Single isocenter HyperArc treatment of multiple intracranial metastases: Targeting accuracy.

PURPOSE/OBJECTIVES: (A) To examine the alignment accuracy of CBCT guidance for brain metastases with off centered isocenters, (B) to test dose delivery and targeting accuracy for single isocenter treatments with multiple brain metastases. We report the results of the end-to-end test for Truebeam stereotactic radiosurgery (SRS). MATERIALS/METHODS: An anthropomorphic CT head phantom was drilled with five MOSFET inserts and two PTW Pinpoint chamber inserts. The phantom was simulated, planned, and delivered. For the purpose of comparing the accuracy of alignment, CBCTs were acquired with the isocenter centered and offset superiorly 8 cm, inferiorly 8 cm, anteriorly 7 cm, posteriorly 7 cm, and right 5 cm. There were six degrees of freedom corrections applied to the plans, as well as intentional rotational and translational errors for dose comparisons. Dose accuracy checks were performed with MOSFET and PTW Pinpoint chamber, and targeting accuracy was assessed with GafChromic films. RESULT: (A) Compared to centered CBCT, off-centered CBCT scan showed some alignment errors, with a maximum difference of 0.6-degree pitch and 0.9 mm translation when the phantom was placed 8 cm inferior off center. (B) For the single isocenter plan, measured doses of the five MOSFET were 95%-100% of the planned dose, whereas the multiple isocenter plans were 96%-100%. With intentional setup errors of 1-degree pitch, doses were 97.1%-100.4% compared to the perfect setup. The same was found for the two pinpoint chamber readings with 1-degree rotation and 1 mm translation. (C) Targeting accuracy for targets at the isocenter is 0.67 mm, within the machine specification of 0.75 mm. Targeting accuracy for isocenters 6-12 cm away from the target is in the range 0.67-1.18 mm. CONCLUSION: (A) Single isocenter HyperArc treatments for multiple brain metastases are feasible and targeting accuracy is clinically acceptable. (B) The vertex in a cranial scan is very important for proper alignment.

Prevalence, determinants and consequences of problematic smartphone use among preschoolers (3-5 years) from Dhaka, Bangladesh: A cross-sectional investigation.

The problematic smartphone use (PSU) has been becoming a challenging health issue for preschoolers aged 3-5 years as it has severe adverse effect on their psychological, physical, and cognitive development. The scarcity of scientific research on this issue in the context of Bangladesh motivated the authors for conducting this cross-sectional study to explore the prevalence of PSU with its influential factors and adverse effects on preschooler's psychological and physical development based on primary data collected from 400 mothers. The multivariable ordinal logistic regression (OLR) was used to compute the adjusted likelihoods. The estimated prevalence of PSU was approximately 86 %, where about 29 % were severely problematic user. The likelihood of preschoolers' PSU was observed to increase with >1 h/day usage of smartphone by children (Adjusted Odds Ratio (AOR): 3.92). Other important factors were parental smartphone use, education, profession, family income, and mother's age. Both of moderate and severe PSU had adverse effect on preschoolers' health- severe PSU was found to increase the likelihood of psychological and physical problems by 6.03 and 3.29 times, respectively. The preschoolers with PSU reported to suffer from many physical and mental health problems such as attention deficit and hyperactivity disorder (ADHD), emotional instability, aggressiveness, depression, lack of control, impaired vision and hearing, obesity, body imbalance, and lack of brain development. It is now prime time to undertake strategic policies considering the findings for limiting the preschoolers' usage of smartphone, which will make Bangladesh susceptible to protect its future generation from harmful effects of PSU.

Is Halcyon feasible for single thoracic or lumbar vertebral segment SBRT?

