INDICE. ISSN PERIODICO TECNICO-SCIENTIFICO DELLE PROFESSIONI SANITARIE Volume 1, Numero 1-4, Dicembre 2012

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1 OFFICIAL JOURNAL ISSN PERIODICO TECNICO-SCIENTIFICO DELLE PROFESSIONI SANITARIE Volume 1, Numero 1-4, Dicembre 2012 INDICE Editoriale 3 Healthcare Professional Journal e Fondazione Progenies in sinergia G. Brusadin Articoli originali 5 Positive and negative effects of perceived inequity in Italian healthcare workers: the role of social support M. Vignoli, D. Guglielmi, S. Simbula, M. Depolo 17 Valutazione dell esposizione del tecnico sanitario di radiologia medica al campo magnetico statico in risonanza magnetica F. Coelli, D. Ravanelli, A. Valentini Articoli di revisione 31 Integrazione Ospedale-Territorio: un servizio socio-sanitario M. Di Muzio, S. Dell Edera 39 Sistemi digitali: analisi valutativa sui potenziali aumenti di dose da dose creep e saturazione dei rivelatori M. Doronzo, R. Terlizzi, W. Antonucci, E. Marrone, A. Alemanno Comunicazione breve 47 Radiochemical purity and stability of 99m Tc-HMPAO preparations: the influence of ph, volume recovery, and storage conditions A.L. Viglietti, G. Perlo, C. Augeri, C. Massara, S. Zaccaria, L. Uccelli, A. Boschi Note tecniche 53 Principali artefatti in PET/TC: ruolo del tecnico sanitario di radiologia medica nella loro individuazione e limitazione M.P. Natale, V. Frascolla, D.P. Siani 59 Recensione 61 Indice degli Autori - 1 -

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3 Healthcare Professional Journal Vol.1, N. 1-4, 2012 Editoriale Healthcare Professional Journal e Fondazione Progenies in sinergia Egregi Lettori, come Direttore Responsabile di Healthcare Professional Journal sono lieto di inaugurare con questo numero le uscite con periodicità regolare della rivista. Come in tutte le attività i risultati si raggiungono perché c è un team di persone che con impegno e passione vi dedica il proprio tempo. Ed è per questo che in modo, forse irrituale, ma assolutamente dovuto che inizio questo editoriale con i ringraziamenti. Ringrazio in primis la Fondazione Progenies ed il suo Consiglio Direttivo che ha creduto nel progetto e sostiene la realizzazione di HPJ avendo adottato la rivista come suo organo ufficiale ad integrazione della promozione della ricerca scientifica e della formazione delle Professioni Sanitarie. Ringrazio gli Autori degli articoli che hanno affidato i loro lavori al severo processo di revisione inter pares ed hanno accettato di collaborare alla modifica ed integrazione dei contenuti al fine di migliorare la qualità della informazione offerta ai Lettori. Ringrazio tutto l Editorial Board per aver messo, e mettere, con grande generosità la propria rimarchevole competenza professionale nell accurato lavoro di revisione ed accreditamento scientifico dei contenuti proposti. Approfitto, in questo punto, per dare il benvenuto nella squadra alla Collega Roberta Fulgenzi che mi affiancherà nella direzione della rivista e che darà un importante apporto ed un rinnovato punto di vista derivante dal proprio background di professionista infermiere. Ringrazio la redazione della rivista per l enorme lavoro che svolge con un più che puntale lavoro di revisione tecnica degli articoli volto a migliorare la fruibilità degli stessi in termini di leggibilità e di forma dei contenuti. I lavori che offriamo alla attenzione dei Lettori sono particolarmente in linea con la mission della rivista ma anche con le finalità statutarie della Fondazione Progenies. I lavori possono essere trasmessi anche in lingua inglese per rendere più accessibili i contenuti in ambito internazionale. E proprio in lingua inglese è l originale ed interessante primo articolo che propone, supportata da una rigorosa raccolta ed analisi di dati, una prospettiva di gestione delle risorse umane che può ridurre il burn out degli operatori sanitari migliorandone l engagement. Il secondo lavoro presentato indaga, presentando dati di rilevazioni effettuate, l esposizione al campo magnetico degli operatori TSRM presso l unità di risonanza magnetica, un fattore di rischio professionale ancora incerto in termini di esiti clinici ma che in futuro assumerà sempre maggiore definizione dalla migliore comprensione degli effetti biologici della esposizione a campi magnetici migliaia di volte superiore a quello terrestre. Il terzo lavoro è un importante revisione bibliografica che pone il focus sui modelli di integrazione dell assistenza sanitaria sul territorio, tematica centrale per la sostenibilità del sistema salute con una popolazione che, fortunatamente, è sempre più longeva. Sempre un attenta revisione bibliografica è invece il quarto lavoro Corrispondenza: Dr. Gianfranco Brusadin, Centro di Riferimento Oncologico (CRO) IRCCS, via Franco Gallini, Aviano (PN), tel , gianfrancobrusadin@hpjournal.org, Healthcare Professional Journal 2012; 1 (1-4): 3-4. ISSN: Articolo ricevuto in redazione in data 14 dicembre Copyright 2012 by new Magazine edizioni s.r.l., Trento, Italia, Tutti i diritti riservati

4 HPJ e Fondazione Progenies in sinergia G. Brusadin presentato che pone l attenzione sul ruolo ed il contributo che i Tecnici di Radiologia, tramite una conoscenza approfondita della tecnologia disponibile, possono dare in termini di riduzione della dose di radiazioni erogata al paziente mantenendo al contempo prestazioni ottimali in termini di iconografia ottenibile. Una comunicazione breve nell ambito medico-nucleare è il quinto lavoro che fornisce delle indicazioni utili per garantire la stabilità e la purezza radiochimica nella preparazione di kit per l esecuzione di esami con traccianti radioattivi. Sempre in ambito medico-nucleare è l ultima nota tecnica che vuole fornire degli spunti per migliorare la qualità iconografica delle immagini. I lavori presentati danno evidenza della trasversalità del pubblico dei lettori cui HPJ si rivolge, con l intento di essere il più possibile veicolo di diffusione di conoscenza scientifica per basare sempre di più la pratica professionale sull evidenza. Molti altri articoli sono in fase di revisione ma voglio concludere questo editoriale esortando tutti i Professionisti della Salute a sottoporre i propri lavori per la pubblicazione approfittando di questa nuova e concreta opportunità di condivisione ed accreditamento della propria esperienza lavorativa e di ricerca col fine ultimo di migliorare la qualità dell assistenza alla Persona malata. GIANFRANCO BRUSADIN Direttore Responsabile Healthcare Professional Journal - 4 -

