The process, outcomes and context of the sanitation change induced by the Swachh Bharat Mission in rural Jharkhand, India.

BACKGROUND: The Indian Swachh Bharat Mission (SBM) was launched in 2014 with the goal to make India open defecation (OD) free by October 2019. Although it is known that the ambitious goal was not achieved, the nature of the sanitation change brought about by the SBM in different parts of India is poorly understood. One reason is a dearth of case studies that would shed light on the performance of the SBM simultaneously across its different domains. This article provides an example of such study. Employing a Process, Outcomes, Context approach, the objective is to understand the process and outcomes of the SBM-induced sanitation change in a specific context of rural Jharkhand. METHODS: The study utilizes data collected through field research conducted in the rural areas of Ranchi district, Jharkhand, a state in east-central India. This data was obtained via repeated cross-sectional household surveys conducted at the beginning and at the end of the SBM, supplemented by key informant interviews with SBM stakeholders. FINDINGS: We identified political support of SBM implementation and its acceptance amongst the population. Female community workers became key agents of SBM implementation at local level. The SBM increased toilet coverage in the study area from 15% to 85% and lowered the OD rate from 93% to 26%. It substantially reduced structural inequalities in access to toilets, furthered social sanitation norms, improved some of the attitudes towards toilet use, but impacted less on hygiene and sanitation knowledge. The implementation mainly concentrated on the construction of subsidized toilets but less on improving public understanding of safe sanitation practices. CONCLUSIONS: Although the SBM reduced sanitation inequalities in access to toilets in the study area, the behaviour change component was underplayed, focusing more on spreading normative sanitation messages and less on public education. Sustainability of the observed sanitation change remains a key question for the future. This article calls for more systematic production of geographically situated knowledge on the performance of sanitation interventions.

Promotion of market-based sanitation in Ethiopia: a case study from Wolaita zone.

Ethiopia increased the availability of latrines notably, but the sanitation facilities rarely meet hygienic standards. Therefore, the market-based sanitation (MBS) programme has been implemented across the country for nearly a decade to expand the market and boost the demand for hygienic sanitation products and services. While it does not seem that the MBS would bring any notable change in sanitation conditions so far, its implementation challenges are not adequately understood. To address this gap, this article delves into the grassroots-level implementation of MBS in the Wolaita zone. The study relies on qualitative data gathered through interviews with various stakeholders, examining both demand- and supply-side challenges. Some issues identified were external to MBS implementation, such as high inflation and an unstable political and security situation in Ethiopia. Additionally, the study reveals that more general deficiencies of the Ethiopian health extension program, including the stress and discouragement of local change agents (health extension workers, health development army members) due to workloads and low remuneration, have adversely impacted MBS delivery. The implementation of MBS has also not effectively addressed the affordability of hygienic sanitation products. On the supply side, economic constraints and organizational inefficiencies have hindered the development of the sanitation market, preventing it from reaching a critical mass. Our research suggests that MBS alone will not suffice to improve sanitation in Ethiopia.

Fetal Dose Evaluation for Pregnant Patients on Leksell Gamma Knife Perfexion/Icon.

INTRODUCTION: It is a normal procedure to avoid the application of ionizing radiation during pregnancy. In very rare occasions, treatment can be performed, but doses to the fetus must be evaluated and reported, and the patient must sign informed consent. There can occur two types of damage caused by ionizing radiation - deterministic and stochastic effects. Deterministic effects may occur after reaching a certain threshold (100 mGy for this study); meanwhile, stochastic effects have no limit and their probability rises with dose. This study focuses on deterministic effects. CASE PRESENTATIONS: This study compares the dose measured on phantom for the area of the pelvis and the dose measured on 3 patients with dosimeters positioned on the pelvis irradiated on Leksell Gamma Knife Perfexion/Icon. The mean dose for measurement on phantom for the pelvis was 0.73 ± 0.76 mGy, and for the patients, it was 1.28 mGy, 0.493 mGy, and 0.549 mGy which is 80 times lower, 200 times lower, and 180 times lower than the threshold for deterministic effects, respectively. CONCLUSION: The measurement carried on phantom served as the base for drafting informed consent and provided initial proof that treatment can be safely delivered. Measurements performed on patients only confirmed that irradiation of pregnant patients on Leksell Gamma Knife Perfexion/Icon is safe relative to the deterministic effects. Nevertheless, pregnant patients should be treated with ionizing radiation only in very extraordinary situations.

Household-level sanitation in Ethiopia and its influencing factors: a systematic review.