PURPOSE: Halcyon linear accelerators employ intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) techniques. The Halcyon offers translational, but not rotational, couch correction, which only allows a 3 degrees of freedom (3-DOF) correction. In contrast, the TrueBeam (TB) linear accelerator offers full 6-DOF corrections. This study aims to evaluate the difference in treatment plan quality for single thoracic or lumbar vertebral segment SBRT between the Halcyon and TB linear accelerators. In addition, this study will also investigate the effect of patient rotational setup errors on the final plan quality. METHODS: We analyzed 20 patients with a single-level spine metastasis located between the T7 and L5 vertebrae near the spinal canal. The median planning target volume was 52.0 cm3 (17.9-138.7 cm3 ). The median tumor diameter in the axial plane was 4.6 cm (range 1.7-6.8 cm), in the sagittal plane was 3.3 cm (range 2-5 cm). The prescription doses were either 12-16 Gy in 1 fraction or 18-24 Gy in 3 fractions. All patients were treated on the TB linear accelerator with a 2.5 mm Multi-Leaf Collimator (MLC) leaf width. Treatment plans were retrospectively created for the Halcyon, which has a 5 mm effective MLC leaf width. The 20 patients had a total of 50 treatments. Analysis of the 50 cone beam computed tomography (CBCT) scans showed average rotational setup errors of 0.6°, 1.2°, and 0.8° in pitch, yaw, and roll, respectively. Rotational error in roll was not considered in this study, as the original TB plans used a coplanar volumetric modulated arc therapy (VMAT) technique, and each 1° of roll will contribute an error of 1/360. If a plan has 3 arcs, the contribution from errors in roll will be < 0.1%. To simulate different patient setup errors, for each patient, 12 CT image datasets were generated in Velocity AI with different rotational combinations at a pitch and yaw of 1°, 2°, and 3°, respectively. We recalculated both the TB and Halcyon plans on these rotated images.  The dosimetric plan quality was evaluated based on the percent tumor coverage, the Conformity Index (CI), Gradient Index (GI), Homogeneity index (HI), the maximum dose to the cord/cauda, and the volume of the cord/cauda receiving 8, 10, and 12 Gy (V8Gy, V10Gy and V12Gy). Paired t-tests were performed between the original and rotated plans with a significance level of 0.05. RESULTS: The Eclipse based VMAT plans on Halcyon achieved a similar target coverage (92.3 ± 3.0% vs. 92.4 ± 3.3%, p = 0.82) and CI (1.0 ± 0.1 vs. 1.1 ± 0.2, p = 0.12) compared to the TB plans. The Gradient index of Halcyon is higher (3.96 ±0.8) than TB (3.85 ±0.7), but not statistically significant. The maximum dose to the spinal cord/cauda was comparable (11.1 ± 2.8 Gy vs. 11.4 ± 3.6 Gy, p = 0.39), as were the V8Gy, V10Gy and V12Gy to the cord/cauda. The dosimetric influence of patient rotational setup error was statistically insignificant for rotations of up to 1° pitch/yaw (with similar target coverage, CI, max cord/cauda dose and V8Gy, V10Gy, V12Gy for cord/cauda). The total number of monitor units (MUs) for Halcyon (4998 ± 1688) was comparable to that of TB (5463 ± 2155) (p = 0.09). CONCLUSIONS: The Halcyon VMAT plans for a single thoracic or lumbar spine metastasis were dosimetrically comparable to the TB plans. Patient rotation within 1° in the pitch and yaw directions, if corrected by translation, resulted in insignificant dosimetric effects. The Halcyon linear accelerator is an acceptable alternative to TB for the treatment of single thoracic or lumbar spinal level metastasis, but users need to be cautious about the patient rotational setup error.  It is advisable to select patients appropriately, including only those with the thoracic or lumbar spine involvement and keeping at least 2 mm separation between the target and the cord/cauda. More margin is needed if the distance between the isocenter and cord/cauda is larger. It is advisable to place the planning isocenter close to the spinal canal to further mitigate the rotational error. SUMMARY: We simulated various scenarios of patient setup errors with different rotational combinations of pitch and yaw with 1°, 2°, and 3°, respectively. Rotation was corrected with translation only to mimic the Halcyon treatment scenario. Using the Halcyon for treating a tumor in a single thoracic or lumbar vertebral segment is feasible, but caution should be noted in patients requiring rotational corrections of > 1° in the absence of 6-DOF correction capabilities.

Intergenerational educational mobility in Bangladesh.

