Purpose: Radiology departments are making the transition from analog film to digital images by means of PACS (Picture Archiving and Communication System). It is critical for the hospital that its physicians adopt and accept the new digital work method regarding radiological information. The aim of this study is to investigate hospital physicians' acceptance of PACS using questionnaires pre- and post-implementation and to identify main influencing factors. Materials and Methods: The study was conducted in an 1169 bed university hospital. The UTAUT (Unified Theory of Acceptance and Use of Technology) questionnaire [1] was administered at two times: one month pre-implementation (T1) and 1.5 years post-implementation (T2) of PACS, targeting all hospital physicians with the exemption of radiologists. The UTAUT scales (Behavioral Intention BI; Facilitating Conditions FC; Effort Expectancy EE; Performance Expectancy PE; Anxiety ANX; Social Influence SI; System Use USE; Attitude toward technology ATT; Self-Efficacy SE) were used to assess questions regarding: a) PACS' usefulness, b) PACS' ease of learning/using, c) PACS support availability, d) the perceived pressure to use PACS, e) physicians' attitude towards PACS and f) physicians' intention to use and actual use of PACS. Results: At T I scale ratings were positive toward the PACS implementation. The ratings on all scales with the exception of self-efficacy improved at T2. Regression analysis revealed that the key factor for intention to use PACS at T1 was the usefulness of PACS, while the availability and awareness of support was its most important predictor at T2. Overall, PE was the best predictor of BI, but all four UTAUT-determinants (PE, FC, EE and SI) were salient for its prediction. Variance explained in BI ranged from 31 to 37 % while variance explained in USE was very low (3 %). Conclusion: The implementation of PACS has succeeded. At T1 the physicians were welcoming PACS and this was confirmed at T2. Experience with PACS led to an overall improved attitude toward PACS. The key factors for physicians' intentions to use PACS were the usefulness of PACS (at T1 and overall) and the availability of support (at T2).
