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To propose a magnetic resonance imaging (MRI) quality assurance procedure that can be used for multicenter comparison of different MR scanners for quantitative diffusion-weighted imaging (DWI).Twenty-six centers (35 MR scanners with field strengths: 1T, 1.5T, and 3T) were enrolled in the study. Two different DWI acquisition series (b-value ranges 0-1000 and 0-3000 s/mm(2) , respectively) were performed for each MR scanner. All DWI acquisitions were performed by using a cylindrical doped water phantom. Mean apparent diffusion coefficient (ADC) values as well as ADC values along each of the three main orthogonal directions of the diffusion gradients (x, y, and z) were calculated. Short-term repeatability of ADC measurement was evaluated for 26 MR scanners.A good agreement was found between the nominal and measured mean ADC over all the centers. More than 80% of mean ADC measurements were within 5% from the nominal value, and the highest deviation and overall standard deviation were 9.3% and 3.5%, respectively. Short-term repeatability of ADC measurement was found2.5% for all MR scanners.A specific and widely accepted protocol for quality controls in DWI is still lacking. The DWI quality assurance protocol proposed in this study can be applied in order to assess the reliability of DWI-derived indices before tackling single- as well as multicenter studies.

Purpose The management of patients with CIED receiving radiotherapy (RT) is challenging and requires a structured multidisciplinary approach. In order to stratify the risk of patients and approaching RT sessions appropriately, a consensus document from Associazione Italiana Aritmologia e Cardiostimolazione (AIAC), Associazione Italiana Radioterapia Oncologica (AIRO), Associazione Italiana Fisica Medica (AIFM) has been published on the International Journal of Cardiology in 2018. Along this line, the AIFM working group is promoting specific measurements to better investigate the role of RT on CIED. Methods In Consensus document potential radiation interactions on CIED such as recommendations for the estimation of the dose to the device are described and a multidisciplinary review of in vivo and in vitro data is presented. Further, a multi-center study to evaluate IGRT dose, neutron contamination assessment, and photon out-of-field dose are still being performed. To measure out-of-field dose to CIEDs two phantoms were created and sent to centers working with different treatment planning systems (TPS). Results Preliminary results show that the use of daily CBCT can add a considerable contribution to CIED dose up to 50 cGy like lung 4D protocol. Neutron contamination of photon and electron beams of energies ranging from 6 to 18 MV measured with REM counters show that neutron production for 10 MV photon beam is not negligible. It confirms that neutron produced by electron beam has to be taken into account for beam energy higher than 15 MeV. Comparisons between calculated and measured out-of-filed dose along with examining the behavior of different dosimeters are being studied. Working group is performing measurement to confirm that, in absence of out-of-field TPS commissioning, in vivo dosimetry is still recommended in the case of short distance CIED-field edge or dose close to 2 Gy. Conclusions A detailed approach for safe management of RT patients with CIEDs is now available with important implications for clinical practice. Only a multidisciplinary approach between medical physicists, radiation oncologists and electrophysiologists can really reduce the risk of malfunctions in patient with CIED undergoing RT. Results of the AIFM working group try to provide valuable support and further indications in this regard.