title: Performance Evaluation of a New Dedicated Breast PET Scanner Using NEMA NU4-2008 Standards.
abstract: The aim of this work was to evaluate the performance characteristics of a newly developed dedicated breast PET scanner, according to National Electrical Manufacturers Association (NEMA) NU 4-2008 standards.
  
  
  METHODS
  The dedicated breast PET scanner consists of 4 layers of a 32 × 32 lutetium oxyorthosilicate-based crystal array, a light guide, and a 64-channel position-sensitive photomultiplier tube. The size of a crystal element is 1.44 × 1.44 × 4.5 mm. The detector ring has a large solid angle with a 185-mm aperture and an axial coverage of 155.5 mm. The energy windows at depth of interaction for the first and second layers are 400-800 keV, and those at the third and fourth layers are 100-800 keV. A fixed timing window of 4.5 ns was used for all acquisitions. Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated in accordance with NEMA NU 4-2008 standards. Human imaging was performed in addition to the evaluation.
  
  
  RESULTS
  Radial, tangential, and axial spatial resolution measured as minimal full width at half maximum approached 1.6, 1.7, and 2.0 mm, respectively, for filtered backprojection reconstruction and 0.8, 0.8, and 0.8 mm, respectively, for dynamic row-action maximum-likelihood algorithm reconstruction. The peak absolute sensitivity of the system was 11.2%. Scatter fraction at the same acquisition settings was 30.1% for the rat-sized phantom. Peak noise-equivalent counting rate and peak true rate for the ratlike phantom was 374 kcps at 25 MBq and 603 kcps at 31 MBq, respectively. In the image-quality phantom study, recovery coefficients and uniformity were 0.04-0.82 and 1.9%, respectively, for standard reconstruction mode and 0.09-0.97 and 4.5%, respectively, for enhanced-resolution mode. Human imaging provided high-contrast images with restricted background noise for standard reconstruction mode and high-resolution images for enhanced-resolution mode.
  
  
  CONCLUSIONS
  The dedicated breast PET scanner has excellent spatial resolution and high sensitivity. The performance of the dedicated breast PET scanner is considered to be reasonable enough to support its use in breast cancer imaging.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Kanae K
authors.initials: KK
authors.lastname: Miyake
authors.affiliation: Department of Radiological Technology, Kyoto College of Medical Science, Kyoto, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Matsumoto
authors.affiliation: Department of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan; and.
authors.forename: Mika
authors.initials: M
authors.lastname: Inoue
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan ynakamo1@kuhp.kyoto-u.ac.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakamoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Kanao
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Tae
authors.initials: T
authors.lastname: Oishi
authors.affiliation: Department of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan; and.
authors.forename: Shigeto
authors.initials: S
authors.lastname: Kawase
authors.affiliation: Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan.
authors.forename: Keishi
authors.initials: K
authors.lastname: Kitamura
authors.affiliation: Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Yamakawa
authors.affiliation: Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Akazawa
authors.affiliation: Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Ohi
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000818:Animals; D001940:Breast / Q000000981:diagnostic imaging*; D006801:Humans; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000592:standards*; D011786:Quality Control; D051381:Rats; D012015:Reference Standards; D012542:Scattering, Radiation
keywords: NEMA; breast cancer; dedicated breast PET; performance evaluation