Clinical Study Can Na 18 F PET/CT Be Used to Study Bone Remodeling in the Tibia When Patients Are Being Treated with a Taylor Spatial Frame? Henrik Lundblad, 1 Gerald Q. Maguire Jr., 2 Henrik Olivecrona, 1 Cathrine Jonsson, 3 Hans Jacobsson, 1 Marilyn E. Noz, 4 Michael P. Zeleznik, 5 Lars Weidenhielm, 1 and Anders Sundin 1 1 Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institute, A2:07, 171 76 Stockholm, Sweden 2 School of Information and Communication Technology, KTH Royal Institute of Technology, Isaordsgatan 26, 418 164-40 Stockholm, Sweden 3 Department of Hospital Physics, Karolinska University Hospital, 17 176 Solna, Stockholm, Sweden 4 Department of Radiology, New York University, 550 First Avenue, THW232, New York, NY 10016, USA 5 School of Computing, College of Engineering, University of Utah, 50 Central Campus Dr., Room 3190, Salt Lake City, UT 84112, USA Correspondence should be addressed to Marilyn E. Noz; marilyne.noz@gmail.com Received 9 January 2014; Accepted 16 February 2014; Published 19 March 2014 Academic Editors: C.-H. Kao and Y. Lu Copyright © 2014 Henrik Lundblad et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Monitoring and quantifying bone remodeling are of interest, for example, in correction osteotomies, delayed fracture healing pseudarthrosis, bone lengthening, and other instances. Seven patients who had operations to attach an Ilizarov-derived Taylor Spatial Frame to the tibia gave informed consent. Each patient was examined by Na 18 F PET/CT twice, at approximately six weeks and three months aſter the operation. A validated soſtware tool was used for the following processing steps. e first and second CT volumes were aligned in 3D and the respective PET volumes were aligned accordingly. In the first PET volume spherical volumes of interest (VOIs) were delineated for the crural fracture and normal bone and transferred to the second PET volume for SUV max evaluation. is method potentially provides clinical insight into questions such as, when has the bone remodeling progressed well enough to safely remove the TSF? and when is intervention required, in a timelier manner than current methods? For example, in two patients who completed treatment, the SUV max between the first and second PET/CT examination decreased by 42% and 13%, respectively. Further studies in a larger patient population are needed to verify these preliminary results by correlating regional Na 18 F PET measurements to clinical and radiological findings. 1. Introduction Circular frames, such as the Ilizarov-derived Taylor Spa- tial Frame (TSF), with the ability to correct deformity in six dimensions have added new possibilities to treat diffi- cult orthopaedic conditions [1–3]. Complex open fractures, malunions, infected nonunions, and severe deformities are all examples of conditions where the circular frame has enabled limb salvage as opposed to amputation [4–6]. Despite the obvious advantages of being able to gradually correct deformity, without having to go back to the operating theater, circular frames are currently mainly reserved for more complex conditions. In these cases, it is common that patients undergo TSF treatment for more than 12 months. Apart from the inconvenience of bearing a bulky external fixator this long, the treatment may be painful; there is a risk of opioid addiction and possible psychosocial and occupational problems for the patient. erapy using a TSF is performed according to a treat- ment schedule, which is a set of daily instructions for Hindawi Publishing Corporation e Scientific World Journal Volume 2014, Article ID 249326, 9 pages http://dx.doi.org/10.1155/2014/249326