Original article A prospective study of DWI, DCE-MRI and FDG PET imaging for target delineation in brachytherapy for cervical cancer Kathy Han a,b,⇑ , Jennifer Croke a,b , Warren Foltz b , Ur Metser c,d , Jason Xie a , Tina Shek a , Brandon Driscoll a , Cynthia Ménard a,b,e , Doug Vines a,b , Catherine Coolens a,b , Anna Simeonov a,b , Akbar Beiki-Ardakani a,b , Eric Leung a,b , Wilfred Levin a,b , Anthony Fyles a,b , Michael F. Milosevic a,b a Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto; b Department of Radiation Oncology, University of Toronto; c Joint Department of Medical Imaging, University Health Network, Toronto; d Department of Medical Imaging, University of Toronto; and e Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, Canada article info Article history: Received 12 April 2016 Received in revised form 1 August 2016 Accepted 2 August 2016 Available online xxxx Keywords: Diffusion-weighted MRI Dynamic contrast-enhanced MRI FDG PET Cervical cancer Brachytherapy Target delineation abstract Background and purpose: We examined the utility of dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted MRI (DWI), and FDG-PET imaging for brachytherapy target delineation in patients with locally advanced cervical cancer. Materials and methods: Twenty-two patients had DWI, DCE-MRI, and FDG-PET/CT scans after brachyther- apy applicator insertion, in addition to standard T2-weighted (T2w) 3T MRI. Gross tumor volume (GTV B ) and high-risk clinical target volume (HRCTV) were contoured first on T2w images, and then modified if indicated upon review of DWI/DCE-MRI/FDG-PET images by two observers. The primary endpoint was utility, determined by the number of patients whose volumes were modified, and interobserver variabil- ity. Results: Eleven patients’ T2w-GTV B were modified based on DWI/DCE-MRI/FDG-PET by observer 1, due to clearer demarcation (7) and residual disease not well visualized on T2w MRI (4). GTV B was modified in 17 patients by observer 2 (11 and 6, respectively). Incorporation of functional imaging improved the confor- mity index (CI) for GTV B from 0.54 (T2w alone) to 0.65 (P = 0.003). HRCTV was modified in 3 and 8 patients by observers 1 and 2, respectively, with a trend toward higher CI using functional imaging (0.71 to 0.76, P = 0.06). Conclusions: DWI/DCE-MRI/FDG-PET imaging as a supplement to T2w MRI decreased interobserver vari- ability in GTV B delineation. Ó 2016 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology xxx (2016) xxx–xxx The standard treatment of locally advanced cervical cancer con- sists of external beam radiotherapy (EBRT), concurrent chemother- apy, and brachytherapy. Image-guided adaptive brachytherapy has yielded higher local control and survival rates compared to histor- ical control [1–4]. Many centers have adopted the GEC-ESTRO recommendations for brachytherapy target delineation, where T2-weighted (T2w) MRI remains the gold standard for tumor visu- alization [5,6]. Despite this, recent studies using T2w MRI reported significant uncertainties in brachytherapy target delineation, and poor interobserver variability with mean conformity indices (CI) of only 0.58–0.60 for gross tumor volume at brachytherapy (GTV B ), and 0.39–0.79 (mostly between 0.70–0.79) for high-risk clinical target volume (HRCTV) [7–11]. Functional imaging by diffusion-weighted MRI (DWI) and dynamic contrast-enhanced MRI (DCE-MRI) in combination with conventional T2w MRI can improve cervical tumor distinction [12–15]. DWI displays information about water mobility in tissue, tissue cellularity, and integrity of cellular membranes [12]. Tumors usually exhibit restricted diffusion. DCE-MRI measures temporal changes in MR signal intensity associated with intravenous injection of an extracellularly confined contrast agent, reflecting variations in tissue perfusion, extracellular space fraction, microvascular permeability, and angiogenesis [16]. Small cervical tumors usually enhance homogeneously and earlier than the normal cervical stroma, whereas large tumors are often non- enhancing (necrotic) and surrounded by an enhancing rim [12]. http://dx.doi.org/10.1016/j.radonc.2016.08.002 0167-8140/Ó 2016 Elsevier Ireland Ltd. All rights reserved. ⇑ Corresponding author at: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada. E-mail address: Kathy.Han@rmp.uhn.on.ca (K. Han). Radiotherapy and Oncology xxx (2016) xxx–xxx Contents lists available at ScienceDirect Radiotherapy and Oncology journal homepage: www.thegreenjournal.com Please cite this article in press as: Han K et al. A prospective study of DWI, DCE-MRI and FDG PET imaging for target delineation in brachytherapy for cer- vical cancer. Radiother Oncol (2016), http://dx.doi.org/10.1016/j.radonc.2016.08.002