title: Performance improvement of small gamma camera using NaI(Tl) plate and position sensitive photo-multiplier tubes.
abstract: The purpose of this study was to improve the performance of a small gamma camera, utilizing a NaI(Tl) plate and a 5" position sensitive PMT. We attempted to build a NaI(Tl) plate crystal system which retained all its advantages, while at the same time integrating some of the advantages inherent in an array-type scintillation crystal system. Flood images were obtained with a lead hole mask, and position mapping was performed by detecting hole positions in the flood image. Energy calibration was performed using the energy spectra obtained from each hole position. Flood correction was performed using a uniformity correction table containing the relative efficiency of each image element. The spatial resolution was improved about 16% after correction at the centre field of view. Resolution deterioration at the outer field of view (OFOV) was considerably ameliorated, from 6.7 mm to 3.2 mm after correction. The sensitivity at the OFOV was also increased after correction, from 0.7 cps microCi(-1) to 2.0 cps microCi(-1). The correction also improved uniformity, from 5.2% to 2.1%, and linearity, from 0.5 mm to 0 mm. The results of this study indicate that the revised correction method can be employed to considerably improve the performance of a small gamma camera using a NaI(Tl) plate-type crystal. This method also provides high spatial resolution and linearity, like array-type crystals do, while retaining the specific advantages of plate-type crystals.
authors.affiliation: Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-Ku, Seoul, 135-710, Korea.
authors.forename: Myung Hwan
authors.initials: MH
authors.lastname: Jeong
authors.forename: Yong
authors.initials: Y
authors.lastname: Choi
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Chung
authors.forename: Tae Yong
authors.initials: TY
authors.lastname: Song
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Jung
authors.forename: Key Jo
authors.initials: KJ
authors.lastname: Hong
authors.forename: Byung Jun
authors.initials: BJ
authors.lastname: Min
authors.forename: Yearn Seong
authors.initials: YS
authors.lastname: Choe
authors.forename: Kyung-Han
authors.initials: KH
authors.lastname: Lee
authors.forename: Byung-Tae
authors.initials: BT
authors.lastname: Kim
mesh_terms: D004582:Electronics, Medical; D004867:Equipment Design; D019544:Equipment Failure Analysis; D015902:Gamma Cameras; D007089:Image Enhancement / Q000295:instrumentation*; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D011877:Radionuclide Imaging / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012974:Sodium Iodide / Q000528:radiation effects*; D014159:Transducers
chemical_list: D012974:Sodium Iodide