5 Healthcare Professional Journal Vol.1, N. 1-4, 2012 Original Article Positive and negative effects of perceived inequity in Italian healthcare workers: the role of social support M. VIGNOLI, D. GUGLIELMI*, S. SIMBULA**, M. DEPOLO Department of Psychology, University of Bologna, Italy * Department of Science Education, University of Bologna, Italy ** Department of Psychology, University of Milano-Bicocca, Italy SUMMARY: OBJECT. The aim of this research was to investigate the existing relationships and key related variables in the Italian health-care system. Although many studies have examined perceived inequity in workplace contexts, indicating job burnout as a main consequence, little research has focused on the moderator variable of this relationship. Here we also analyse whether or not perceived inequity could affect not only employee burnout but also positive outcomes such as engagement. We also set out to determine whether social support could moderate the relationship between the perceived inequity and the outcomes considered (burnout and engagement); and whether the work sector (public or private) and social support moderate the relationship between the perceived inequity and the outcomes considered. PARTICIPANTS AND METHODS. 200 health care professionals, including social workers, medical practitioners and nurses, working in two different contexts, a public and a private hospital, were recruited for the study. All participants completed a questionnaire designed to evaluate perceived inequity, burnout, engagement and social support, under the supervision of our research team. RESULTS. The results demonstrate that perceived inequity affects the two main components of burnout (emotional exhaustion, β = 0.371, p = 0.000; cynicism β = 0.181, p = 0.011) but has no significant influence on employee engagement with their work. However buffer analysis shows that the interaction between perceived inequity and social support does have a partial effect on job burnout (emotional exhaustion β = 0.151, R 2 = 0.023, p = 0.021; personal accomplishment β = , R 2 = 0.046, p = 0.002) and a considerable influence on job engagement (vigour β = , R 2 = 0.068, p = 0.000; dedication β = , R 2 = 0.06, p = 0.000; absorption β = , R 2 = 0.057; p= 0.001). No evidence was found for the work sector buffer effect. CONCLUSIONS. Our findings add further insight to the field of perceived inequity in health-care contexts, and could support leaders charged with managing human resources in both the public and private sectors. KEY WORDS: Buffer effect, Burnout, Engagement, Perceived inequity, Social support. Effetti positivi e negativi della percezione di iniquità negli operatori sanitari italiani: il ruolo del supporto sociale RIASSUNTO: OBIETTIVO DELLO STUDIO. Esaminare le variabili principali e le relazioni esistenti nei contesti sanitari. Molti studi hanno indagato la percezione di iniquità dei professionisti sanitari e hanno individuato il burnout come conseguenza principale. Tuttavia sono presenti pochi studi che abbiano focalizzato la propria attenzione sulle variabili che moderano questo tipo di relazione. In questa ricerca verranno prese in considerazione anche le conseguenze positive, analizzando se la percezione di iniquità possa influire non solo sul burn- Correspondence: Dr. Michela Vignoli, Department of Psychology, University of Bologna, viale Berti Pichat 5, Bologna (Bo), Italy, ph. (+39) , fax (+39) , michela.vignoli@unibo.it Healthcare Professional Journal 2012; 1 (1-4): ISSN: Articolo ricevuto in redazione in data 12 marzo Copyright 2012 by new Magazine edizioni s.r.l., Trento, Italia, Tutti i diritti riservati

6 Positive and negative effects of perceived inequity in Italian healthcare workers M. Vignoli SIGLE: SD = Standard Deviation; JDCS = Job Demand-Control-Support; M = Mean; MBI = Maslach Burnout Inventory; MBI-GS = Maslach Burnout Inventory General Survey; SPSS = Statistical Package for Social Science. out ma anche sull engagement. Pertanto si ipotizza che: la percezione di iniquità incida sul burnout e sull engagement in tutte le proprie dimensioni; il supporto sociale moderi la relazione tra la percezione di iniquità e gli esiti considerati (burnout e engagement); il settore (pubblico o privato) moderi la relazione tra percezione di iniquità e gli esiti considerati. PARTECIPANTI E METODI. Lo studio ha coinvolto 200 lavoratori ed è composto da operatori socio-sanitari, medici e infermieri che operano in due differenti contesti, un ospedale pubblico e uno privato. Durante l incontro con i ricercatori i partecipanti hanno risposto ad un questionario che valutava la percezione di iniquità, il burnout, l engagement e il supporto sociale. RISULTATI. I risultati mostrano che la percezione di iniquità influisce sulle due dimensioni principali del burnout (esaurimento emotivo β = 0,371, p = 0,000; disaffezione lavorativa β = 0,181, p = 0,011), mentre non ha un impatto sull engagement. Tuttavia la moderazione mostra che l interazione tra la percezione di iniquità e il supporto sociale ha un influenza parziale sul burnout (esaurimento emotivo β = 0,151, R 2 = 0,023, p = 0,021; senso di riuscita professionale β = - 0,215, R 2 = 0,046, p = 0,002) e totale sull engagement (vigore β = - 0,261, R 2 = 0,068, p = 0,000; dedizione β = - 0,246, R 2 = 0,06, p = 0,000; assorbimento β = - 0,239, R 2 = 0,057; p = 0,001). Il settore nel quale operano i lavoratori non influenza le relazioni indagate. CONCLUSIONI. I nostri risultati aumentano la conoscenza sulla percezione di iniquità nel settore sanitario. Inoltre possono supportare i dirigenti nella gestione delle risorse umane sia nel settore pubblico che nel settore privato. PAROLE CHIAVE: Moderazioni, Burnout, Engagement, Percezione di iniquità, Supporto sociale. INTRODUCTION AND LITERATURE REVIEW EQUITY THEORY Equity and social exchange are key workplace variables that have been studied by psychologists and social scientists since the 1960s. The classic equity theory was developed by Adams (1), who claimed that inequity exists for a person whenever he perceives that the ratio of his outcomes to inputs and the ratio of others outcomes to others inputs are inequal. Indeed, individuals tend to maintain an equitable ratio between the inputs and the outputs involved in the exchange relationship. Furthermore, according to Festinger (9), A- dams postulates that when a person perceives a relationship as inequitable, he or she experiences a level of stress that is proportional to the perceived magnitude of inequity. Subsequently, Pritchard (24) added that the personal internal standard could be a yardstick to determine the level of perceived equity in the ratio between investments and rewards. Past experiences and the value attributed to investments would create such a personal internal standard. Inequity is a variable that has often been investigated in health-care contexts, because a lack of reciprocity is an intrinsic feature of caregiving relationships. In fact due to the intrinsic nature of their work, professional caregivers are constantly requires to take care of patients, to assist and rehabilitate them, and give them support, while the other parties in the relationship, the patients, are merely required to receive this attention, without obligation to give anything in exchange. As Truchot and Deregard (35) state, professional caregivers could therefore perceive a lack of reciprocity in their relations with their patients, leaving them particularly prone to negative outcomes such as burnout. NEGATIVE AND POSITIVE OUTCOMES OF PERCEIVING INEQUITY AT WORK: BURNOUT AND ENGAGEMENT A large body of research has demonstrated that perceived equity influences many important work-related variables. Nevertheless, researchers have tended to focus their efforts on negative outcomes rather than positive ones, in particular the relationship between perceived inequity and burnout, lack of organizational commitment, absenteeism, turnover intention, employee theft and lowered self-esteem (26,31). The most studied outcome of perceived inequity, burnout, has been distilled into three essential components: emotional exhaustion, cynicism and low sense of accomplishment. Emotional exhaustion is the central component of burnout, and the afflicted feel psychologically drained - this is the factor most strongly related to employee stress and wellbeing. Emotional exhaus

