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• Dose distribution was simulated by the developed approximate irregular field dose distribution program. • The program combined with a compensation bed to simulate the clinical application of radiotherapy. • The present findings indicate that it is possible to reach a gamma passing rate exceeded 70% under respiratory motion. This study optimized our previously proposed simulation program for the approximate irregular field dose distribution (SPAD) and applied it to a respiratory motion compensation system (RMCS) and respiratory motion simulation system (RMSS). The main purpose was to rapidly analyze the two-dimensional dose distribution and evaluate the compensation effect of the RMCS during radiotherapy. This study modified the SPAD to improve the rapid analysis of the dose distribution. In the experimental setup, four different respiratory signal patterns were input to the RMSS for actuation, and an ultrasound image tracking algorithm was used to capture the real-time respiratory displacement, which was input to the RMCS for actuation. A linear accelerator simultaneously irradiated the EBT3 film. The gamma passing rate was used to verify the dose similarity between the EBT3 film and the SPAD, and conformity index (CI) and compensation rate (CR) were used to quantify the compensation effect. The Gamma passing rates were 70.48–81.39% (2%/2mm) and 88.23–96.23% (5%/3mm) for various collimator opening patterns. However, the passing rates of the SPAD and EBT3 film ranged from 61.85% to 99.85% at each treatment time point. Under the four different respiratory signal patterns, CR ranged between 21% and 75%. After compensation, the CI for 85%, 90%, and 95% isodose constraints were 0.78, 0.57, and 0.12, respectively. This study has demonstrated that the dose change during each stage of the treatment process can be analyzed rapidly using the improved SPAD. After compensation, applying the RMCS can reduce the treatment errors caused by respiratory movements. [ABSTRACT FROM AUTHOR]

• We proposed a simulation program for simulating the approximate irregular field dose distribution. • RMSS (respiratory motion simulated system) was used to reproduce the respiration motion. • Diaphragm phantom displacement was extracted via UITA (ultrasound image tracking algorithm). • Static and dynamic dose distribution maps can be simulated based on the proposed matrix position parameters of various fields. • The present findings indicate that it is possible to develop a reusable and time-saving dose distribution measurement tool. This study used an ultrasound image tracking algorithm (UITA) in combination with a proposed simulation program for the approximate irregular field dose distribution (SPAD) to assess the feasibility of performing dose distribution simulations for two-dimensional radiotherapy. This study created five different types of multileaf collimator openings, and applied a SPAD to analyze the matrix position parameters for each regular field to generate a static program-simulation dose distribution map (PDDM), whose similarity was then compared with a static radiochromic film experimental-measurement dose distribution map (EDDM). A two-dimensional respiration motion simulation system (RMSS) was used to reproduce the respiration motion, and the UITA was used to capture the respiration signals. Respiration signals were input to the SPAD to generate two dynamic PDDMs, which were compared for similarity with the dynamic EDDM. In order to verify the dose distribution between different dose measurement techniques, the gamma passing rate with 2%/2 mm criterion was used for the EDDM and PDDM, the passing rates were between 94.31% and 99.71% in the static field analyses, and between 84.45% and 96.09% for simulations with the UITA signal input and between 89.35% and 97.78% for simulations with the original signal input in the dynamic field analyses. Static and dynamic dose distribution maps can be simulated based on the proposed matrix position parameters of various fields and by using the UITA to track respiration signals during radiation therapy. The present findings indicate that it is possible to develop a reusable and time-saving dose distribution measurement tool. [ABSTRACT FROM AUTHOR]

This study proposed respiratory motion compensation system (RMCS) combined with an ultrasound image tracking algorithm (UITA) to compensate for respiration-induced tumor motion during radiotherapy, and to address the problem of inaccurate radiation dose delivery caused by respiratory movement. This study used an ultrasound imaging system to monitor respiratory movements combined with the proposed UITA and RMCS for tracking and compensation of the respiratory motion. Respiratory motion compensation was performed using prerecorded human respiratory motion signals and also sinusoidal signals. A linear accelerator was used to deliver radiation doses to GAFchromic EBT3 dosimetry film, and the conformity index (CI), root-mean-square error, compensation rate (CR), and planning target volume (PTV) were used to evaluate the tracking and compensation performance of the proposed system. Human respiratory pattern signals were captured using the UITA and compensated by the RMCS, which yielded CR values of 34–78%. In addition, the maximum coronal area of the PTV ranged from 85.53 mm 2 to 351.11 mm 2 (uncompensated), which reduced to from 17.72 mm 2 to 66.17 mm 2 after compensation, with an area reduction ratio of up to 90%. In real-time monitoring of the respiration compensation state, the CI values for 85% and 90% isodose areas increased to 0.7 and 0.68, respectively. The proposed UITA and RMCS can reduce the movement of the tracked target relative to the LINAC in radiation therapy, thereby reducing the required size of the PTV margin and increasing the effect of the radiation dose received by the treatment target. [ABSTRACT FROM AUTHOR]

