Journal of the Korean Society of Radiology (한국방사선학회논문지)

The Korean Society of Radiology (한국방사선학회)
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Evaluation of Standardized Uptake Value applying Prompt Gamma Correction on 68Ga-DOTATOC PET/CT Image

68Ga-DOTATOC PET/CT에서 Prompt Gamma Correction을 적용한 SUV의 평가

  • Yoon, Seok Hwan (Department of Nuclear Medicine, Seoul National University Hospital)
  • 윤석환 (서울대학교병원 핵의학과)
  • Received : 2017.11.21
  • Accepted : 2018.02.28
  • Published : 2018.02.28
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Abstract

$^{68}Ga$ was eluted from a $^{68}Ge/^{68}Ga$ radionuclide generator. $^{68}Ga$ decays into $^{68}Zn$, with a half life=67.8min. The decay is 88.9 % by ${\beta}$+ and 11.1 % by EC. The main ${\beta}$+ decay (87.7 %) is to the ground level of $^{68}Zn$ and it is a pure positron emission branch. A small fraction decays ${\beta}$+ (1.2 %) into an excited level of $^{68}Zn$, which promptly decays into the ground level with a ${\gamma}$ (1.077 Mev). This can constitute prompt gamma contamination in the PET data, if the 1.077 Mev ${\gamma}$ has a scatter interaction in the patient, and generates a lower energy ${\gamma}$ in coincidence with the positron annihilation pair. The purpose of this study was to evaluate standardized uptake value(SUV) before and after applying prompt gamma rays correction on $^{68}Ga$-DOTATOC PET/CT image. Fifty patient underwent PET/CT 1 hour after injection of the $^{68}Ga$-DOTATOC. The SUVmax and SUVmean of lesions and normal tissues (Pituitary, Lung, Liver, Spleen, Kidney, Intestine) were evaluated before and after applying prompt gamma correction on $^{68}Ga$-DOTATOC PET/CT image. Additionally, the SUVmax of each lesions and SUVmean of the soft tissues were measured on images. and target to background ratios (TBR) were calculated as quantitative indices. Among 15 patients, 25 of lesions (Pancreas, Liver, Thoracic Spine, Brain) with increased uptake on $^{68}Ga$-DOTATOC PET/CT image. SUVmax and SUVmean were increased in lesion site and normal tissue after prompt gamma rays correction. TBR was $51.51{\pm}49.28$ and $55.50{\pm}53.12$ before and after prompt gamma rays correction, respectively. (p<0.0001)

$^{68}Ga$ 방사성 핵종은 $^{68}Ge/^{68}Ga$ 제너레이터에서 생산되는 양전자 방출핵종으로서 PET 검사에 이용되는 방사성 핵종이다. $^{68}Ga$은 67.8분의 반감기를 가지고 88.9 %의 ${\beta}$+ 붕괴와 11.1 %의 전자포획으로 $^{68}Zn$으로 붕괴된다. ${\beta}$+ 붕괴 과정에서 87.7 %는 기저상태의 $^{68}Zn$로 붕괴되며, 1.2 %는 여기상태의 $^{68}Zn$로 붕괴된다. 여기상태의 $^{68}Zn$은 1.077 Mev의 ${\gamma}$선을 방출하며 기저상태의 $^{68}Zn$가 된다. 이때 방출되는 1.077 Mev의 ${\gamma}$선을 Prompt Gamma라 하며, Prompt Gamma-ray가 환자와 상호작용하게 되면 저에너지 ${\gamma}$선의 산란선이 발생되게 되는데 이 산란선이 PET의 동시계수 회로에 검출되어 질 수 있다. 이 연구의 목적은 $^{68}Ga$을 이용하는 PET검사 중 신경내분비 종양진단에 사용되는 $^{68}Ga$-DOTATOC PET/CT영상에 Prompt Gamma-ray 보정 전 후의 표준섭취계수(SUV)를 평가해 보고자 하였다. $^{68}Ga$-DOTATOC PET/CT를 시행한 15명의 환자에 대해서 병변부위(Pancreas, Liver, Thoracic Spine, Brain)와 정상으로 섭취되는 조직(Pituitary, Lung, Liver, Spleen, Kidney, Intestine)의 SUVmax와 SUVmean을 비교하였으며, 임상영상의 정량적 평가를 위해 Target to Background Ratio(TBR)을 산출하여 비교하였다. Prompt Gamma-ray 보정 후 Thoracic Spine을 제외한 병변부위와 Pituitary를 제외한 정상조직에서 SUVmax, SUVmean은 높은 값을 나타내었으며, TBR은 Prompt Gamma-ray 보정 전 후 각각 $51.51{\pm}49.28$, $55.50{\pm}53.12$로 보정 후 높은 값을 나타냈다. (p<0.0001)

