Whole-Body Diffusion-Weighted MRI Compared to 18 FFDG PET/CT in Initial Staging and Therapy Response Assessment of Hodgkin Lymphoma in Pediatric Patients.

PURPOSE: The aim of our study was to compare whole-body diffusion-weighted MRI (WB-DWI-MRI) to fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the assessment of initial staging and treatment response in pediatric patients with Hodgkin lymphoma. MATERIALS AND METHODS: This prospective study comprised 11 children with Hodgkin lymphoma. Whole-body DWI-MRI and FDG-PET/CT were obtained at baseline and after 2 cycles of chemotherapy. Two radiologists measured the apparent diffusion coefficient (ADC) values of the sites of involvement agreed upon in consensus and 1 nuclear medicine physician assessed the PET/CT. Reliability of radiologists' ratings was assessed by intraclass correlation coefficients (ICC2,1). The sensitivity and positive predictive value (PPV) of DW-MRI relative to PET/CT were calculated for nodal and extranodal sites. The patients were staged according to both modalities. Association of treatment responses was assessed through the Pearson correlation between the ADC ratios and the change standardized uptake value (SUV) between baseline and follow-up. RESULTS: There was good agreement between the raters for nodal and extranodal ADC measurements. The sensitivity and PPV of DW-MRI relative to PET/CT of nodal disease was 0.651 and 1.0, respectively, at baseline, and 0.697 and 0.885 at follow-up. The sensitivity and PPV of extranodal disease were 0.545 and 0.6 at baseline, and 0.167 and 0.333 at follow-up. Diffusion-weighted MRI determined correct tumor stage in 8 of 11 examinations. There was poor correlation between the ADC ratios and the absolute change in SUV between baseline and follow-up (0.348). CONCLUSION: Our experience showed that WB-DWI-MRI is inferior to PET/CT for initial staging and assessment of treatment response of Hodgkin lymphoma in pediatric patients.

Safe Use of Radium-223 Dichloride (223RaCl2) Across a Wide Range of Clinical Scenarios, Incorporating a 10-year Single-Institution Radiation Safety Experience.

Radium 223Ra dichloride (223RaCl2) is an effective therapeutic radiopharmaceutical presently approved for the treatment of prostate cancer metastatic to bone. It is unique by virtue of being the first alpha-emitting radiopharmaceutical to achieve approval for use in the clinic, reaching this status both in the United States and Europe in 2013. In over ten years of research and approved clinical usage, the authors have encountered very few radiation-safety incidents of concern with 223RaCl2; in this review, they relate their first-hand experience with this radiopharmaceutical and share some lessons learned, including situations of bleeding, surgery and patient demise. The authors first provide a basic review of the relevant physical properties of 223Ra and aspects of its radiobiology, followed by a discussion of the biodistribution of 223RaCl2, the radiopharmaceutical presently approved for clinical use. As would be expected from a primarily alpha emitter, external exposures to staff and family members from patients administered 223Ra are typically low in comparison with exposure from patients who have undergone other nuclear medicine procedures. There still remains potential for health care workers and family members to receive a significant internal exposure, through the ingestion of even minute amounts of activity, so proper handling practices are paramount.