Objectives We aimed to identify disability trajectories and examine whether the predisposing, intra-individual, and extra-individual factors in the disablement process predicted different disability trajectories among older adults in Taiwan. Methods Data were from the Taiwan Longitudinal Study on Aging (TLSA) Survey in 1996–2007 ( n = 3186). Disability trajectories for activities of daily living (ADLs) and instrumental activities of daily living (IADLs) were identified by using latent class growth curves modeling. Factors including demographics, health conditions, health behaviors, social relations, and use of assistive devices were significantly predicted different disability trajectories of older adults over the following 11 years by applying hierarchical logistic regression. Results Three disability trajectories – maintained function, progressive disability, and consistent disability – were identified. Predisposing factors such as younger age, more educational attainment, and better health conditions had protective effects of leading to a later healthier maintained function trajectory. Intra-individual factors such as engaging in leisure time activities (LTAs) were positively related to the maintained function trajectory but negatively related to the consistent disability trajectory; decreasing social networks was common to those on consistent disability trajectory; dissatisfaction with social support was noted in maintained function trajectory group. An extra-individual factor, using assistive devices, was significantly related to maintaining older adults’ disability levels, even for those who started disabled. Conclusions The findings suggested that predisposing, intra-individual, and extra-individual factors play different roles in the development of later disability trajectories. More educational attainment, better health conditions, active in LTAs, and using assistive devices might benefit the maintenance of functioning in Taiwanese older adults. [ABSTRACT FROM AUTHOR]

• We applied the wavelet transform to a two-dimensional respiratory motion compensation system. • The results indicated that the compensation effect for various respiratory signals had been improved. • The results showed that the compensation rate had improved from 67.96 to 88.05%. This study evaluated the feasibility of applying the wavelet transform (WT) combined with a phase-lead compensator (PLC) to our previously developed two-dimensional respiratory motion compensation system (RMCS). This system automatically and instantaneously adjusts PLC parameters according to different respiration signals to reduce influences of the system delay time, improving the compensation effect of the RMCS during respiratory motion compensation. This study performed respiratory movement compensation experiments with a two-dimensional respiratory motion simulation system (RMSS) and the RMCS. Human respiratory signals were captured using our previously developed ultrasound image tracking algorithm (UITA). In this study, a displacement compensation RMCS algorithm based on the combination of WT and PLC was developed by LabVIEW, which allows an automatic adjustment of the PLC parameters according to various respiratory waveforms, achieving a better compensation effect. The experiment results indicated that the compensation rate (CR) of right-left and superior-inferior directions had both improved 67.96–88.05% and 70.38–91.43%, respectively. In this study, the proposed method combined with WT and PLC applied in respiratory movement compensation experiments; the UITA was used for tracking diaphragm motion which substitutes for tumor motion. This noninvasive monitoring method also helps reduce side effects after treatment. The experimental results indicated that the effect of using the WT combined with the PLC to compensate for various respiratory signals was improved over our previously developed compensation algorithm. [ABSTRACT FROM AUTHOR]

This study had two aims: (a) to identify the different patterns of use of home- and community-based services (HCBS) among older adults in Taiwan, and (b) to examine the effects of the different use patterns on HCBS recipients' use of institutional long-term care services. The study analyzed cohort data from Taiwan's first National 10-Year Long-Term Care Plan database and from National Health Insurance Claim Data. We extracted baseline information on older adults who were first evaluated for and prescribed HCBS from 2010 through 2013 (N = 71,260). We used latent class analysis to specify the underlying subgroups of recipients with similar patterns of HCBS use. We used hierarchical multinomial logistic regression to examine the effect of the different use patterns on the risk of institutional (e.g., nursing home) placement from 4 to 15 months after initial HCBS evaluation. Four subgroups of HCBS recipients were identified, with patterns of home-based personal care (PC), home-based personal care and medical care (PC/MC), home-based medical care (MC), and community care services. Compared to the home-based PC/MC group, people in the home-based MC group had lower risk (OR = 0.54) and people in the community care group had higher risk (OR = 1.76) of admission to a nursing home. Study findings may provide insights for policy makers regarding the usefulness of integrating medical care and other types of long-term care services into adult day care. • Four subgroups of HCBS service patterns were identified. • The home-based medical care use pattern appears to support aging in place. • Integrate medical care and other long-term care services into community-based care. [ABSTRACT FROM AUTHOR]