title: Phantom study on radiotherapy planning using PET/CT--delineation of GTV by evaluating SUV.
abstract: We assessed the usefulness of PET/CT images to determine the target volume in radiotherapy planning by evaluating the standardized uptake value (SUV). We evaluated the imaging conditions and image-reconstruction conditions of PET/CT useful for treatment planning by collecting (18)F-FDG images of acrylic spheres (10-48 mm in diameter) in a phantom. The (18)F-FDG concentration in the spheres was 10-fold higher than that of the phantom. The contours were delineated according to the SUV by the threshold and regions of interest (ROI) methods. Comparisons of two- and three-dimensional (2D and 3D) acquisition images indicated that the sharpness and quantitative qualities of the sphere boundaries were better in the former than in the latter. In the extraction of outlines using the SUV, outlines obtained at an SUV of 40-50% of the maximum agreed well with the actual acrylic sphere size. 2D acquisition images are more suitable for delineating target volume contours, although 3D acquisition images are more popular in diagnostic imaging. An SUV of 40-50% of the maximum is suggested to be appropriate for GTV contouring of sphere tumors with homogenously distributed (18)F-FDG.
authors: Department of Radiology, Takai Hospital, Nara 632-0006, Japan. nag01736@nifty.ne.jp
authors: Fumiaki
authors: F
authors: Uto
authors: Eiji
authors: E
authors: Shiba
authors: Seiitchi
authors: S
authors: Onoue
authors: Hitoshi
authors: H
authors: Yoshimura
authors: Mami
authors: M
authors: Takada
authors: Yoshihiko
authors: Y
authors: Tsuji
authors: Satoshi
authors: S
authors: Fukugami
authors: Isao
authors: I
authors: Asakawa
authors: Tetsuro
authors: T
authors: Tamamoto
authors: Masatoshi
authors: M
authors: Hasegawa
mesh_terms: D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics*; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008863:Microspheres; D015588:Observer Variation; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D014057:Tomography, X-Ray Computed
chemical_list: D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18