OpenDose: Open-Access Resource for Nuclear Medicine Dosimetry.

Radiopharmaceutical dosimetry depends on the localization in space and time of radioactive sources and requires the estimation of the amount of energy emitted by the sources deposited within targets. In particular, when computing resources are not accessible, this task can be performed using precomputed tables of specific absorbed fractions (SAFs) or S values based on dosimetric models. The aim of the OpenDose collaboration is to generate and make freely available a range of dosimetric data and tools. Methods: OpenDose brings together resources and expertise from 18 international teams to produce and compare traceable dosimetric data using 6 of the most popular Monte Carlo codes in radiation transport (EGSnrc/EGS++, FLUKA, GATE, Geant4, MCNP/MCNPX, and PENELOPE). SAFs are uploaded, together with their associated statistical uncertainties, in a relational database. S values are then calculated from monoenergetic SAFs on the basis of the radioisotope decay data presented in International Commission on Radiological Protection Publication 107. Results: The OpenDose collaboration produced SAFs for all source region and target combinations of the 2 International Commission on Radiological Protection Publication 110 adult reference models. SAFs computed from the different Monte Carlo codes were in good agreement at all energies, with SDs below individual statistical uncertainties. Calculated S values were in good agreement with OLINDA/EXM 2.0 (commercial) and IDAC-Dose 2.1 (free) software. A dedicated website (www.opendose.org) has been developed to provide easy and open access to all data. Conclusion: The OpenDose website allows the display and downloading of SAFs and the corresponding S values for 1,252 radionuclides. The OpenDose collaboration, open to new research teams, will extend data production to other dosimetric models and implement new free features, such as online dosimetric tools and patient-specific absorbed dose calculation software, together with educational resources.

Total THA in adult osteonecrosis related to sickle cell disease.

UNLABELLED: Most previous studies of THA in sickle cell disease report high risks of medical and orthopaedic complications, including infections and a higher incidence of failure than observed after THA for osteonecrosis related to other conditions. Based on our experience (1245 orthopaedic procedures during the last 25 years), we questioned these conclusions and retrospectively reviewed 312 arthroplasties performed in 244 patients with sickle cell disease. The mean age of the 126 women and 118 men at the time of surgery was 32 years. The minimum followup was 5 years (mean, 13 years; range, 5-25 years). We revised 10 hips (3%) for infection at a mean 11 years (range, 7-15 years) after the primary procedure and revised 21 cups (8%) and 17 stems (5%) for aseptic loosening at a mean of 14 years. We observed medical complications after 85 operations (27%) and orthopaedic complications in 42 cases (13%). Although THA carries a high risk of complication in patients with sickle cell disease, the benefits for the patient are substantial, and the risk of revision for loosening or infection appeared less than described in previous literature. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.