355. The Acoustic Noise in RM

Abstract

Purpose This work originates from our experience about RM acoustic noise in the same RM sites as advisor of local authorities and in a specific 1,5T implant. Methods Different limits and reference levels are considered for the protection of people’s health as defined by WHO: at first for workers’auditory effect descending from the 89/391/EEC directive. When RM noise interferes with other employees &/or civil people DPCM14/11/1997 and local regulation have taken account. E.G. when LeqA reference levels (25 dBA at night or 35dBA (from 6am to10pm, window-closed) are overcome, a 3 dB differential limit can be considered at night or 5 dB during the day. In adjacent working places, to take account of non-auditory safety effects as the speech interference, UNI EN ISO 11690-1 levels can be considered; E.g: 55dBA for report room and 65dBA for control room assimilated respectively to a single office or an open space. To assess the risk and to select suitable protections for patient and workers in RM room, data as Leq, Lpeak (C and A weighted, Z unweighted) and noise spectrum are necessary in specific points. For measurements in a 1,5T magnet room, integrator phonometer coupled with an experimental optic microphone has been used. The tested points are. I) Left ear patient, near isocenter bore; II) front entry bore, at laser cross; III) 50 cm from point II; IV) near the entry door. The adjacent spaces were measured by condenser microphones according technical rules. Results A timely noise assessment led to reconsider some project. In one case the planned reporting room has had moved after measures. 89/391/EEC auditory limits can’t be overcome outside the 1,5T magnet room examined; inside it, high LZpeak for many sequences and acceptable level for “silent” sequences according literature were found. The optic microphone used is RM compliance and suitable for size and band frequency, but saturated at 111 dB(Z) and the results were unweighted. Conclusions Graphical Abstract View Large Image Figure Viewer Download Hi-res image This work originates from our experience about RM acoustic noise in the same RM sites as advisor of local authorities and in a specific 1,5T implant. Different limits and reference levels are considered for the protection of people’s health as defined by WHO: at first for workers’auditory effect descending from the 89/391/EEC directive. When RM noise interferes with other employees &/or civil people DPCM14/11/1997 and local regulation have taken account. E.G. when LeqA reference levels (25 dBA at night or 35dBA (from 6am to10pm, window-closed) are overcome, a 3 dB differential limit can be considered at night or 5 dB during the day. In adjacent working places, to take account of non-auditory safety effects as the speech interference, UNI EN ISO 11690-1 levels can be considered; E.g: 55dBA for report room and 65dBA for control room assimilated respectively to a single office or an open space. To assess the risk and to select suitable protections for patient and workers in RM room, data as Leq, Lpeak (C and A weighted, Z unweighted) and noise spectrum are necessary in specific points. For measurements in a 1,5T magnet room, integrator phonometer coupled with an experimental optic microphone has been used. The tested points are. I) Left ear patient, near isocenter bore; II) front entry bore, at laser cross; III) 50 cm from point II; IV) near the entry door. The adjacent spaces were measured by condenser microphones according technical rules. A timely noise assessment led to reconsider some project. In one case the planned reporting room has had moved after measures. 89/391/EEC auditory limits can’t be overcome outside the 1,5T magnet room examined; inside it, high LZpeak for many sequences and acceptable level for “silent” sequences according literature were found. The optic microphone used is RM compliance and suitable for size and band frequency, but saturated at 111 dB(Z) and the results were unweighted.