title: Quantitative renography with the organ volume method and interporative background subtraction technique.
abstract: When quantification of renal activity is performed by planar imaging, many correction factors must be considered. To obtain quantitative renal images and renogram, we have examined our proposed method by using the organ volume for scatter, attenuation, and background activity, and the interporative background subtraction (IBS) technique in phantom and clinical studies. A renal phantom study was performed by varying the renal depth from 3 to 11 cm and the kidney-to-background activity concentration ratio from 5 to 80. Planar images were properly corrected for scatter, attenuation and background activity by our method and the corrected images were compared with the images obtained by the conventional method for the estimation of true renal activity. Clinical Tc-99m DTPA dynamic data for both a good and a poor renal function were also corrected by our method and volume-corrected renograms were obtained. For the phantom study, depth-independent images were obtained and these images gave a good estimation of the true count rate. In the clinical study, the conventional renogram was especially modified to allow for oversubtraction of background counts in the early phase (0-4 min). In conclusion, our proposed correction method can assess renal function qualitatively and quantitatively in both static and dynamic planar renal imaging.
authors.affiliation: Department of Radiology, Kumamoto University School of Medicine, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kojima
authors.forename: Y
authors.initials: Y
authors.lastname: Takaki
authors.forename: A
authors.initials: A
authors.lastname: Tsuji
authors.forename: R
authors.initials: R
authors.lastname: Nakashima
authors.forename: M
authors.initials: M
authors.lastname: Kira
authors.forename: M
authors.initials: M
authors.lastname: Hara
authors.forename: S
authors.initials: S
authors.lastname: Tomiguchi
authors.forename: M
authors.initials: M
authors.lastname: Matsumoto
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D005069:Evaluation Studies as Topic; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging*; D007677:Kidney Function Tests / Q000379:methods; D019047:Phantoms, Imaging; D011866:Radioisotope Renography / Q000379:methods*; D013382:Subtraction Technique; D016284:Technetium Tc 99m Pentetate
chemical_list: D016284:Technetium Tc 99m Pentetate