7 Healthcare Professional Journal Vol.1, N. 1-4, 2012 tion is generally accompanied by cynicism - a general attitude of indifference and emotional distance from work - and a sense of low personal accomplishment, characterized by a feeling of inadequacy and a lack of confidence in personal occupational success (18). Perceived inequity and its negative consequences have been studied in many professional caregiving roles, such as nurses (26), general practitioners (39), medical residents (23), medical specialists (30) and human service professionals (38). Although a few of these studies have investigated the relationship between perceived inequity and burnout in different exchange relationships (30,36), they have tended to focus on the component of emotional exhaustion (26,36,38). Indeed, only a small body of research has investigated positive equity outcomes such as job (21) or pay satisfaction (33). To expand this body of work we set out to investigate the relationship between perceived inequity and both positive and negative personal work outcomes (i.e., job engagement and burnout, respectively). To quote Gonzàlez-Romà et al., job engagement is a multidimensional construct defined as a positive, fulfilling, work-related state of mind that is characterized by vigour, dedication and absorption. Vigour is characterized by high levels of energy and mental resilience while working, the willingness to invest effort in one s work, and persistence even in the face of difficulties. Dedication is characterized by a sense of significance, enthusiasm, inspiration, pride and challenge. Absorption is characterized by fully concentrating on and being deeply engrossed in one s work, where time passes quickly and one has difficulty detaching oneself from work (10). WHAT INFLUENCES PERCEIVED INEQUITY AND ITS OUTCOMES? Studies conducted on personnel with different caregiving roles, namely nurses (41), social workers (35) and general practitioners (34), find that communal orientation (a personality characteristic that refers to the desire to give benefits in response to the perceived needs of others) has an interactive effect with perceived inequity on burnout, which was more pervasive in workers who reported low communal orientation. We propose that other constructs linked to perceived equity and outcomes, namely social support, the tangible and intangible support a person receives from other people, may also contribute to this relationship. Indeed, social support is strongly inversely correlated to perceived inequity within social exchange models, and is known to produce wellbeing in a person when offered within a relationship characterized by an equitable exchange of resources (11). Social support is also a key variable in the JDCS model (15), whose basic assumption is that social support mitigates the negative impact of high demand on strain. Moreover the availability of social support, as well as its receipt, may influence the individual s coping strategy, having obvious consequences on the outcome of such coping mechanisms (22). Indeed, a study by Nahum-Shani and Bamberger (19) finds that the buffering effect of social support on the relationship between demands and employee wellbeing varies as a function of the exchange relationship between an employee and his/her close support providers. Researchers also suggest that when suitably deployed, social support can moderate the potentially negative effects of a workplace stressor (32). Other studies have investigated the relationship between perceived inequity and social support. Van Dierendonck and colleagues (37), for example, studied social support as a moderator in the context of a burnout intervention programme. They found that the availability of social resources plays a crucial role in the effect of the programme on the equity perceived in the relationship with the employer organization. In fact, workers reporting higher social support from colleagues and supervisors also perceived high equity compared with workers who reported lower social support. A few studies have also investigated another variable that could affect behaviours in workplace contexts: public or private ownership. Aryee (3) states that public sector organizations are subject to several external entities that could produce conflicts in goals and increased pressures for accountability. To respond to the demands of the external entities, public sector organizations tend to be highly structured, with greater procedural standardization and hence greater bureaucratization. Private sector organizations, on the other hand, have to respond mainly to market demands. The competitive dynamic nature of this setting and the relative freedom from external entities and government monitoring yield a lower degree of bureaucratization. Public and private sector organizations are also regulated differently, meaning that leaders have different kinds of resources for managing public or private workers. For instance, in private organizations it is far easier to reward worker performance through a diverse range of benefits (i.e., economic gains, higher hierarchical status, etc.), managerial levers that promote a perception of equity. In a public setting, however, where leaders have fewer opportu

8 Positive and negative effects of perceived inequity in Italian healthcare workers M. Vignoli nities to give extrinsic rewards for performance, and to differentiate among workers in general, it is more likely that individuals will perceive less equity in the relationship between what they give to their work and what their work gives them back. Despite this evident disparity, few studies have investigated the differences between public and private settings as regards employee burnout and wellbeing, and reports in the literature are somewhat contradictory. For example Hansung (13) finds that public childwelfare workers experience higher levels of depersonalization and lower levels of personal accomplishment than private workers, whereas Macklin, Smith and Dollard (16), using the JDCS model, found no differences between public and private workers in their level of psychological distress. In order to shed more light on this issue, we set out to investigate whether there is any difference between the public and the private sector that could affect the relationship between perceived inequity and the outcomes considered. AIM AND HYPOTHESES The aim of the study was to investigate the relationship between perceived inequity and personal outcomes (both positive and negative) in health-care contexts. To achieve this we postulated that perceived inequity could lead not only to negative outcomes such as burnout (26,31) but also to positive outcomes, namely engagement, as follows: H1) Perceived inequity has an impact on all components of burnout; H2) Perceived inequity has an impact on all dimensions of engagement. Social support is strongly inversely correlated to perceived inequity because it is able to produce wellbeing, especially when it occurs within an equitable exchange of resources (11). We accordingly hypothesized that: H3) Social support can moderate the relationship between perceived inequity and all components of burnout; specifically, negative implications of inequity will be reduced when combined with high levels of social support; H4) Social support can moderate the relationship between perceived inequity and all components of engagement; in particular, negative implications of inequity will be reduced when combined with high levels of social support. Since the literature about differences between public and private sector reports contradictory results, we also set out to ascertain whether working within the private or the public sector influences this kind of relationship, hence: H5) Work sector and social support can moderate the relationship between perceived inequity and all components of burnout; in particular, public workers will report higher levels of burnout, as an outcome of the interaction between perceived inequity and social support; H6) Work sector and social support can moderate the relationship between perceived inequity and all the dimensions of engagement; in particular, public workers will report lower levels of engagement, as an outcome of the interaction between perceived inequity and social support. METHOD SAMPLE/PARTICIPANTS. Data were collected in two different employment settings, namely a public and a private hospital, both located in the same northern Italian region (Italian regions may have different laws on health care). Their employees participated voluntarily in this study, which was part of a project on wellbeing at work, commissioned by a group of healthcare companies. Meetings were held in both institutions to decide on the best manner in which to recruit participants, who were then asked to respond to a structured questionnaire in a meeting with the researcher. The final sample (N = 200) comprised 118 public and 82 private employees, specifically nurses (53%), social workers (23%) and medical practitioners (24%). Most of the workers involved were women (69.2% in total), and the ages reported by the respondents, categorized into 5 ranges, were well distributed: 13% of the respondents were years old, 37.3% were 31-40, 32% were 41-50, 16.1% were and 1.6% were over 60. A total of 25.8% of them had been working in the health-care sector for less than 5 years, 20% for 6-10 years, 20.7% for years and 33.5% for more than 16 years. Table 1 shows the different employee characteristics in the two hospitals. MEASURES. All the variables were investigated using quantitative methods. The scale reliability ranges from 0.66 to Except for cynicism, all the alpha values met the threshold of 0.70 (20). PERCEIVED INEQUITY. As in past research, we considered perceived inequity as an outcome of an imbalance between the personal internal standard and - 8 -

