title: A visual grading study for different administered activity levels in bone scintigraphy.
abstract: BACKGROUND
  The aim of the study is to assess the administered activity levels versus visual-based image quality using visual grading regression (VGR) including an assessment of the newly stated image criteria for whole-body bone scintigraphy.
  
  
  METHODS
  A total of 90 patients was included and grouped in three levels of administered activity: 400, 500 and 600 MBq. Six clinical image criteria regarding image quality was formulated by experienced nuclear medicine physicians. Visual grading was performed in all images, where three physicians rated the fulfilment of the image criteria on a four-step ordinal scale. The results were analysed using VGR. A count analysis was also made where the total number of counts in both views was registered.
  
  
  RESULTS
  The administered activity of 600 MBq gives significantly better image quality than 400 MBq in five of six criteria (P<0·05). Comparing the administered activity of 600 MBq to 500 MBq, four criteria of six show significantly better image quality (P<0·05). The administered activity of 500 MBq gives no significantly better image quality than 400 Mbq (P<0·05). The count analysis shows that none of the three levels of administrated activity fulfil the recommendations by the EANM.
  
  
  CONCLUSIONS
  There was a significant improvement in perceived image quality using an activity level of 600 MBq compared to lower activity levels in whole-body bone scintigraphy for the gamma camera equipment end set-up used in this study. This type of visual-based grading study seems to be a valuable tool and easy to implement in the clinical environment.
authors.affiliation: Department of Medical Physics, IMH, Linköping University, Radiation Physics UHL, County council of Östergötland, Östergötland, Sweden.
authors.forename: Agnetha
authors.initials: A
authors.lastname: Gustafsson
authors.forename: Henrik
authors.initials: H
authors.lastname: Karlsson
authors.forename: Kerstin A
authors.initials: KA
authors.lastname: Nilsson
authors.forename: Håkan
authors.initials: H
authors.lastname: Geijer
authors.forename: Anna
authors.initials: A
authors.lastname: Olsson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging / Q000379:methods*; D019275:Radiopharmaceuticals / Q000008:administration & dosage*; D015203:Reproducibility of Results; D013669:Technetium Tc 99m Medronate / Q000008:administration & dosage / Q000031:analogs & derivatives*; D014796:Visual Perception; D051598:Whole Body Imaging
chemical_list: D019275:Radiopharmaceuticals; C024226:technetium Tc 99m hydroxymethylene diphosphonate; D013669:Technetium Tc 99m Medronate
keywords: bone and bones; evaluation; radionuclide imaging; technetium Tc 99 m