Unfolding of differential energy spectra in the MAGIC experiment

The paper describes the different methods, used in the MAGIC experiment, to unfold experimental energy distributions of cosmic ray particles (gamma-rays). Questions and problems related to the unfolding are discussed. Various procedures are proposed which can help to make the unfolding robust and reliable. The different methods and procedures are implemented in the MAGIC software and are used in most of the analyses.Comment: Submitted to NIM

Comparison between 2D and 3D computed tomography evaluation of glenoid bone defect in unilateral anterior gleno-humeral instability

Obiettivo. Scopo del nostro lavoro \ue8 stato valutare la concordanza tra misurazioni bidimensionali (2D) e tridimensionali (3D) con tomografi a computerizzata (TC) nella identifi cazione delle dimensioni e del tipo di difetto osseo di glena nell\u2019instabilit\ue0 gleno-omerale anteriore. Materiali e metodi. Cento pazienti con instabilit\ue0 glenoomerale anteriore monolaterale hanno eseguito esame TC delle spalle. Le immagini sono state riformate sia con il metodo 2D (multi-planar reconstruction, MPR) che 3D (volume rendering technique, VRT). L\u2019area del difetto di glena \ue8 stata calcolata in confronto con la glena sana ed \ue8 stata espressa in percentuale. La concordanza tra le due misurazioni \ue8 stata valutata con il metodo Bland- Altman; una differenza media del 5% \ue8 stata considerata clinicamente signifi cativa. Risultati. L\u2019analisi della concordanza tra le misurazioni MPR e VRT della percentuale di glena mancante ha mostrato una differenza media di 0,62%\ub11,96%. La concordanza percentuale tra le due misurazioni nel valutare la grandezza del difetto osseo \ue8 stata del 97% (p<0,0001). La concordanza percentuale nel discriminare il tipo di difetto osseo \ue8 stata del 97% (p<0,0001). Conclusioni. La concordanza tra misurazioni TC 2D (MPR) e 3D (VRT) nell\u2019identifi care le dimensioni ed il tipo di difetto osseo di glena nell\u2019instabilit\ue0 glenoomerale anteriore \ue8 stata cos\uec alta da poterle considerare intercambiabili.Purpose. This study evaluated the agreement between 2D and 3D computed tomography (CT) measurements in identifying the size and type of glenoid-bone defect in anterior glenohumeral instability. Materials and methods. One hundred patients affected by unilateral anterior glenohumeral instability underwent a CT of both shoulders. Images were processed with both 2D [multiplanar reconstruction (MPR)] and 3D [volumerendering (VR)] methods. The area of the missing glenoid was calculated in comparison with the healthy glenoid and expressed as a percentage. Agreement between the two measurements was assessed according to the Bland-Altman method; a 5% mean difference was considered as clinically relevant. Results. Analysis of agreement between MPR and VR measurements of the percentage of missing glenoid showed a mean difference equal to 0.62%\ub11.96%. Percent agreement between the two measurements in detecting the presence of bone defect was 97% (p<0.0001). Percent agreement between the two measurements in discriminating the type of bone defect was 97% (p<0.0001). Conclusions. Agreement between 2D (MPR) and 3D (VR) CT measurements to identify the size and type of glenoid-bone defect in anterior glenohumeral instability was so high that the two measurements can be considered interchangeable