9 Healthcare Professional Journal Vol.1, N. 1-4, 2012 Gender Age (years) Work Experience (years) Role M F > 60 < > 16 Nurses Soc. W. Pract. Public Private Table 1. Descriptive statistics (N = 200). Note: all values are reported as percentages. Legend: F = females; M = males; Pract. = Practitioners; Soc. W. = Social Workers. Tabella 1. Statistiche descrittive (N = 200). Nota: tutti i valori sono percentuali. Legenda: F = femmine; M = maschi; Pract. = medici; Soc. W. = operatori socio-sanitari. the ratio between investments and gains (30). We used a five-point Likert scale - from 1 (never) to 5 (often) - to score the general inequity that a worker perceives in their own job (40,12). BURNOUT. We considered three components of burnout: emotional exhaustion, cynicism and personal accomplishment. Emotional exhaustion and personal accomplishment were assessed using the Maslach Burnout Inventory (17,29), and cynicism was measured using the MBI-GS (5,27). All the items relating to burnout were scored on a seven-point scale ranging from 0 (never) to 6 (always). ENGAGEMENT. The short version of the Utrecht Work Engagement Scale (4,25) was used to measure perceived engagement, specifically vigour, dedication and absorption. All items relating to engagement were scored on a seven-point scale ranging from 0 (never) to 6 (always). SOCIAL SUPPORT. We used eight items from Karasek s four-point scale (6,14), in which responses range from 1 (strongly disagree) to 4 (strongly agree). DATA ANALYSIS. SPSS version 14.0 was used to analyse the data. Hierarchical moderated regressions were used to test the proposed hypotheses. As a first step, the main effects, - perceived inequity and social support - were entered. In step 2, the twoway interactions of perceived inequity and social support were introduced. In step 3, the work sector (private or public hospital) was entered as a dummy. In step 4, two interactions involving public/private settings were introduced (perceived inequity public/private, and social support public/private), and in the final step, the three-way interactions were considered (perceived inequity social support public/private). All the variables were mean-centred (2). RESULTS Table 2 presents the descriptive statistics (M and SD) and correlations between variables. Perceived in- Variables Item M SD Perceived inequity (0.72) 2. Emotional exhaustion ** (0.89) 3. Cynicism ** 0.486** (0.66) 4. Personal accomplishment ** ** (0.75) 5. Vigor ** ** 0.460** (0.81) 6. Dedication ** ** 0.379** 0.728** (0.84) 7. Absorption ** ** 0.388** 0.630** 0.738** (0.73) 8. Social support ** ** ** 0.232** 0.208** 0.246** 0.227** (0.75) Table 2. Descriptive statistics and Cronbach s Alpha (N = 200). Legend: M = Mean; SD = Standard Deviation; * = p < 0.05; ** = p < 0.01; *** = p < Tabella 2. Statistiche descrittive e Alpha di Cronbach (N = 200). Legenda: M = Media; SD = deviazione standard; * = p < 0.05; ** = p < 0.01; *** = p <

10 Positive and negative effects of perceived inequity in Italian healthcare workers M. Vignoli Emotional Exhaustion Cynicism Personal Accomplishment Vigor Dedication Absorption Step 1: Main Effects Perceived Inequity 0.371*** 0.181* Social Support * *** 0.250** 0.204** 0.242** 0.234** R *** 0.136*** 0.059** 0.053** 0.058** 0.052** Step 2: Two-way interaction Perceived Inequity x Social 0.151* ** *** *** ** Support R * ** 0.068*** 0.060*** 0.057** Step 3: Sector Sector (public = 1) 0.132* ** R * ** Step 4: Two way interaction of sector Perceived Inequity x Sector Social Support x Sector R Step 5: Three way interaction Perceived Inequity x Social Support x Public Sector R Table 3. Moderate hierarchical regression (N = 200). Legend: R 2 = the variation of R 2 (the coefficient of determination R 2 is the proportion of variability in a data set that is accounted for by a statistical model)* = p < 0.05; ** = p < 0.01; *** = p < Tabella 3.Regressioni gerarchiche moderate (N=200). Legenda: R 2 = la variazione di R 2 (il coefficiente di determinazione R 2 è la proporzione di variabilità in un insieme di dati che viene rappresentato da un modello statistico); * = p < 0.05; ** = p < 0.01; *** = p < equity was found to be positively correlated to the main components of burnout (emotional exhaustion and cynicism), but no correlation was found between perceived inequity and potential positive outcomes such as personal accomplishment and job engagement. As expected, perceived social support was negatively correlated with perceived inequity. Likewise, the components of burnout were strongly correlated with the components of work engagement. We conducted t-test analyses to verify whether or not there were any discernible differences between public and private employees. The results showed that public employees tend to report higher levels of emotional exhaustion (M = 14.27; F = 0.799; p = 0.036) and perceived inequity (M = 3.65; F = 0.110; p = 0.023) than their private counterparts. As the results reported in Table 3 show, perceived inequity has a positive impact only on emotional exhaustion (β = 0.371; p = 0.000) and cynicism (β = 0.181; p = 0.011). Thus H1 was partially confirmed, while H2 was disproved. The regression analyses also showed that social support has a very strong effect on both burnout and engagement, in all their components. Specifically, it has a negative impact on emotional exhaustion (β = ; p = 0.024) and cynicism (β = ; p = 0.000), and a positive impact on personal accomplishment (β =0.250; p = 0.001), vigour (β = 0.204; p = 0.006), dedication (β = 0.242; p = 0.001) and absorption (β = 0.234; p = 0.002). Regarding the moderating hypotheses (H3 and H4), the interaction between perceived inequity and social support was found to have a positive impact on emotional exhaustion (β = 0.151; R 2 = 0.023; p = 0.021) and a negative impact on personal accomplishment (β = ; R 2 = 0.046; p = 0.002). In particular, in conditions of low perceived inequity, workers reporting lower levels of social support also reported higher levels of emotional exhaustion than workers with higher social support (Figure 1). As Figure 2 illustrates, in a situation of low perceived inequity, workers with perceived low social support report lower

11 Healthcare Professional Journal Vol.1, N. 1-4, Emotional Exhaustion Personal Accomplishment Low Perceived Inequity High Perceived Inequity 25 Low Perceived Inequity High Perceived Inequity Low Social Support High Social Support Low Social Support High Social Support Figure 1. Interaction effect between perceived inequity and social support on emotional exhaustion. Figura 1. Effetto interazione tra la percezione di iniquità e il supporto sociale sull esaurimento emotivo. Figure 2. Interaction effect between perceived inequity and social support on personal accomplishment. Figura 2. Effetto interazione tra la percezione di iniquità e il supporto sociale sul senso di riuscita professionale. levels of personal accomplishment than workers who perceived a high level of social support. We found no interaction effect between perceived inequity and social support as regards cynicism. Thus H3 was only partially confirmed. With regard to H4, the results show that an interaction between perceived inequity and social support affects all components of work engagement. As the figures show (Figure 3, 4 and 5), there is a strong interaction effect between perceived inequity and perceived social support, which affects all components of work engagement. In particular, in a situation of low perceived inequity, workers who perceived high social support report higher levels of vigour (β = ; R 2 = 0.068; p = 0.000), dedication (β = , R 2 = 0.06; p = 0.000) and absorption (β = ; R 2 = 0.057; p = 0.001). Finally, we found that whether an employee belongs to a private or public sector firm has an impact on both emotional exhaustion (β = 0.132; R 2 = 0.016; p < 0.05) and personal accomplishment (β = 0.195; R 2 = 0.036; p < 0.01). However, none of the three-way interactions were found to be statistically significant, so we can state that working in a private or in a public hospital does not have a buffer effect on the relationship between perceived inequity and burnout or engagement. DISCUSSION Our findings allow us to better understand the field of perceived inequity in healthcare settings. The results show that social support is a key variable to consider when we study of workplace conditions and analyse the effects of perceived inequity in the relationship between personal investment and rewards in organizations. As expected, our findings also confirmed that perceived inequity is related to job burnout, but it is not significantly related to job engagement. This strengthens Schaufeli et al. s (28) considerations about the engagement construct. Indeed, they state that engagement cannot be adequately measured by the opposite profile of MBI scores because it is a distinct construct, strongly related to burnout, but not detectable by the Maslach Burnout Inventory. This kind of finding suggests that changes in perceived inequity could have an effect only on emotional exhaustion and cynicism, i.e., negative personal outcomes. Indeed, we found that neither personal accomplishment nor engagement (all components) are affected by the perception of inequity, thereby appearing to confirm that inequity is a factor that only produces negative consequences, as many of the studies cited above suggest. Indeed the fact that a worker never reports,

