Tony Voet

Validation of MR-Based Polymer Gel Dosimetry as a Preclinical Three-Dimensional Verification Tool in Conformal Radiotherapy

The aim of this work was to investigate MR‐based polymer gel dosimetry as a three‐dimensional (3D) dosimetry technique in conformal radiotherapy. A cylindrical container filled with polymer gel was placed in a water‐filled torso phantom to verify a treatment plan for the conformal irradiation of a mediastinal tumor located near the esophagus. Magnetic resonance spin‐spin relaxation rate images were acquired and, after calibration, converted to absorbed dose distributions. The dose maps were compared with dose distributions measured using radiographic film. The average root‐mean‐square structural deviation, for the complete dose distribution, amounted to less than 3% between gel and film dose maps. It may be expected that MR gel dosimetry will become a valuable tool in the verification of 3D dose distributions. The influence of imaging artifacts arising from eddy currents, temperature drift during scanning, and B1 field inhomogeneity on the dose maps was taken into account and minimized. Magn Reson Med 43:116–125, 2000.

User Acceptance of a Picture Archiving and Communication System - Applying the Unified Theory of Acceptance and Use of Technology in a Radiological Setting

OBJECTIVE The aim of this study is to gain insight into the individual user acceptance of PACS by the radiology department staff of the Ghent University Hospital. Hereto a basic--direct effects only--form of UTAUT was assessed. METHODS Ninety-four questionnaires were distributed and 56 usable questionnaires were returned (19 radiologists - 37 technologists). The questionnaire consisted of scales of Venkatesh et al. [13] for performance expectancy (PE), effort expectancy (EE), facilitating conditions (FC), social influence (SI), self-efficacy (SE), attitude (ATT), anxiety (ANX) and behavioral intention (BI), and a scale of Moore et al. [22] to assess the perceived voluntariness of PACS-use. RESULTS The reliability of all scales, except FC and voluntariness, was acceptable to good. The voluntariness scale was divided into a mandatoriness (MAN) and a voluntariness (VOL) measure. Both radiologists and technologists seem to welcome PACS, with radiologists having higher ratings on PE, EE, ATT, VOL and BI. Only PE and FC were salient for predicting BI, while EE and SI were not salient. Variance explained in behavioral intention to use PACS was 48%. CONCLUSION Both radiologists and technologists were positive towards PACS and had strong intentions to use PACS. As other healthcare professionals, they appear to make their technology acceptance decision independent from their superiors, hereby focusing on usefulness rather than on ease of use. It is also important that support is supplied. Basic UTAUT is an adequate model to assess technology acceptance in a radiological setting.

fMRI of developmental stuttering: A pilot study

The purpose of this investigation was to explore the feasibility of fMRI in the study of developmental stuttering. Speech contrasts (loud versus silent reading) and language contrasts (reading of semantically meaningful text versus nonsense words) of six developmental stutterers and six nonstutterers were compared using a commercial 1 Tesla MR-Scanner (Siemens Expert). Results indicate that mapping cortical function in persons who stutter is indeed feasible, even with a 1TMR-system. Compared to normals the stutterers seemed to employ different and particularly less differentiated auditory and motor feedback strategies in speech. They apparently rely on auditory processing and on cerebellar contribution as much during silent reading as during reading aloud. Moreover, they showed a greater involvement of the right hemisphere in language processing, activating not only the typical language areas on the left but also and with equal magnitude the right side homologues of these areas. In spite of the promising results, at present several practical problems such as possible movement artifacts and possible masking through scanner noise still hamper a more straightforward use of fMRI in the study of developmental stuttering.

Optimizing Physicians’ Instruction of PACS Through E-Learning: Cognitive Load Theory Applied

This article outlines the strategy used by our hospital to maximize the knowledge transfer to referring physicians on using a picture archiving and communication system (PACS). We developed an e-learning platform underpinned by the cognitive load theory (CLT) so that in depth knowledge of PACS’ abilities becomes attainable regardless of the user’s prior experience with computers. The application of the techniques proposed by CLT optimizes the learning of the new actions necessary to obtain and manipulate radiological images. The application of cognitive load reducing techniques is explained with several examples. We discuss the need to safeguard the physicians’ main mental processes to keep the patient’s interests in focus. A holistic adoption of CLT techniques both in teaching and in configuration of information systems could be adopted to attain this goal. An overview of the advantages of this instruction method is given both on the individual and organizational level.

Framework for user acceptance: Clustering for fine-grained results

In an attempt to uncover intra-group behavior similarities, we developed an open multi-level framework for understanding the process of technology acceptance by its users. We partitioned our population into groups by clustering at several levels and then for each level it was divided into subgroups with a measurement layer added to uncover subgroup influence. Thus, by intersecting the resulting clusters of the set of models, the population was divided into subgroups that have similarities in the factors measured by the cluster layer models. Subsequently we tested our framework in a university hospital setting; personality and prior technology background models were used in clustering via the Five Factor Model and the Technology Readiness Index. UTAUT was used in the measurement layer. Our hypothesis that the subgroups have differing degrees of explained variance and different predictors was confirmed. Our framework was open, because any model that results in a taxonomy of the population can be used to obtain meaningful clusters.