Keywords

References

  1. Putzer D., Kroiss A., Waitz D., Gabriel M., Traub- Weidinger T, Uprimny C, von Guggenberg E, Decris toforo C, Warwitz B, Widmann G, Virgolini IJ, "So matostatin receptor PET in neuroendocrine tumours: 68Ga-DOTA0,Tyr3-octreotide versus 68Ga-DOTA0- lanreotide," European Journal of Nuclear Medicine and Molecular Imaging, Vol. 40, No. 3, pp. 364-372, 2013. https://doi.org/10.1007/s00259-012-2286-6
  2. Ali Afshar-Oromieh, Maya B. Wolf, Clemens Kratochwil, Frederik L. Giesel, Stephanie E. Combs, Antonia Dimitrakopoulou-Strauss, Regula Gnirs, Matthias C. Roethke, Heinz P. Schlemmer, Uwe Haberkorn, " Comparison of 68Ga-DOTATOC-PET/CT and PET/MRI hybrid systems in patients with cranial meningioma: Initial results," Neuro oncology, Vol. 17, No. 2, pp. 312-319, 2015. https://doi.org/10.1093/neuonc/nou131
  3. Maurizio Conti, Lars Eriksson, "Physic of pure and non-pure positron emitters for PET: a review and a discussion," European Journal of Nuclear Medicine and Molecular Imaging Physics, Vol. 3, No. 1, pp. 1- 17, 2016.
  4. Abella M1, Alessio AM, Mankoff DA, MacDonald LR, Vaquero JJ, Desco M, Kinahan PE, "Accuracy of CT-based attenuation correction in PET/CT bone imaging," Physics in Medicine & Biology, Vol. 57, No. 9, pp. 2477-2490, 2012. https://doi.org/10.1088/0031-9155/57/9/2477
  5. Buchmann I, Henze M, Engelbrecht S, Eisenhut M, Runz A, Schafer M, Schilling T, Haufe S, Herrmann T, Haberkorn U, "Comparison of 68Ga-DOTATOC P ET and 111In-DTPAOC (Octreoscan) SPECT in patients with neuroendocrine tumors," European Journal o f Nuclear Medicine and Molecular Imaging, Vol. 34, No. 10, pp. 1617-1626, 2007. https://doi.org/10.1007/s00259-007-0450-1
  6. Benjamin Noto, Florian Buther, Katharina Auf der Springe, Nemanja Avramovic, Walter Heindel, Michael Schafers, Thomas Allkemper, Lars Stegger, "Impact of PET acquisition durations on image quality and lesion detectability in whole-body 68Ga-PSMA PET-MRI," European Journal of Nuclear Medicine and Molecular Imaging Research, Vol, 7 No.1, pp. 1-12, 2017.
  7. Jing Tang, Arman Rahmim, Riikka Lautamaki, Martin A Lodge, Frank M Bengel, Benjamin M, W Tsui, "Optimization of Rb-82 PET acquisition and reconstruction protocols for myocardial perfusion defect detection," Physics in Medicine & Biology, Vol. 54, No. 10, pp. 3161-3171, 2009. https://doi.org/10.1088/0031-9155/54/10/013
  8. Hong I, Rothfuss H, Fürst S, "Prompt Gamma Correction for Ga-68 PSMA PET studies," San Diego: presented at IEEE Nuclear Science Symposium and Medical Imaging Conference, 2015.
  9. Gaertner FC, Beer AJ, Souvatzoglou M, Eiber M, Furst S, Ziegler SI, "Evaluation of feasibility and image quality of 68Ga-DOTATOC positron emission tomography/magnetic resonance in comparison with positron emission tomography/computed tomography in patients with neuroendocrine tumors," Investigative Radiology, Vol. 48, No. 5, pp. 263-272, 2013. https://doi.org/10.1097/RLI.0b013e31828234d0
  10. JM Jeong, YJ Kim, YS Lee, DS Lee, JK Chung, MC Lee, "Radio labeling of NOTA and DOTA with Positron Emitting 68Ga and Investigation of In Vitro Properties," Nuclear Medicine and Molecular Imaging, Vol. 43, No. 4, pp. 330-336, 2009.