12 Positive and negative effects of perceived inequity in Italian healthcare workers M. Vignoli 6 6 5,5 5,5 5 5 Vigor 4,5 4 Dedication 4,5 4 3,5 3,5 3 Low Perceived Inequity High Perceived Inequity 3 Low Perceived Inequity High Perceived Inequity Low Social Support High Social Support Low Social Support High Social Support Figure 3. Interaction effect between perceived inequity and social support on vigour. Figura 3. Effetto interazione tra la percezione di iniquità e il supporto sociale sul vigore. Figure 4. Interaction effect between perceived inequity and social support on dedication. Figura 4. Effetto interazione tra la percezione di iniquità e il supporto sociale sulla dedizione. for example, to invest in his/her work more than s/he receives in return is not a sufficient condition to produce engagement in his/her own work. Absorption Low Perceived Inequity High Perceived Inequity Low Social Support High Social Support Figure 5. Interaction effect between perceived inequity and social support on absorption. Figura 5. Effetto interazione tra la percezione di iniquità e il supporto sociale sull assorbimento. Looking at the moderation results, we detected an interactive effect of perceived inequity and perceived social support on emotional exhaustion and personal accomplishment. Specifically, in conditions of low perceived inequity (i.e. equity), workers who perceived high levels of social support reported lower levels of emotional exhaustion and higher levels of personal accomplishment. Indeed, as expected, perceived inequity and social support play an important role in determining the central variable of job burnout (emotional exhaustion) and personal accomplishment. Social support is strongly related to both perceived inequity and the outcomes investigated (burnout and engagement), and exerts a strong moderating effect on the relationship between perceived inequity and job engagement, reported here for the first time. Social support plays a crucial role in all three components of engagement (vigour, dedication and absorption). In fact, we found that in conditions of low perceived inequity, personnel with high perceived levels of social support also reported higher levels of job engagement. This suggests that in the healthcare setting we can enhance employee engagement by acting on perceived equity and improving social support. However, conversely, our findings indicate that when high levels of perceived inequity are reported, social support has no effect on outcomes such as job burnout and job en

13 Healthcare Professional Journal Vol.1, N. 1-4, 2012 gagement. This could be explained by the fact that although our scale of perceived inequity measures a holistic perception (the scale measures perceived equity with respect to colleagues and supervisors), if employees perceive higher levels of inequity at work, this could lead to their giving and, as a consequence, receiving less social support (and vice versa). This could be linked to and explained by the fact that social support also involves social exchange between workers. Our findings are also in line with important theoretical models, such as the Job Demand-control-support model (15) and the Job Demand-resources model (8). The first model mentioned states that high levels of demand combined with low control and low social support could produce adverse effects on health. Although we did not employ a variable for control over own work, we did find that social support moderates the relationship between perceived inequity and two dimensions of job burnout (emotional exhaustion and personal accomplishment). Our results also match the Job Demand-resources model, which states that job resources may buffer the effect of job demands on job strain. Indeed, as our findings show, social support moderates the relationship between perceived inequity and burnout. The Job Demand-resources model also suggests that the specific types of resources that buffer the impact of the kinds of job demands depend on the work environment. In our case, perceived inequity is an appropriate variable for the health-care context, due to the nature of the exchange of caregiving relations typical of such organizations. As regards the influence of the work sector (public or private), the expected differences were confirmed. First, in line with a recent study (7) conducted in Italy on a group of pulmonologists, emotional exhaustion is higher in public workers. Furthermore, perceived inequity is also higher for public workers than for private workers. CONCLUSIONS LIMITATIONS OF THE STUDY AND FUTURE RESEARCH Some limitations of this study have to be acknowledged. First of all, although perceptions of moderate inequity can be countered by a climate of social support, this is not the case when perceived inequity is high. In fact, the perceptions of moderate inequity can be contrasted by a social support climate. This means that social support, which is considered a general buffering variable for many negative outcomes in the workplace, may have some limitations when used to cope with high inequity. One limitation of our study was that our perceived inequity scale was unable to distinguish between inequity with respect to colleagues and inequity with respect to supervisors, and future research should carefully consider such a problem. Besides this, one should remember that equity is strictly linked to exchange: when the perceived equity decreases, people tend to give less social support (which can be considered a specific case for exchange) and likewise receive less social support, in a sort of self-maintained vicious circle. Moreover, our sample consisted of three different professional roles in the health-care context (practitioners, nurses and social workers), and though our results appear to be reasonably generalized to other job incumbents in healthcare, we do not know if workers in different jobs/positions would show differences in the relationship between perceived inequity and the outcomes studied. Furthermore, this research was conducted in a healthcare setting, and we are therefore not in a position to say whether the same relationship exists in other occupational fields centred around caregiving relationships (such as education), or those that do not feature this kind of exchange. This could be important, because if structuring practices that can influence the level of perceived reciprocity seems to be very difficult in healthcare workers due to the intrinsic nature of the professional field, managing equity in employees via social support interventions could result in enhanced work engagement in non-caregiving settings. Indeed, social support is an important variable in enhancing engagement, but more research is needed to ascertain whether there are other variables that can interact with perceived equity to influence work engagement. Finally, developing programmes aimed at modifying only negative aspects of work can improve employees general wellbeing, but would appear to be insufficient to enhance the involvement of workers in their own job. IMPLICATIONS FOR PRACTICE Our findings seem to support the implementation of HR services in the healthcare context. In fact, we are in a position to state that to enhance worker engagement, in both the public and private sectors, leaders

