Ikspite a rapid iricre'rse in disabled cldcrly in Jcip.in, the burden of the c~regivci-h'is u o t hccn properly lack of objective ~iie~r~tireiiiciits. Our stiidy w a s 'iiiiied at ad

Purpose To evaluate the accuracy and consistency of a gradient-based PET segmentation method, GRADIENT, as compared to manual (MANUAL) and constant threshold (THRESHOLD) methods. Methods and Materials Contouring accuracy was evaluated with sphere phantoms and clinically realistic Monte Carlo PET phantoms of the thorax. The sphere phantoms were 10–37 mm in diameter and were acquired at 5 institutions emulating clinical conditions. One institution also acquired a sphere phantom with multiple source-to-background ratios (SBR) of 2:1, 5:1, 10:1, 20:1, and 70:1. One observer segmented (contoured) each sphere with GRADIENT and THRESHOLD from 25–50% at 5% increments. Subsequently, seven physicians segmented lessions (7–264ml) from 25 digital thorax phantoms using GRADIENT, THRESHOLD, and MANUAL. Results For spheres < 20 mm in diameter, GRADIENT was the most accurate with a mean absolute %error in diameter of 8.15% (10.2%SD) compared to 49.2% (51.1%SD) for 45% THRESHOLD (p < 0.005). For larger spheres the methods were statistically equivalent. For varying SBR, GRADIENT was the most accurate for spheres > 20 mm, (p < 0.065) and < 20 mm (p < 0.015). For digital thorax phantoms, GRADIENT was the most accurate, (p-value < 0.01), with a mean absolute %error in volume of 10.99% (11.9%SD) followed by 25% THRESHOLD at 17.5% (29.4%SD), and MANUAL, at 19.5% (17.2%SD). GRADIENT had the least systematic bias, 4 with a mean %error in volume of −0.05% (16.2%SD) compared with 25% THRESHOLD at - 2.1% (34.2%SD) and MANUAL at −16.3% (20.2%SD) (p-value < 0.01). Inter-observer variability was reduced using GRADIENT compared to both 25% THRESHOLD and MANUAL (p-value < 0.01, Levene's Test). Conclusion GRADIENT was the most accurate and consistent technique for target volume contouring. GRADIENT was also the most robust for varying imaging conditions. GRADIENT has the potential to play an important role for tumor delineation in radiation therapy planning and response assessment.

Decades of research have confirmed that being a family caregiver is a stressful role. However, the point at which these stressors constitute a real risk for decreased mental health has not been established. The purpose of the present study was to determine a statistically valid cut-off score for the Zarit Burden Interview (ZBI) in order to identify family caregivers at risk for depression and in need of further assessment and intervention. The ZBI and the Geriatric Depression Scale or the CES-D were administered to three different populations of family caregivers of older adults: stroke caregivers (n=80), chronic obstructive pulmonary disease (COPD) caregivers (n=48), and general disability caregivers (n=70). Using three different statistical methods, a ZBI cut-off score was determined. Next, contingency analysis was used to compare depression scale scores and ZBI cut-offs for the three groups of caregivers. Findings suggest that a cut-off score ranging from 24-26 has significant predictive validity for identifying caregivers at risk for depression. A ZBI cut-off of 24 correctly identified 72% of caregivers with probable depression. The validity of ZBI cut-offs scores warrants further confirmation with larger samples. Valid cut-off scores would enable health care providers to assess family caregivers at risk and provide necessary interventions to improve their quality of life in this important role.

The Zarit Burden Interview (ZBI) is the instrument most widely used in North America and Europe for assessing the burden experienced by family caregivers who look after the community-residing impaired elderly. The Japanese version of the ZBI (J-ZBI) is the most widely used in Japan for the same purpose. We used data from 691 caregivers in relation to their caregiver burden with the 22-item J-ZBI. Following a factor analysis, the 8-item short version of the J-ZBI, the J-ZBI_8, was proposed with the following two factors: Personal strain (5 items) and Role strain (3 items). Cronbach's alpha of the J-ZBI_8 was 0.89, indicating the high reliability of this instrument. Pearson's correlation coefficient between J-ZBI and J-ZBI_8 was 0.93, and the same coefficient between J-ZBI_8 and item 22 (a single global burden) was 0.68. These data indicated that J-ZBI_8 had a high concurrent validity. In addition, caregivers who declared that they did not encounter any difficulties in looking after the impaired elderly had a significantly lower J-ZBI_8 score (3.45; SD = 4.57) than those who claimed that they had such difficulties (9.31; SD = 7.19) by the t-test; this indicated that J-ZBI_8 had a high construct validity. These results indicated that the short version, the J-ZBI_8, had a high reliability and validity. Therefore, the J-ZBI_8 produced results comparable to those of the full version, i.e. the J-ZBI. The shorter yet no less reliable and valid 8 item version will thus lead to easier administration of the instrument for assessing family caregiver burden in clinical settings.