who had tumors which are around the diaphragm, underwent ACT scan after Helical CT (HCT) scan with PET/CT (Discovery DSTE 8; GE Healthcare). We quantified the differences between attenuation corrected image with HCT and attenuation corrected image with ACT in artifact size and maximum SUV (SUVₘₐₓ). Artifacts were evaluated by measurement of the curved photogenic area in the lower thorax of the PET images for all patients. SUVₘₐₓ was measured separately at the primary tumors. Analysis program was Advantage Workstation v4.3 (GE Healthcare). Patients were injected with 7.4 MBq (0.2 mCi) per kg of ¹⁸F-FDG and scanned 1 hour after injection. The PET acquisition was 3 minute per bed. Results: Significantly lower artifact were observed in PET/ACT images than in PET/HCT images (below-thoracic artifacts caused by under corrected 1.5±3.5 cm vs. 13.4±4.2 cm). Significantly higher SUVₘₐₓ were noted in PET/ACT images than in PET/HCT images in the primary tumor. Compared with PET/HCT images, SUVₘₐₓ in PET/ACT images were higher by 5.3±3.9% (mean value) tumor. The highest difference was observed in Lower lobe of lung (7.7 to 8.7; 13%). Conclusion: Due to its significantly reduced artifacts in lower thoracic, attenuation corrected image with ACT images provided more reliable SUVₘₐₓ and may be helpful in monitoring treatment response. Moreover, ACT can separate upper lobe of liver and lower lobe of lung, it may be helpful in interpretation. ACT will be clinically useful, considering increased dose caused by ACT scan and adapt.

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실험재료 및 방법

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키워드

Respiratory motion artifacts Averaged CT Attenuation correction