14 Positive and negative effects of perceived inequity in Italian healthcare workers M. Vignoli can act in two ways to improve this variable: by reducing perceived inequity and heightening social support from colleagues and supervisors. Although this could be easier for private supervisors, who can differentiate pay rewards and are generally less restricted in their actions than supervisors in the public sector, public managers can count on intrinsic levers, such as promoting a collaborative climate, encouraging workers and giving them autonomy at work and setting well-defined objectives, etc. to reduce perceived inequity and enhance perceived social support. REFERENCES 1. Adams JS. Inequity in social exchange (chapter 6). In: L Berkowitz (editor): Advances in experimental social psychology. Academic Press, New York (USA), 1965: ISBN Aiken LS, West SG. Multiple regression: Testing and interpreting interactions. Sage, Newbury Park (USA), ISBN Aryee S. Public and private sector professionals: A comparative study of their perceived work experience. Group Organ Manage 1992; 17 (1): Balducci C, Fraccaroli F, Schaufeli WB. Psychometric properties of the Italian version of the Utrecht Work Engagement Scale (UWES-9). A cross-cultural analysis. Eur J Psychol Assess 2010; 26 (2): Borgogni L, Galati D, Petitta L. Centro Formazione Schweitzer. Il questionario check up organizzativo. Manuale dell adattamento Italiano. Organizzazioni Speciali, Firenze, ISBN Cenni P, Barbieri F. Karasek s Job Content Questionnaire: Una versione italiana tradotta e adattata. [The Italian adaptation of the Karasek s Job Content Questionnaire.] Unpublished research report, Dal Negro RW, Sebastiano A. Il burnout in ambito medico pneumologico: evidenze empiriche da uno studio quantitativo su base nazionale. Sanità Pubblica e Privata 2010; 3: Demerouti E, Bakker AB, Nachreiner F, Schaufeli WB. The job demands-resources model of burnout. J Appl Psychol 2001; 86 (3): Festinger L. A theory of cognitive dissonance. Row & Peterson, Evaston (USA), ISBN González-Romá V, Schaufeli WB, Bakker AB, Lloret S. Burnout and work engagement: independent factors or opposite poles? J Vocat Behav 2006; 68 (1): Gottlieb BH. Theory into practice: issues that surface in planning interventions which mobilize support (chapter 12). In: IG Sarason, BR Sarason (editors): Social support: theory research and application. Martinus Nijhof, The Hague (NL), 1984: ISBN Guglielmi D, Paplomatas A, Simbula S, Depolo M. Prevenzione dello stress lavoro correlato: validazione di uno strumento per la valutazione dei rischi psicosociali nella scuola. Psicologia della Salute. 2011; 3: Hansung K. Job conditions, unmet expectations, and burnout in public child welfare workers: how different from other social workers? Child Youth Serv Rev. 2011; 33 (2): Karasek RA. Job content instrument: questionnaire and user s guide (version 1.1). University of Massachusetts, Lowell, Karasek RA, Theorell T. Healthy work: stress, productivity and the reconstruction of working life. Basic Books, New York (USA), ISBN Macklin DS, Smith LA, Dollard MF. Public and private sector work stress: workers compensation, levels of distress and job satisfaction, and the demand-control-support model. Aust J Psychol 2006; 58 (3): Maslach C, Jackson SE. Maslach Burnout Inventory Manual (research edition). Consulting Psychologists Press, Palo Alto (USA), ISBN Maslach C, Leiter MP. The truth about burnout: how organizations cause personal stress and what to do about it. Jossey-Bass, San Francisco (USA), ISBN Nahum-Shani I, Bamberger PA. Explaining the variable effect of social support on work-based stressor-strain relations: the role of perceived pattern of social exchange. Organ Behav Hum Decis Process 2011; 114 (1): Nunnally JC, Bernstein IH. Psychometric theory. Mc Graw-Hill, New York (USA), ISBN Perry LS. Effects of inequity on job satisfaction and selfevaluation in a national sample of African-American workers. J Soc Psychol 1993; 133 (4): Pierce GR, Sarason IG, Sarason BR. Coping and social support (chapter 10). In: M Zeidner, N Endler (editors): Handbook of coping: theory, research, applications. Wiley, New York (USA), 1996: ISBN Prins JT, Gazendam-Donofrio SM, Dillingh GS, Van de Wiel HBM, Van Der Heijden FMMA, Hoekstra-Weebers JEHM. The relationship between reciprocity and burnout in dutch medical residents. Med Educ 2008; 42 (7): Pritchard RD. Equity theory: a review and critique. Organ Behav Hum Perform 1969; 4 (2): Schaufeli WB, Bakker AB, Salanova M. The measurement of work engagement with a short questionnaire: a cross-national study. Educ Psychol Meas 2006; 66 (4): Schaufeli WB, Janczur B. Burnout among nurses: a Polish-Dutch comparison. J Cross Cult Psychol 1994; 25 (1):

15 Healthcare Professional Journal Vol.1, N. 1-4, Schaufeli WB, Leiter MP, Maslach C, Jackson SE. The MBI-General Survey. In: C Maslach, SE Jackson, MP Leiter (editors): Maslach Burnout Inventory Manual (3rd edition). Consulting Psychologists Press, Palo Alto (USA), 1996: ISBN Schaufeli WB, Salanova M, González-Romá V, Bakker AB. The measurement of engagement and burnout: a two sample confirmatory factor analytic approach. J Happiness Stud 2002; 3 (1): Sirigatti S, Stefanile C. The Maslach Burnout Inventory: adattamento e taratura per l Italia. Organizzazioni Speciali, Firenze, ISBN Smets EMA, Visser MRM, Oort FJ, Schaufeli WB, De Haes HJCJM. Perceived inequity: does it explain burnout among medical specialists? J Appl Soc Psychol 2004; 34 (9): Taris TW, Kalimo R, Schaufeli WB. Inequity at work: its measurement and association with worker health. Work Stress 2002; 16 (4): Terry DJ, Neilsen M, Perchard L. Effects of work stress on psychological well-being and job satisfaction: the stress buffering role of social support. Aust J Psychol 1993; 45 (3): Till R, Karren R. Organizational justice perceptions and pay level satisfaction. J Manag Psychol 2011; 26 (1), Truchot D. Le burn-out des médecins généralistes: influence de l iniquité perçue et de l orientation communautaire. Ann Med Psychol 2009; 167 (6): Truchot D, Deregard M. Perceived inequity, communal orientation and burnout: the role of helping models. Work Stress 2001; 15 (4): van Dierendonck D, Schaufeli WB, Buunk BP. Inequity among human service professionals: measurement and relation to burnout. Basic Appl Soc Psych 1996; 18 (4): van Dierendonck D, Schaufeli WB, Buunk BP. The evaluation of an individual burnout intervention program: the role of inequity and social support. J Appl Psychol 1998; 83 (3): van Dierendonck D, Schaufeli WB, Buunk BP. Burnout and inequity among service professionals: a longitudinal study. J Occup Health Psychol 2001; 6 (1): van Dierendonck D, Schaufeli WB, Sixma HJ. Burnout among general practitioners: a perspective from equity theory. J Soc Clin Psychol 1994; 13 (1): van Yperen NW, Hagedoorn M, Geurts SAE. Intent to leave and absenteeism as reactions to perceived inequity: The role of psychological and social constraints. J Occup Organ Psychol 1996; 69 (4): van Yperen NW, Buunk BP, Schaufeli WB. Communal orientation and the burnout syndrome among nurses. J Appl Soc Psychol 1992; 22 (3): DISCLOSURE. The Authors have no personal financial or institutional interest related to the subject matters discussed in this article

