Early experience with fluorine-18 sodium fluoride bone PET in young patients with back pain

Purpose: Skeletal positron emission tomography (PET) with fluorine-18 (F-18) sodium fluoride (F-18 NaF) is an alternative to technetium-99m (Tc-99m)methylene diphosphonate (MDP) scintigraphy. Experience with pediatric PET is sparse, primarily in oncology. This study assesses the role of F-18 NaF in evaluating young patients with back pain. Methods: Ninety-four F-18 NaF PET scans were performed in 94 patients (27 males, 67 females; mean age, 15 years; range, 4-26 years) with back pain. Three-dimensional PET acquisition was performed 30 minutes after administration of F-18 NaF (2.1 MBq/kg; maximum, 148 MBq). Radiation doses are presented for F-18 NaF and Tc-99m MDP. Results: F-18 NaF PET revealed a possible cause of back pain in 55% (52/94). Fifteen patients had 2 or more potential sources of back pain. Diagnoses by PET were pars interarticularis/pedicle stress (34%), spinous process injury (16%), vertebral body ring apophyseal injury (14%), stress at a transitional vertebra-sacral articulation (7%), and sacroiliac joint inflammation/stress (3%). Comparing F-18 NaF PET with Tc-99m MDP scintigraphy, time between injection and scanning was shorter (0.5 hours vs 3 hours), radiation dosimetry was similar (3.5 mGy vs 2.8 mGy effective dose for a 55-kg patient for F-18 NaF and Tc-99m MDP, respectively), and cost of radiopharmaceutical was higher. Conclusions: F-18 NaF bone PET can detect a variety of skeletal abnormalities in young patients with back pain. Relative to Tc-99m MDP, images are of higher resolution. Total time from tracer administration to completion is shorter, and radiation dosimetry is similar. Higher cost for F-18 NaF may be offset by enhanced patient throughput.