INTRODUCTION: Social mobility is considered as an important indicator of the economic development of a country. However, it varies widely across geographical regions and social groups in developing countries like Bangladesh. This paper intends to evaluate the intergenerational mobility in Bangladesh across generations. METHODS AND MATERIALS: This paper considers a nationally representative sample survey of 8,403 respondents (rural: 5,436 and urban: 2,967). The male and female respondents aged 23 years and above were included in the sample. The education attainment of a son or daughter as compared to their father's education level was considered as the measure of intergenerational mobility. Transition probability matrix and different social mobility indices were used to find out the intergenerational education mobility in Bangladesh. RESULTS: The findings reveal that approximately three-fourth (74.5%) of the respondents attained formal education, while more than half (58.3%) of the respondents' father was illiterate. The educational status of the respondents and their father who lived in urban areas was relatively better than who lived in rural areas. It is also observed that 91.2% and 81.6% of the intergenerational class movement was upward among sons and daughters respectively. The probability of a higher educated father will have a higher educated child is higher in urban areas than in rural areas of Bangladesh. The intergenerational mobility is higher in the primary, secondary, and higher secondary educational levels, though the illiterate and higher education levels are the least mobile classes. In addition, the limiting probabilities reveal that the chance of sending sons to schools by an illiterate father is less as compared to their daughters. Such difference is more obvious in the urban areas, i.e., it is highly likely that sons of the illiterate father are also illiterate. CONCLUSION: Bangladesh has been progressing remarkably in recent years. To keep the pace of the ongoing economic development in the country, it is necessary to give more attention to the illiterate people especially the girls who live in rural areas. The authors anticipate that the findings will be helpful for the policymakers as the relationship between inequality and intergenerational mobility is vital for several aspects of the economic development of a country.

Optimization of the accelerated partial breast brachytherapy fractionation considering radiation effect on planning target and organs at risk.

The same fractionation scheme of accelerated partial breast irradiation (APBI) with brachytherapy is usually applied to APBI patients without considering the radiaton effect on the planning target and organs at risk (OARs) for an individual patient. The purpose of this study is to report the results of optimization of the fractionation scheme by evaluating the radiation effect on target and OARs with a modified linear-quadratic model, universal survival curve (USC), based on dose-volume histograms (DVHs). Ten breast patients treated with multilumen balloon brachytherapy were selected. The minimum skin and chest wall/rib (CW/rib) spacing ranged from 2.5 to 14.3 mm and from 0.5 to 25.0 mm, respectively. The USC model parameters were set as: (1) breast:α = 0.3, ß = 0.05; (2) skin: acute reaction α = 0.101, ß = 0.009; late reaction α = 0.064, ß = 0.029; (3) CW/rib: α = 0.3, ß = 0.12. Boundary dose Dt was 6 Gy for both target and OARs. The relation between radiation effects on the target (ET) and OARs (EOAR) were plotted for fraction numbers (N) from 1 to 20. If ET is set at a certain value, the fractionation that results in a minimum EOAR value corresponds to the optimal fractionation. The results show that the optimal fractionation is different for different OAR damage effects. For most of the patients, N = 2 is best for minimizing skin acute reactions while N = 20 is best for minimizing skin late reactions. N varies from 3 to 20 among patients for minimizing CW/rib toxicity. The determined unique optimal N for treatment delivery was found to vary from 1 to 20 among these 10 patients resulted from balancing the different damage effects considering the spatial dose for a given patient geometry. Optimal fractionation can be achieved for an individual patient by evaluating the radiation effect on tumor and OARs with the USC model based on the patient specific DVHs with APBI brachytherapy.

A Mobile Alert System for Preparing the Delivery of Radiation Mitigators.

BACKGROUND/AIM: A mobile system allowing hospital medical personnel to prepare for the administration of radiation mitigators prior to receiving casualties is desirable. MATERIALS AND METHODS: We evaluated a portable spectroscopic personal radiation detector for use as an ambulance-based unit for early detection and identification of gamma radiation. We tested the sensitivity, time-to-identification, and radionuclide identification accuracy rates, change in detector response to vehicle operation, interference from cardiac equipment, and internal versus external radiation source location. RESULTS: We detected radiation sources in each of 119 trials using a humanoid phantom in a moving ambulance with a primary radionuclide identification accuracy of 96%. Typical identification time was around two minutes (149±95 s). CONCLUSION: Our observations suggest this mobile system is a potential pre-hospital arrival tool allowing for rapid preparation of radiation mitigators.

Dosimetric definitions of total lung volumes in calculating parameters predictive for radiation-induced pneumonitis.

