Quantification of proton dose calculation accuracy in the lung

PURPOSE

To quantify the accuracy of a clinical proton treatment planning system (TPS) as well as Monte Carlo (MC)-based dose calculation through measurements and to assess the clinical impact in a cohort of patients with tumors located in the lung.

METHODS AND MATERIALS

A lung phantom and ion chamber array were used to measure the dose to a plane through a tumor embedded in the lung, and to determine the distal fall-off of the proton beam. Results were compared with TPS and MC calculations. Dose distributions in 19 patients (54 fields total) were simulated using MC and compared to the TPS algorithm.

RESULTS

MC increased dose calculation accuracy in lung tissue compared with the TPS and reproduced dose measurements in the target to within ±2%. The average difference between measured and predicted dose in a plane through the center of the target was 5.6% for the TPS and 1.6% for MC. MC recalculations in patients showed a mean dose to the clinical target volume on average 3.4% lower than the TPS, exceeding 5% for small fields. For large tumors, MC also predicted consistently higher V5 and V10 to the normal lung, because of a wider lateral penumbra, which was also observed experimentally. Critical structures located distal to the target could show large deviations, although this effect was highly patient specific. Range measurements showed that MC can reduce range uncertainty by a factor of ~2: the average (maximum) difference to the measured range was 3.9 mm (7.5 mm) for MC and 7 mm (17 mm) for the TPS in lung tissue.

CONCLUSION

Integration of Monte Carlo dose calculation techniques into the clinic would improve treatment quality in proton therapy for lung cancer by avoiding systematic overestimation of target dose and underestimation of dose to normal lung. In addition, the ability to confidently reduce range margins would benefit all patients by potentially lowering toxicity.

Reliability and utility of the Behaviour Support Plan Quality Evaluation tool (BSP-QEII) for auditing and quality development in services for adults with intellectual disability and challenging behaviour

BACKGROUND

Having an objective means of evaluating the quality of behaviour support plans (BSPs) could assist service providers and statutory authorities to monitor and improve the quality of support provided to people with intellectual disability (ID) who exhibit challenging behaviour. The Behaviour Support Plan Quality Evaluation Guide II (BSP-QEII) was developed to monitor and assess BSPs prepared by teachers to support children with disability in the school system. This study investigated the application of the BSP-QEII to the assessment of BSPs for adults with ID in community support services.

METHOD

The inter-rater reliability of the BSP-QEII was assessed. The utility of the BPS-QEII was then investigated with reference to a time series study of matched pairs of BSPs, developed for the same clients over a period of approximately 3 years. Differences in plan quality measured across a number of service and systemic variables were also investigated.

RESULTS

The BSP-QEII was found to have good inter-rater reliability and good utility for audit purposes. It was able to discriminate changes in plan quality over time. Differences in plan quality were also evident across different service types, where specialist staff had or had not been involved, and in some instances where a statutory format for the plan had or had not been used. There were no differences between plans developed by government and community sector agencies, nor were there any regional differences across the jurisdiction.

CONCLUSIONS

The BSP-QEII could usefully be adopted as an audit tool for measuring the quality of BSPs for adults with ID. In addition to being used for research and administrative auditing, the principles underpinning the BSP-QEII could also be useful to guide policy and educational activities for staff in community based services for adults with ID.

The content validity of the Behaviour Support Plan Quality Evaluation tool (BSP-QEII) and its potential application in accommodation and day-support services for adults with intellectual disability

BACKGROUND

The quality of support provided to people with disability who show challenging behaviour could be influenced by the quality of the behaviour support plans (BSPs) on which staff rely for direction. This study investigated the content validity of the Behaviour Support Plan Quality Evaluation tool (BSP-QEII), originally developed to guide the development of BSPs for children in school settings, and evaluated its application for use in accommodation and day-support services for adults with intellectual disability.

METHOD

A three-round Delphi study involving a purposive sample of experienced behaviour support practitioners (n = 30) was conducted over an 8-week period. The analyses included deductive content analysis and descriptive statistics.

RESULTS

The 12 quality domains of the BSP-QEII were affirmed as valid for application in adult accommodation and day-support service settings. Two additional quality domains were suggested, relating to the provision of detailed background on the client and the need for plans to reflect contemporary service philosophy. Furthermore, the results suggest that some issues previously identified in the literature as being important for inclusion in BSPs might not currently be a priority for practitioners. These included: the importance of specifying replacement or alternative behaviours to be taught, descriptions of teaching strategies to be used, reinforcers, and the specification of objective goals against which to evaluate the success of the intervention programme.

CONCLUSIONS

The BSP-QEII provides a potentially useful framework to guide and evaluate the development of BSPs in services for adults with intellectual disability. Further research is warranted to investigate why practitioners are potentially giving greater attention to some areas of intervention practice than others, even where research has demonstrated these others areas of practice could be important to achieving quality outcomes.

Use of antibiotic prophylaxis in elective inguinal hernia repair in adults in London and south-east England: a cross-sectional survey

Purpose

Evidence regarding whether or not antibiotic prophylaxis is beneficial in preventing post-operative surgical site infection in adult inguinal hernia repair is conflicting. A recent Cochrane review based on 17 randomised trials did not reach a conclusion on this subject. This study aimed to describe the current practice and determine whether clinical equipoise is prevalent.

Methods

Surgeons in training were recruited to administer the Survey of Hernia Antibiotic Prophylaxis usE survey to consultant-level general surgeons in London and the south-east of England on their practices and beliefs regarding antibiotic prophylaxis in adult elective inguinal hernia repair. Local prophylaxis guidelines for the participating hospital sites were also determined.

Results

The study was conducted at 34 different sites and received completed surveys from 229 out of a possible 245 surgeons, a 93 % response rate. Overall, a large majority of hospital guidelines (22/28) and surgeons’ personal beliefs (192/229, 84 %) supported the use of single-dose pre-operative intravenous antibiotic prophylaxis in inguinal hernia repair, although there was considerable variation in the regimens in use. The most widely used regimen was intravenous co-amoxiclav (1.2 g). Less than half of surgeons were adherent to their own hospital antibiotic guidelines for this procedure, although many incorrectly believed that they were following these.

Conclusion

In the south-east of England, there is a strong majority of surgical opinion in favour of the use of antibiotic prophylaxis in this procedure. It is therefore likely to be extremely difficult to conduct further randomised studies in the UK to support or refute the effectiveness of prophylaxis in this commonly performed procedure.