Physician's expectations regarding prescribing clinical decision support systems in a Belgian hospital.

OBJECTIVES: Developing and implementing clinical decision support systems (CDSSs) is time-consuming and costly. Therefore, prioritization of the most relevant systems is warranted. The physician's perceived usefulness has been identified as a decisive reason for using CDSSs. The objective of this study was to investigate the physician's perceived usefulness of different types of CDSSs and to identify the user needs and expectations regarding future CDSSs. METHODS: Cross-sectional single-centre survey among physicians with a clinical assignment in a university hospital. Physicians were questioned about their current experiences with drug prescribing and the perceived usefulness and desired features of future CDSSs. RESULTS: One hundred and sixty-four physicians completed the survey (52·6%). The majority acknowledged that it is very difficult to take all relevant information into account when prescribing drugs. Drug-drug interaction checking, drug-allergy checking, and dosing guidance were considered as most useful. Automated clinical guidelines and adverse drug event monitoring were considered as least useful. The user-friendliness of the systems, clinical relevance of the alerts, and prevention of alert fatigue were perceived as important aspects for a successful implementation. CONCLUSIONS: From the physicians' perspective drug-drug interaction checking, drug-allergy checking, and dosing guidance should receive the highest priority for development and implementation. Because the perceived usefulness has been identified as a decisive reason for using CDSSs, it seems feasible to take into account this prioritization when developing and implementing CDSSs. In order to overcome the physicians' perceived disadvantages, attention should go to the development of user-friendly systems that deliver clinical relevant alerts.

The effect of timing of the provision of information on anxiety and satisfaction of cancer patients receiving radiotherapy.

BACKGROUND: To improve the provision of information to their radiotherapy patients, the authors examined whether the timing of given written information has an effect on anxiety and satisfaction. METHODS: Two sources of information were used: 1) a booklet with a description of radiotherapy procedures and the sensations patients can experience; 2) teaching sheets with treatment-site-related information. 68 patients were randomized to a simultaneous-information group (n = 31) and a stepwise-information group (n = 37). The patients were being treated for cancers of the breast, lung, head, and neck or the pelvic region. The authors analyzed the impacts of several variables on patient learning, including anxiety, age, gender, support, referral, stage of illness, and diagnosis. Assessments were recorded before the simulation procedure and during the second and last weeks of treatment. RESULTS: The stepwise-information group was significantly less anxious before simulation (p = 0.02) and more satisfied (p = 0.001). Of the variables studied, only the support variable was associated with high state anxiety (p < 0.0001). CONCLUSIONS: Provision of patient information in a stepwise format leads to less treatment-related anxiety and greater patient satisfaction among radiation therapy patient undergoing simulation.

Microprocessor controlled limitation system for a stand-alone freely movable treatment couch.

Because of the capability of free movement in the treatment room, we recently introduced a Hercules treatment couch on one of our linear accelerators. One of the advantages of this couch is that it allows for a more flexible way of patient setup and that it can be moved entirely out of the way to enable treatment with a hospital bed. A disadvantage, however, is that the couch can hit a wall or a cover of the accelerator accidentally. A limitation system has been developed to protect both the table and the accelerator against such collisions.

Electronic portal imaging with on-line correction of setup error in thoracic irradiation: clinical evaluation.

PURPOSE: To analyze setup errors and the feasibility of their on-line correction using electronic portal imaging in the irradiation of lung tumors. METHODS AND MATERIALS: Sixteen patients with lung cancer were irradiated through opposed anteroposterior fields. Localization images of anteroposterior fields were recorded with an electronic portal imaging device (EPID). Using an in-house developed algorithm for on-line comparison of portal images setup errors were measured and a correction of table position was performed with a remote couch control prior to treatment. In addition, residual errors were measured on the EPID verification image. Global and individual mean and standard deviation of setup errors were calculated and compared. The feasibility of the procedure was assessed measuring intra- and interobserver variability, influence of organ movement, reproducibility of error measurement, the extra time fraction needed for measuring and adjusting and the fraction of dose needed for imaging. RESULTS: In two setups the procedure could not be finished normally due to problems inherent to the procedure. The reproducibility, intraobserver variability, and influence of organ movements were each described by a distribution with a mean value less than or equal to 1 mm and a standard deviation (SD) of less than 1.5 mm. The interobserver variability showed to be a little bit larger (mean: 0.3 mm, SD: 1.7 mm). The mean time to perform the irradiation of the anteroposterior field was 4 +/- 1 min. The mean time for the measurement and correction procedure approximated 2.5 min. The mean extra time fraction was 65 +/- 24% (1 SD) with more than half of this coming from the error measurement. The dose needed for generation of EPID images was 5.9 +/- 1.4% of total treatment dose. The mean and SD of setup errors were, respectively, 0.1 and 4.5 mm for longitudinal and -2.0 and 5.7 mm for transversal errors. Of 196 measured translational errors 120 (61%) exceeded the adjustment criteria. For individual patients systematic and random setup errors can be as high as, respectively, 15.8 and 7.5 mm. Mean residual error and SD were for longitudinal direction 0.08 and 1.2 mm and for transversal direction -0.9 and 1.0 mm (pooled data). For individuals, the mean residual errors were smaller than 1 mm, with a typical SD per patient of less than 2 mm. CONCLUSION: Setup errors in thoracic radiation therapy are clinically important. On-line correction can be performed accurately with an objective measurement tool, although this prolongs the irradiation procedure for one field with 65%.