OBJECTIVES: The volume of normal lung receiving 20 Gy (V20) and the mean lung dose (MLD) represent dosimetric parameters used for identifying risk of radiation pneumonitis. However, the total lung volume for dosimetric analysis has been defined differently. Herein we investigate to quantify the dosimetric differences when analysis is based on either definition (ie, excluding planning target volume [PTV] vs. gross tumor volume [GTV] from the total bilateral lung volume). METHODS: Sixty-one patients with lung cancer who had undergone definitive radiation therapy were retrospectively reviewed. Dosimetric parameters were calculated when excluding GTV or PTV from the total bilateral lung volume. RESULTS: Median GTV to PTV margin was 1.3 cm (range, 0.4 to 3.8 cm). Median heterogeneity-corrected RT dose was 74 Gy with the median GTV of 110 mL (range, 13.79 to 665.8 mL) and the median PTV of 346 mL (range, 39.8 to 1258 mL).The MLD, V5, V10, V20, and V30 were all slightly higher and significant when excluding GTV from the total bilateral lung volume compared with similar dosimetric parameters when excluding PTV (P<0.001). Average MLD was 14.8 and 16.7 Gy when excluding PTV and GTV, respectively. Mean V5, V10, V20, and V30 were 49.8%, 38%, 25%, and 18.8% when excluding PTV versus 51.3%, 40%, 28%, and 21.5% when excluding GTV. There were 4 patients with clinical pneumonitis and all had the V20>23% when excluding the PTV versus the V20>27% when excluding the GTV from total bilateral lung volume. CONCLUSIONS: A small but significant difference exists between the 2 approaches used to calculate dosimetric variables for lung dose. This difference should be taken into account when comparing dosimetric information between different institutions and when optimizing treatment plans.

Agreement between TOAST and CCS ischemic stroke classification: the NINDS SiGN study.

OBJECTIVE: The objective of this study was to assess the level of agreement between stroke subtype classifications made using the Trial of Org 10172 Acute Stroke Treatment (TOAST) and Causative Classification of Stroke (CCS) systems. METHODS: Study subjects included 13,596 adult men and women accrued from 20 US and European genetic research centers participating in the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Genetics Network (SiGN). All cases had independently classified TOAST and CCS stroke subtypes. Kappa statistics were calculated for the 5 major ischemic stroke subtypes common to both systems. RESULTS: The overall agreement between TOAST and CCS was moderate (agreement rate, 70%; κ = 0.59, 95% confidence interval [CI] 0.58-0.60). Agreement varied widely across study sites, ranging from 28% to 90%. Agreement on specific subtypes was highest for large-artery atherosclerosis (κ = 0.71, 95% CI 0.69-0.73) and lowest for small-artery occlusion (κ = 0.56, 95% CI 0.54-0.58). CONCLUSION: Agreement between TOAST and CCS diagnoses was moderate. Caution is warranted when comparing or combining results based on the 2 systems. Replication of study results, for example, genome-wide association studies, should utilize phenotypes determined by the same classification system, ideally applied in the same manner.

Improved survival of mice after total body irradiation with 10 MV photon, 2400 MU/min SRS beam.

BACKGROUND/AIM: We evaluated the radiobiological effects of stereotactic radiosurgery (SRS) photon beams on survival of C57BL/6NTac mice following total body irradiation. MATERIALS AND METHODS: Survival of Lewis lung carcinoma (3LL) cells was tested after irradiation using 6 MV: 300 MU/min or 1400 MU/min; or 10 MV: 300 MU/min or 2400 MU/min. Survival of C57BL/6NTac mice after a dose which is lethal to 50% of the mice in 30 days (LD50/30) (9.25 Gy) total body irradiation (TBI) and 21 Gy to orthotopic 3LL tumors was tested. We quantitated levels of organ-specific gene transcripts by Real Time Polymerase Chain Reaction (RT-PCR). RESULTS: While 3LL cell survival and inhibition of orthotopic tumor growth was uniform, 10 MV photons at 2400 MU/min TBI led to significantly greater survival (p=0.0218), with higher levels of intestinal (Sod2), (Gpx1), (Nrf2), and (NFκB) RNA transcripts. CONCLUSION: Clinical 10 MV-2400 cGy/min SRS beams led to unexpected protection of mice on TBI and increased radioprotective gene transcripts.

Public views of health system issues in four Asian countries.

To elicit the public's views on health system issues, we conducted an opinion poll survey in Bangladesh, Mongolia, Nepal, and Sri Lanka. We focused on health inequalities. The results show high levels of dissatisfaction with government health services in all four of the countries. Access to government health services was an important concern. A sizable number of respondents reported that their governments did not consider their views at all in shaping health care services. The policy implications of the study findings are discussed.

Who pays for health care in Asia?

