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

Skeletal positron emission tomography (PET) with fluorine-18 (18F) sodium fluoride (18F NaF) is an alternative to technetium-99m (99mTc)methylene diphosphonate (MDP) scintigraphy. Experience with pediatric PET is sparse, primarily in oncology. This study assesses the role of 18F NaF in evaluating young patients with back pain.

Ninety-four 18F 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 18F NaF (2.1 MBq/kg; maximum, 148 MBq). Radiation doses are presented for 18F NaF and 99mTc MDP.

18F 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 18F NaF PET with 99mTc 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 18F NaF and 99mTc MDP, respectively), and cost of radiopharmaceutical was higher.

18F NaF bone PET can detect a variety of skeletal abnormalities in young patients with back pain. Relative to 99mTc MDP, images are of higher resolution. Total time from tracer administration to completion is shorter, and radiation dosimetry is similar. Higher cost for 18F NaF may be offset by enhanced patient throughput.