A design of a DICOM-RT-based tool box for nonrigid 4D dose calculation.

The study was aimed to introduce a design of a DICOM-RT-based tool box to facilitate 4D dose calculation based on deformable voxel-dose registration. The computational structure and the calculation algorithm of the tool box were explicitly discussed in the study. The tool box was written in MATLAB in conjunction with CERR. It consists of five main functions which allow a) importation of DICOM-RT-based 3D dose plan, b) deformable image registration, c) tracking voxel doses along breathing cycle, d) presentation of temporal dose distribution at different time phase, and e) derivation of 4D dose. The efficacy of using the tool box for clinical application had been verified with nine clinical cases on retrospective-study basis. The logistic and the robustness of the tool box were tested with 27 applications and the results were shown successful with no computational errors encountered. In the study, the accumulated dose coverage as a function of planning CT taken at end-inhale, end-exhale, and mean tumor position were assessed. The results indicated that the majority of the cases (67%) achieved maximum target coverage, while the planning CT was taken at the temporal mean tumor position and 56% at the end-exhale position. The comparable results to the literature imply that the studied tool box can be reliable for 4D dose calculation. The authors suggest that, with proper application, 4D dose calculation using deformable registration can provide better dose evaluation for treatment with moving target.

A separated primary and scatter model for independent dose calculation of intensity modulated radiotherapy.

BACKGROUND AND PURPOSE: Independent checking of beam monitor units is an essential step in the preparation of any radiotherapy plan. The present work describes a simple model for calculating a point dose from an arbitrary number of irregular, asymmetric fields, typical of beam segments used for IMRT. MATERIALS AND METHODS: Primary and scatter dose contributions were separated using a two-parameter exponential fit to measured beam data, from which differential scatter is determined. A total of 60 IMRT patient plans for a five-field prostate class solution were investigated to validate the model. RESULTS: The average difference between the model's prediction and direct measurement of reference dose was found to be -0.6% (ranging from -2.9% to +1.6%), with a standard deviation of 1.0%. This compares well with the observed average difference between treatment planning system prediction and direct measurement of +0.8% (SD 0.6%). CONCLUSIONS: The model is shown to provide a reliable and accurate independent check of planning system monitor units for the prostate IMRT plans studied. Implementation of the model could significantly reduce the time needed for point dose verification of IMRT plans currently performed by direct measurement.

Communicative sensitivity in the bilingual healthcare setting: a qualitative study of language awareness.

AIM: This paper reports on the second phase of a national study in Wales. The research aimed to assess the level of Welsh language awareness amongst healthcare professionals across Wales, and to identify the factors that enhance language choice within service delivery. BACKGROUND: The literature suggests that language sensitive healthcare practice is central to ensuring high quality care. However, it is evident that language barriers continue to compromise the quality of care within nursing and other health services. One issue that has received little attention is the level of language awareness that healthcare professionals currently demonstrate. Furthermore the factors that influence language choice for bilingual/multilingual speakers are not well explored in the literature. METHODS: The study involved semi-structured interviews with a range of healthcare professionals in acute and community settings across Wales. Using a systematic sampling matrix, a purposeful sample of 83 professionals was selected to participate. Twenty-seven of the respondents were nurses, health visitors and midwives. The interviews focussed on the factors that facilitate or impede language sensitive healthcare practice. All interviews were audiotaped and, using a framework analysis approach, conceptual codes were developed and defined and categories and sub-categories were constructed to create thematic charts. FINDINGS: Three main themes were identified: care enhancement, which focussed on the process and outcome of offering language choice to bilingual patients; organizational issues, which reflected issues relating to the infrastructure of service provision; and training implications, which focused on Welsh language learning in health care. CONCLUSIONS: Complex dynamics of language use are in operation within bilingual healthcare settings and organizational as well as individual factors are important in facilitating appropriate language use. Many of the issues highlighted are not peculiar to the Welsh context, but apply to healthcare settings across the world, where other minority languages are in use.