We estimate the distributional incidence of health care financing in 13 Asian territories that account for 55% of the Asian population. In all territories, higher-income households contribute more to the financing of health care. The better-off contribute more as a proportion of ability to pay in most low- and lower-middle-income territories. Health care financing is slightly regressive in three high-income economies with universal social insurance. Direct taxation is the most progressive source of finance and is most so in poorer economies. In universal systems, social insurance is proportional to regressive. In high-income economies, the out-of-pocket (OOP) payments are proportional or regressive while in low-income economies the better-off spend relatively more OOP. But in most low-/middle-income countries, the better-off not only pay more, they also get more health care.

Maternal education and child healthcare in Bangladesh.

Child health is one of the important indicators for describing mortality conditions, health progress and the overall social and economic well being of a country. During the last 15 years, although Bangladesh has achieved a significant reduction in the child mortality rate, the levels still remain very high. The utilization of qualified providers does not lead to the desired level; only a third relies on qualified providers. This study is mainly aimed at investigating the influence of maternal education on health status and the utilization of child healthcare services in Bangladesh. This study is based on the data of the Household Income Expenditure Survey (HIES) conducted by the Bangladesh Bureau of Statistics (BBS) during 2000. The analysis of the findings reveals that 19.4% of the children under five reported sickness during 30 days prior to the survey date. Moreover, approximately one out of every thirteen children suffers from diarrhoea in the country. It is striking to note that a significant portion of the parents relied on unqualified or traditional providers for the children's healthcare because of low cost, easy accessibility and familiarity of the services. The study suggests that maternal education is a powerful and significant determinant of child health status in Bangladesh. Maternal education also positively affects the number of children receiving vaccination. In order to improve the health condition of children in Bangladesh maternal education should be given top priority. The public policies should not just focus on education alone, but also consider other factors, such as access to health facilities and quality of services. Health awareness campaign should be strengthened as part of the public health promotion efforts. More emphasis should also be given to government-NGO (Non Government Organization) partnerships that make vaccination programs successful and, thereby, reduce the incidence of preventable diseases.

Catastrophic payments for health care in Asia.

Out-of-pocket (OOP) payments are the principal means of financing health care throughout much of Asia. We estimate the magnitude and distribution of OOP payments for health care in fourteen countries and territories accounting for 81% of the Asian population. We focus on payments that are catastrophic, in the sense of severely disrupting household living standards, and approximate such payments by those absorbing a large fraction of household resources. Bangladesh, China, India, Nepal and Vietnam rely most heavily on OOP financing and have the highest incidence of catastrophic payments. Sri Lanka, Thailand and Malaysia stand out as low to middle income countries that have constrained both the OOP share of health financing and the catastrophic impact of direct payments. In most low/middle-income countries, the better-off are more likely to spend a large fraction of total household resources on health care. This may reflect the inability of the poorest of the poor to divert resources from other basic needs and possibly the protection of the poor from user charges offered in some countries. But in China, Kyrgyz and Vietnam, where there are no exemptions of the poor from charges, they are as, or even more, likely to incur catastrophic payments.

Effect of payments for health care on poverty estimates in 11 countries in Asia: an analysis of household survey data.

BACKGROUND: Conventional estimates of poverty do not take account of out-of-pocket payments to finance health care. We aimed to reassess measures of poverty in 11 low-to-middle income countries in Asia by calculating total household resources both with and without out-of-pocket payments for health care. METHODS: We obtained data on payments for health care from nationally representative surveys, and subtracted these payments from total household resources. We then calculated the number of individuals with less than the internationally accepted threshold of absolute poverty (US1 dollar per head per day) after making health payments. We also assessed the effect of health-care payments on the poverty gap--the amount by which household resources fell short of the 1 dollar poverty line in these countries. FINDINGS: Our estimate of the overall prevalence of absolute poverty in these countries was 14% higher than conventional estimates that do not take account of out-of-pocket payments for health care. We calculated that an additional 2.7% of the population under study (78 million people) ended up with less than 1 dollar per day after they had paid for health care. In Bangladesh, China, India, Nepal, and Vietnam, where more than 60% of health-care costs are paid out-of-pocket by households, our estimates of poverty were much higher than conventional figures, ranging from an additional 1.2% of the population in Vietnam to 3.8% in Bangladesh. INTERPRETATION: Out-of-pocket health payments exacerbate poverty. Policies to reduce the number of Asians living on less than 1 dollar per day need to include measures to reduce such payments.