Dynamic radiotherapy: interactive movement of patient couch for treatment of craniospinal axis.

PURPOSE: The various techniques that have been described for treatment of the craniospinal axis show the common challenge of edge matching between adjacent orthogonal and parallel photon beams. Such edge matching is needed because the maximum field length provided by modern treatment machines is generally insufficient to treat adults with less than three matching fields. Using the common techniques, field edge matching becomes difficult, if for medical reasons, the patient cannot be treated in the prone position. METHODS AND MATERIALS: A scanning couch technique is proposed, with the patient lying in supine position. After treating the cerebral and upper neck regions by two lateral opposed half beam fields defined by asymmetric collimators (split beam), the patient is being moved along the spinal axis through an 8.0 cm wide by 15.0 cm long posterior split beam (allowing edge matching with the lateral fields at the neck region) by means of remote controlled couch movement. Stopping and starting of the scanning field resulted in a linear decrease of dose on both sides of the scan. Two ways of resolving this problem were investigated. RESULTS: The administered dose varied less than 8.5% through the craniospinal axis. Flatness of the rectangular scanned field was 0.76%. Apart from dose homogeneity, patient comfort and decreased simulation time are major advantages. CONCLUSIONS: The proposed technique represents a suitable alternative using a common linear accelerator, requiring a remote couch controller as an additional component.

Interactive use of on-line portal imaging in pelvic radiation.

We have evaluated a fluoroscopic on-line portal imaging system in routine clinical radiotherapy, involving the treatment of 566 pelvic fields on 13 patients. The image was typically generated by delivering a radiation dose of 6-8 cGy. Comparison between portal image and simulator film was done by eye and all visible errors were corrected before continuing irradiation. If possible, these corrections were performed from outside the treatment room by moving the patient couch by remote control or by changing collimator parameters. Adjustments were performed on 289/530 (54.5%) evaluable fields or 229/278 (82.4%) evaluable patient set-ups. The lateral couch position was most frequently adjusted (n = 254). The absolute values of the adjustments were 6.8 mm mean (SD 6.6 mm) with a maximum of 40 mm. All absolute values of adjustments exceeding 25 mm were recorded in one patient and those exceeding 15 mm were observed in two patients. Both patients were obese females. Adjustments exceeding 5 mm were observed in all 13 patients. Related to the use of on-line portal imaging, treatment time was increased by a median of 36.5% (mean 45.8%; SD 42.1%). The range was 7.7 to 442%. The fraction of the total treatment time to perform corrections was 22.7% median (mean: 26.0; SD: 11.8%). Statistically significant systematic in-plane errors were found in 7/13 patients. A systematic error was detected on the lateral position of the field in five patients. In one patient a systematic error of the longitudinal field position and in one patient a rotational error was detected. For adjustments in the lateral direction the present method does not allow to detect lateral shifts of less than 2 mm. For adjustments in the longitudinal direction the sensitivity could not be estimated but the available data suggest that 80% of errors < or = 5 mm were not adjusted. In obese patients, random errors may be surprisingly large.

Routine clinical on-line portal imaging followed by immediate field adjustment using a tele-controlled patient couch.

We have evaluated the fluoroscopic on-line portal imaging (OPI) system developed by Siemens (Beamview-1, Concord, CA, U.S.A.) in routine clinical radiotherapy, involving the treatment of 883 fields (559 patient set-ups for treatment) on 21 patients. The image was typically generated by delivering 10 monitor units when used in single exposure or 1-2 monitor units on a large open field followed by 8-10 monitor units on the actual field when double exposure was used. Comparison between the portal image and the simulator film was done by eye. A region of tolerance was drawn on the simulator film and the field edges on the portal image had to project within this region. If this criterion was not met, adjustments followed by verification portal images were done before the remaining field dose was delivered. If possible, these adjustments were performed by moving the patient couch by remote control. The image quality was insufficient for evaluation in 75/883 (8.5%) fields. The abovementioned criterion was not met in 95/808 (11.8%) of the evaluable fields (26/559 patient set-ups were not evaluable). Of the 533 evaluable patient set-ups, 92 had to be adjusted (17.2%) including three (pelvic irradiations) set-ups that were adjusted on both field irradiated during the same radiotherapy session. In one case an incorrect tray (with wrong blocks) was detected and replaced. In one case (a 5.5 x 6.0 cm rectangular larynx field) the x and y axis of the field were interswitched. In one case incorrect focusing of a block was shown by the portal image. To make adjustments, the couch longitudinal position was changed 20 times (range -10 to +15 mm). The lateral position was changed 73 times (range -15 to +16 mm). The height position was changes 6 times (range -7 to +6 mm). Diaphragma rotation changes were performed 5 times (1 degree). The fraction of treatment time that was related to the use of OPI was 30.7% median (mean 32.4%, S.D. 14.1%). The range was 4.1 to 78.6%. On the basis of calculations assuming no OPI would have been used, field treatment time was increased by a median of 44.2% (mean 55.8%; S.D. 41.2%) by using OPI. The fraction of monitor units (fraction of the dose) to generate a satisfactory image was 10% median.(ABSTRACT TRUNCATED AT 400 WORDS)