Objiective To compare the diagnostic value of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT and ⁹⁹Tc^m-methylene diphosphonic acid (⁹⁹Tc^m-MDP) SPECT whole body bone scan in detecting of multiple myeloma bone disease (MBD).

Methods The retrospective study enrolled 18 male and 11 female multipe myeloma (MM) patients, aged 39-81 years (mean, 60.14±10.41 years) and clinically diagnosed from April 2015 to May 2018 in Anqing hospital affiliated to Anhui medical university. ¹⁸F-FDG PET/CT and ⁹⁹Tc^m-MDP SPECT were performed two weeks apart, and χ² test was used in comparing abnormal bone changes detected by ¹⁸F-FDG PET/CT and ⁹⁹Tc^m-MDP SPECT.

Results ¹⁸F-FDG PET/CT and ⁹⁹Tc^m-MDP SPECT accurately diagnosed 28 and 21 MM patients, respectively. Eighteen patients were focal, one patient was diffuse, and nine patients were mixed on the ¹⁸F-FDG PET/CT images. Twenty-one MM patients were found single, that is, multiple bones accumulated the agent abnormally on ⁹⁹Tc^m-MDP SPECT images. The positive match rate of ¹⁸F-FDG PET/CT and ⁹⁹Tc^m-MDP SPECT were 96.6% (28/29) and 72.4% (21/29), respectively. The differences between the sensitivities of the two methods were significant.

Conclusion The results indicate that ¹⁸F-FDG PET/CT is more sensitive than ⁹⁹Tc^m-MDP SPECT in detecting MBD in patients with MM and has a significant diagnostic value for bone marrow involvement and extramedullary disease.