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17 Healthcare Professional Journal Vol.1, N. 1-4, 2012 Articolo originale Valutazione dell esposizione del tecnico sanitario di radiologia medica al campo magnetico statico in risonanza magnetica F. COELLI, D. RAVANELLI*, A. VALENTINI** Corso di Laurea in Tecniche di Radiologia Medica per Immagini e Radioterapia, Università degli Studi, Verona * Scuola di Specializzazione in Fisica Medica, Università degli Studi Tor Vergata, Roma ** Servizio di Fisica Sanitaria, Azienda Provinciale per i Servizi Sanitari, Trento RIASSUNTO: OBIETTIVO DELLO STUDIO. La risonanza magnetica è una tecnica di imaging che sfrutta l interazione di un intenso campo magnetico statico e di campi a radiofrequenze con il corpo umano per analizzarne le strutture interne, consentendo l acquisizione di immagini tridimensionali dotate di eccellente risoluzione spaziale e di contrasto. In risonanza magnetica l impiego di un elevato campo magnetico, di gradienti di campo e di radiofrequenze è associato alla presenza di un rischio sanitario, per il paziente, ma soprattutto per gli operatori sanitari. In particolare, il tecnico sanitario di radiologia medica è l operatore che, per motivi professionali, deve operare frequentemente in presenza dell azione continuativa del campo magnetico statico e di un ripido gradiente di campo. Il lavoro in oggetto si propone di effettuare una stima del rischio per i tecnici sanitari di radiologia medica che svolgono la loro attività in risonanza, confrontando i dati ottenuti con i limiti imposti dalla legge, e calcolando un rapporto di rischio per valutarne il rispetto. MATERIALI E METODI. Presso l Unità Operativa di Radiologia-Risonanza Magnetica dell Ospedale S. Chiara di Trento è stato attivato un periodo di ricerca che ci ha consentito di: 1) misurare con apposito cronometro i tempi di permanenza del tecnico in sala; i dati raccolti sono stati riordinati in apposite tabelle, suddivisi per tipologia d esame; 2) rilevare con un apposito dispositivo (rivelatore Talete-Tecnorad) l esposizione del tecnico sanitario di radiologia medica al campo magnetico statico e riordinare in appositi grafici (densità di flusso di campo-tempo) i valori misurati, rendendo possibile la creazione di una mappa delle esposizioni riportante le varie tipologie di esame e le varie fasi di lavoro. Sono stati utilizzati due rivelatori: uno posizionato alla fronte, ed uno al torace del tecnico sanitario di radiologia medica, al fine di confrontare eventuali differenze nei valori misurati. Le misure raccolte, opportunamente rielaborate, hanno consentito di stimare l entità del rischio per i tecnici sanitari di radiologia medica e di confrontare i risultati con i valori limite imposti dal D.Lgs 81/2008 (tabella allegato XXXVI) per le correnti indotte nel corpo dovute alle frequenze estremamente basse. RISULTATI. Le misure evidenziano un elevata variabilità dei valori dei tempi di permanenza per ogni singola tipologia d esame. Si eseguono in media 15 esami/die che espongono complessivamente il personale tecnico sanitario di radiologia medica per s/die, corrispondenti a 82,5 minuti/die. Da queste valutazioni risulta già che il tempo totale di permanenza in sala è inferiore ai limiti di legge per esposizione a più di 200 mt. Dalle stime effettuate, il tempo totale di esposizione ai campi magnetici superiori ai 200 mt, per tutti gli esami eseguiti nel periodo di indagine e cumulativo per tutti i tecnici sanitari di radiologia medica che lavorano presso la risonanza magnetica dell Ospedale S. Chiara, risulta di circa 28 ore/anno. Il limite massimo di legge è di 1 ora/giorno, che riferito ad un anno, tenuto conto che 5,5 giorni/settimana x 52 settimane/anno = 286 gior- Corrispondenza: Dr. Francesco Coelli, francesco.coelli@alice.it Healthcare Professional Journal 2012; 1 (1-4): ISSN: Articolo ricevuto in redazione in data 16 ottobre Copyright 2012 by new Magazine edizioni s.r.l., Trento, Italia, Tutti i diritti riservati

18 Valutazione dell esposizione del TSRM al campo magnetico statico in risonanza magnetica F. Coelli SIGLE: APSS = Azienda Provinciale per i Servizi Sanitari della Provincia di Trento; D.Lgs = Decreto Legislativo; D.M. = Decreto Ministeriale; D.P.R. = Decreto del Presidente della Repubblica; mdc = mezzo di contrasto; RM = Risonanza Magnetica; SAR = Specific Absorption Rate; TSRM = Tecnico Sanitario di Radiologia Medica; USB = Universal Serial Bus. ni/anno, diviene 286 ore/anno. Il rapporto di rischio è quindi stimabile in 28 (ore/anno) / 286 (ore/anno) = 0,097 ovvero circa il 10%. CONCLUSIONI. Il lavoro condotto presso la Risonanza Magnetica dell Ospedale S. Chiara di Trento, ha permesso di valutare attentamente l operato del tecnico sanitario di radiologia medica ed il rispetto delle norme di sicurezza. Dall analisi dei dati acquisiti, estrapolati all attività annuale, si evince che il rischio per gli operatori dovuto all esposizione al campo magnetico statico è basso, e sicuramente le intensità e i tempi rilevati di esposizione a campo magnetico statico degli operatori rientrano nei limiti prescritti dalla legge. Inoltre dal monitoraggio effettuato, seppur limitato, si è potuto ottenere una descrizione del carico di lavoro e di esposizione rappresentativa della realtà dell unità operativa di risonanza magnetica; tale descrizione non è mai stata effettuata se non con stime approssimative. PAROLE CHIAVE: Campo magnetico statico, Rischio di esposizione, Sicurezza in risonanza magnetica, Tempo di permanenza in sala magnete. Risk evaluation of MRI technician exposure to static magnetic fields SUMMARY: OBJECT. Magnetic resonance imaging (MRI) is an imaging technique that utilizes the interaction of an intense static magnetic field and radio frequency fields with the human body to analyse the internal structures of the latter. This technique consents the acquisition of three-dimensional images (3D) with excellent spatial resolution and contrast. However, the use of a high magnetic field, field gradients and radio frequencies in MRI is associated with a health risk for both the patient and healthcare workers, in particular the MRI technician. Indeed, being charged with operating the device, the MRI technician is exposed to a continuous static magnetic field and a steep gradient field on a daily basis. In order to protect such employees, there are legal limits to their exposure. This study was designed to determine the risk that MRI technicians are actually exposed to during the course of their routine professional activities and assess compliance with the nationally prescribed limits. MATERIALS AND METHODS. A research campaign was activated at the Radiology-MRI Unit of S. Chiara Hospital, Trento, Italy, in order to: measure the time the MRI team spends in the MRI room; detect the MRI team s exposure to the static magnetic field. The static magnetic field was measured with two continuous monitoring devices (Talete-Tecnorad detector), one positioned on the forehead of the duty technician and one on their chest, in order to compare any differences in measured values. Time data were reported in Tables, according to the type of examination performed, and measurements were plotted on a graph of magnetic field flux density over time. This consented the creation of a shot map showing the various types of examination and the various work phases. The measurements collected, appropriately revised, allowed us to estimate the magnitude of risk to the MRI technician and to compare these results with the limits imposed by Italian Legislative Decree 81/2008 (Annex Table XXXVI), the current law in force governing the use of induced extremely low frequency currents in the body. RESULTS. The time required for the MRI procedure, and therefore the time spent in the exposure risk area, was found to vary considerably between the different types of examination. Each technician performed an average of 15 tests per day, for a mean total time of 4,950 s/day, i.e., 82.5 min/day. This means that the team is on average exposed to below the maximum legal limit of 200 mt. Indeed, we estimated that the total time of exposure to magnetic fields above 200 mt, for all examinations conducted in survey period and cumulative for all MRI technicians working at S. Chiara Hospital MRI, is approximately 28 hours/years. The legal limit is 1 h/day, i.e., 286 hours/year. The ratio of risk was therefore estimated at 28 [hours/year] / 286 [hours/year] = 0.097, or approximately 10%. This study also gave us an opportunity to evaluate and describe the activity at the S. Chiara s MRI Unit, the first time such a detailed assessment has been performed. CONCLUSIONS. The research carried out at the S. Chiara Hospital MRI Unit, Trento, enabled us to carefully evaluate the work of its radiographers and confirm compliance with the safety standards in force. Extrapolation of the acquired data allowed us to estimate figures for annual activity, which suggest that the risk to the MRI technician caused by the exposure to the static magnetic field is low, and that the intensity and time exposure adheres to the prescribed limits. KEY WORDS: Static magnetic field, Exposure risk, Safety in magnetic resonance imaging, Time spent in technical room

