Nuclear Medicine Techniques in Pediatric Bone Imaging

Abstract

An important mandate when imaging pediatric patients is the reduction of radiation exposure to the lowest possible level consistent with good quality diagnostic imaging, so individual selection of radiopharmaceutical dosage and imaging technique is essential. Although the logistics of image acquisition and the approach to interpretation mirror the more common use in adults, the challenges of imaging young children typically require greater attention to patient preparation, positioning, and supervision during imaging, with the use of parental or family engagement in the procedure, gentle restraint, and occasionally the need for sedation. Because the normal bone scan appearance varies dramatically with age as osseous structures mature, it is critical that the interpreting physician be well versed in the range of normal variability at each developmental stage. Although routinely employed in the evaluation of malignancy, radionuclide bone imaging in children is used for a much wider range of benign disorders than it is typical in adults. In many pediatric nuclear medicine departments, the evaluation of benign bone disorders represents most imaging procedures. Common indications include the evaluation of sports injuries, osteomyelitis, trauma, including suspected child abuse, growth disorders, such as mandibular condyle asymmetry, and noninfectious processes such as Langerhans cell histiocytosis. Both planar scintigraphy and SPECT imaging are widely employed, although the SPECT acquisition time presents a barrier in some age groups, making shorter planar spot views desirable when feasible. PET bone imaging with ¹⁸F-sodium fluoride has been shown useful in a number of pediatric disorders, but may present issues in young children, as it can require the use of sedation. Despite this challenge, the higher resolution and resulting better anatomical depiction of bone anatomy by PET techniques can be very valuable in evaluating small structures, and current experience suggests a large future role for fluoride PET imaging.