EANM/ESC guidelines for radionuclide imaging of cardiac function.

Radionuclide imaging of cardiac function represents a number of well-validated techniques for accurate determination of right (RV) and left ventricular (LV) ejection fraction (EF) and LV volumes. These first European guidelines give recommendations for how and when to use first-pass and equilibrium radionuclide ventriculography, gated myocardial perfusion scintigraphy, gated PET, and studies with non-imaging devices for the evaluation of cardiac function. The items covered are presented in 11 sections: clinical indications, radiopharmaceuticals and dosimetry, study acquisition, RV EF, LV EF, LV volumes, LV regional function, LV diastolic function, reports and image display and reference values from the literature of RVEF, LVEF and LV volumes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "prevailing or general consensus". The guidelines are designed to assist in the practice of referral to, performance, interpretation and reporting of nuclear cardiology studies for the evaluation of cardiac performance.

(99m)Tc-rituximab radiolabelled by photo-activation: a new non-Hodgkin's lymphoma imaging agent.

PURPOSE: Rituximab was the first chimeric monoclonal antibody to be approved for treatment of indolent B-cell non-Hodgkin's lymphoma (NHL). It is directed against the CD20 antigen, which is expressed by 95% of B-cell NHLs. The aim of this study was to explore the possibility of radiolabelling rituximab with (99m)Tc for use as an imaging agent in NHL for early detection, staging, remission assessment, monitoring for metastatic spread and tumour recurrence, and assessment of CD20 expression prior to (radio)immunotherapy. METHODS: Rituximab was purified from Mabthera solution (Roche), photo-activated at 302 nm by UV irradiation and radiolabelled with (99m)Tc. The effectiveness of the labelling method was evaluated by determination of the number of free thiol groups per photoreduced antibody, radiochemical purity and in vitro stability of (99m)Tc-rituximab. RESULTS: On average, 4.4 free thiol groups per photoreduced antibody were determined. Radiolabelling yields greater than 95% were routinely observed after storage of the photo-activated antibody at -80 degrees C for 195 days. The direct binding assay showed preserved ability of (99m)Tc-rituximab to bind to CD20, with an average immunoreactive fraction of 93.3%. The internalisation rate was proven to be low, with only 5.3% of bound (99m)Tc-rituximab being internalised over 4 h at 37 degrees C. CONCLUSION: Our results demonstrate that (99m)Tc-rituximab of high radiochemical purity and with preserved binding affinity for the antigen can be prepared by photoreduction and that the method shows good reproducibility. (99m)Tc-rituximab will be further explored as an imaging agent applicable in NHL for the purposes mentioned above.