19 Healthcare Professional Journal Vol.1, N. 1-4, 2012 INTRODUZIONE L impiego della RM è associato alla presenza di un rischio sanitario dovuto all elevato campo magnetico, ai gradienti di campo magnetico ed alle radiofrequenze, per il paziente ma anche per gli operatori che vengono sottoposti per periodi prolungati all azione del campo magnetico statico. I rischi all operatore dovuti all esposizione al campo magnetico sono dovuti a: l azione della forza magnetica su elettroliti in movimento; traslazione e torsione di protesi ferromagnetiche impiantate; attrazione di oggetti ferromagnetici nelle vicinanze del magnete; induzione di correnti elettriche in caso di gradienti di campo. Sebbene l esposizione a breve termine al campo magnetico, per le intensità di utilizzo clinico, sia stata considerata non dannosa per l organismo, l esposizione per lunghi periodi è ancora sotto osservazione scientifica (6). La legislazione italiana attuale (Tabella 1) stabilisce per gli operatori i limiti temporali di esposizione al campo magnetico statico, che sono fissati dal D.M. 2 agosto 1991 (Tabella 2) (4). Da questi limiti si può ricavare il tempo massimo di permanenza di un operatore ad una data intensità di campo magnetico (per le operazioni di posizionamento, centratura, ecc.). Nell aprile del 2004 Parlamento e Consiglio Europeo hanno adottato la direttiva 2004/40/EC relativa all esposizione occupazionale ai campi elettromagnetici (5). Tale documento, che gli stati membri dell Unione Europea dovevano recepire entro il 30 aprile 2008, è stato rinviato al Tuttavia alcuni Stati membri, fra cui anche l Italia, si sono già adeguati a tale norma. La Direttiva stabilisce i limiti per l esposizione dei lavoratori alle onde elettromagnetiche di frequenza comprese nel range GHz in termini di densità di corrente indotta nel tessuto corporeo e rateo di assorbimento specifico, considerando i rischi a breve termine per la salute e la sicurezza dei lavoratori e non tenendo conto invece dei possibili effetti a lungo termine, come carcinogenesi indotta dai campi elettromagnetici variabili nel tempo, della cui relazione non esiste ancora evidenza scientifica. Poiché i parametri a cui si fa riferimento sono di difficile misurazione, la Direttiva ha introdotto, oltre ai limiti di esposizione, dei valori di azione che altro non sono che la magnitudo di parametri direttamente Riferimento Normativo D.M. del 29 novembre 1985 art. 1 e 2 Sentenza Corte Costituzionale n. 216 dell 11 febbraio 1988 Validità attuale D.M. del 2 agosto 1991 art 7, allegati (1-6) Sentenza Corte Costituzionale, 17 marzo 1992 D.M. del 3 agosto 1993 D.P.R n. 542 dell 8 agosto 1994 art. 2, 4, 5, allegati A e B tutti gli articoli Tabella 1. Normativa italiana. Sono riportati i principali riferimenti normativi relativi all impiego della RM. Table 1. Italian legislation. Shows the principal regulatory references on the use of MRI. misurabili come campo elettrico indotto (E), campo magnetico indotto (H), flusso di campo magnetico indotto (B) e densità di potenza (S) (Tabella 3 e 4). Nota la costante giromagnetica di Larmor, che per gli atomi di idrogeno è pari a 42 MHz/T, si può facilmente ricavare il valore della frequenza di risonanza per il campo magnetico di 1,5 T, che è pari a 63 MHz (2). I limiti di SAR imposti per questo valore di frequenza sono rispettivamente: 0,4 W/kg nel corpo intero, 10 W/kg se localizzato a testa e tronco e 20 W/kg se localizzato alle estremità. L aderenza ai limiti di esposizione e ai valori di azione fornisce un elevato livello di protezione per quanto riguarda gli effetti sanitari risultanti dall interazione con i campi elettromagnetici presenti, ma tuttavia non consente di evitare i problemi di sicurezza dovuti all interazione di dispositivi medicali come pacemaker, defibrillatori, impianti cocleari, protesi ortopediche ferromagnetiche che costituiscono controindicazione assoluta per l accesso alla sala magnete. Parte esposta Intensità di campo Durata massima esposizione Corpo 200 mt 1 ora/giorno Corpo 2 T 15 min/giorno Arti 2 T 1 ora/giorno Arti 4 T 15 min/giorno Tabella 2. Valori temporali limite fissati dal D.M. 2 agosto Table 2. Time limits set by Italian Ministerial Decree 2 August

20 Valutazione dell esposizione del TSRM al campo magnetico statico in risonanza magnetica F. Coelli Intervallo delle frequenze Densità di corrente (J) per testa e tronco [ma/m 2 ] Tasso di assorbimento specifico (SAR) mediato su tutto il corpo [W/kg] Tasso di assorbimento specifico (SAR) localizzato a testa e tronco [W/kg] Tasso di assorbimento specifico (SAR) localizzato agli arti [W/kg] Densità di potenza (S) [W/m 2 ] Fino a 1 Hz Hz 40/f Hz Hz- 100 KHz f/ KHz- 10 MHz f/100 0, MHz-10GHz - 0, GHz Tabella 3. Limiti di esposizione (è evidenziato il range di interesse per la RM). Da Tabella 1 dell allegato XXXVI del D.Lgs. 81/2008. Table 3. Exposure limit values (the range of interest for the MRI is highlighted). From Table 1 Attachment XXXVI from Legislative Decree 81/2008. Il D.Lgs 81/2008 (3) pone dei valori limite (tabella 1 dell allegato XXXVI: campi elettromagnetici riportati in Tabella 3) per le correnti indotte nel corpo dovute a frequenze estremamente basse. Oltre al controllo sull osservanza delle norme di sicurezza che regolano le modalità operative all interno del sito è quindi Intervallo delle frequenze Intensità di campo elettrico (E) [V/m] Intensità di campo magnetico (H) [A/m] Densità di flusso magnetico (B) [µt] Densità di potenza di onda piana equivalente (Seq) [W/m 2 ] Corrente di contatto (IC) [ma] Corrente indotta attraverso gli arti (IL) [ma] 0-1 Hz - 1,63x10 5 2x10 5-1,0-1-8 Hz ,63x10 5 /f 2 2x105/f 2-1, Hz x10 4 2,5x10 4 /f - 1,0-0,025-0,82 khz 500/f 20/f 25/f - 1,0-0,82-2,5 khz ,4 30,7-1,0-2,5-65 khz ,4 30,7-0,4f khz /f 2000/f - 0,4f - 0,1-1 MHz 610 1,6/f 2/f MHz 610/f 1,6/f 2/f MHz 61 0,16 0, MHz 61 0,16 0, MHz 3f 1/2 0,008 f 1/2 0,01 f ½ f/ GHz 137 0,36 0, Tabella 4. Valori di Azione fissati dalla Direttiva Europea 2004/40/EC. È evidenziato il range di interesse per la RM da 1,5 T che utilizza campi statici (frequenza = 0) e radiofrequenze (frequenza = 65 khz). I valori di azione sono stati ottenuti dai limiti di esposizione sulla base della raccomandazioni ICNIRP 7/99 (International Non-Ionising Radiation Commitee). Da notare il limite 2 x 10 5 ut, che corrisponde a 200 mt, per la densità di flusso magnetico a 0 Hz ovvero per campi statici. Table 4. Action values set by European Directive 2004/40/EC. The range of interest for MRI using a 1.5 T static field (frequency = 0) and radio frequency of 65 khz is highlighted. The action values were obtained from the exposure limits recommended by the ICNIRP 7/99 (International Non-Ionizing Radiation Committee). Please note the limit 2 x 10 5 ut, which corresponds to 200 mt for the magnetic flux density at 0 Hz (static fields)