BACKGROUND: Within the past two decades, Ethiopia has achieved one of the fastest reductions of open defecation worldwide. This change can be attributed to the implementation of a national sanitation strategy that focused on facilitating community demand for latrine adoption and use of basic self-constructed latrines but less on other preconditions of hygienic sanitation. Recognition of sanitation by policymakers also catalyzed primary research in this area. As such, the synthesis of the available evidence is both warranted and possible. In this article, we thus decided to assess available primary evidence on the household-level sanitation in Ethiopia and its influencing factors. METHODS: We searched primary studies that present findings on the role of factors influencing household-level sanitation outcomes in Ethiopia. We typologically classified sanitation outcomes analyzed in identified literature and computed pooled estimates for the most prevalent ones (measures of latrine availability and use). We characterized thematic types (themes and sub-themes) of influential sanitation drivers and used network analysis to examine the relational patterns between sanitation outcomes and their influencing factors. FINDINGS: We identified 37 studies that met our inclusion criteria-all but one published after 2009. The general latrine coverage pooled across 23 studies was 70% (95% CI: 62-77%), the share of improved latrines pooled across 15 studies was 55% (95% CI: 41-68%), and latrine use pooled across 22 studies was 72% (95% CI: 64-79%). Between-study heterogeneity was high, and no time trends were identified. The identified sanitation outcomes were classified into eight types and factors reported to influence these outcomes were classified into 11 broader themes and 43 more specific sub-themes. Factors around the quality of latrines represented the most frequent sub-theme of consequential drivers. We found that the available research focused predominantly on outcomes concerning the initial adoption and use of basic latrines, emulating the main focus of national sanitation strategy. By contrast, research on drivers of the sustainability of sanitation change and, in particular, on the upgrading of latrines, has been rare despite its urgency. There is a high need to redirect the focus of sanitation research in Ethiopia towards understanding these factors on both the demand and supply side.

A System Using Artificial Intelligence to Detect and Scare Bird Flocks in the Protection of Ripening Fruit.

Flocks of birds may cause major damage to fruit crops in the ripening phase. This problem is addressed by various methods for bird scaring; in many cases, however, the birds become accustomed to the distraction, and the applied scaring procedure loses its purpose. To help eliminate the difficulty, we present a system to detect flocks and to trigger an actuator that will scare the objects only when a flock passes through the monitored space. The actual detection is performed with artificial intelligence utilizing a convolutional neural network. Before teaching the network, we employed videocameras and a differential algorithm to detect all items moving in the vineyard. Such objects revealed in the images were labeled and then used in training, testing, and validating the network. The assessment of the detection algorithm required evaluating the parameters precision, recall, and F1 score. In terms of function, the algorithm is implemented in a module consisting of a microcomputer and a connected videocamera. When a flock is detected, the microcontroller will generate a signal to be wirelessly transmitted to the module, whose task is to trigger the scaring actuator.

The Potential of Utilizing Air Temperature Datasets from Non-Professional Meteorological Stations in Brno and Surrounding Area.

An increasing number of individuals and institutions own or operate meteorological stations, but the resulting data are not yet commonly used in the Czech Republic. One of the main difficulties is the heterogeneity of measuring systems that puts in question the quality of outcoming data. Only after a thorough quality control of recorded data is it possible to proceed with for example a specific survey of variability of a chosen meteorological parameter in an urban or suburban region. The most commonly researched element in the given environment is air temperature. In the first phase, this paper focuses on the quality of data provided by amateur and institutional stations. The following analyses consequently work with already amended time series. Due to the nature of analyzed data and their potential use in the future it is opportune to assess the appropriateness of chronological and possibly spatial interpolation of missing values. The evaluation of seasonal variability of air temperature in the scale of Brno city and surrounding area in 2015-2017 demonstrates, that the enrichment of network of standard (professional) stations with new stations may significantly refine or even revise the current state of knowledge, for example in the case of urban heat island phenomena. A cluster analysis was applied in order to assess the impact of localization circumstances (station environment, exposition, etc.) as well as typological classification of the set of meteorological stations.

Risk of radiation-associated intracranial malignancy after stereotactic radiosurgery: a retrospective, multicentre, cohort study.

BACKGROUND: A major concern of patients who have stereotactic radiosurgery is the long-term risk of having a secondary intracranial malignancy or, in the case of patients with benign tumours treated with the technique, the risk of malignant transformation. The incidence of stereotactic radiosurgery-associated intracranial malignancy remains unknown; therefore, our aim was to estimate it in a population-based study to assess the long-term safety of this technique. METHODS: We did a population-based, multicentre, cohort study at five international radiosurgery centres (Na Homolce Hospital, Prague, Czech Republic [n=2655 patients]; Ruber International Hospital, Madrid, Spain [n=1080], University of Pittsburgh Medical Center, Pittsburgh, PA, USA [n=1027]; University of Virginia, Charlottesville, VA, USA [n=80]; and NYU Langone Health System, New York, NY, USA [n=63]). Eligible patients were of any age, and had Gamma Knife radiosurgery for arteriovenous malformation, trigeminal neuralgia, or benign intracranial tumours, which included vestibular or other benign schwannomas, WHO grade 1 meningiomas, pituitary adenomas, and haemangioblastoma. Patients were excluded if they had previously had radiotherapy or did not have a minimum follow-up time of 5 years. The primary objective of the study was to estimate the incidence of stereotactic radiosurgery-associated intracranial malignancy, including malignant transformation of a benign lesion or development of radiation-associated secondary intracranial cancer, defined as within the 2 Gy isodose line. Estimates of age-adjusted incidence of primary CNS malignancies in the USA and European countries were retrieved from the Central Brain Tumor Registry of the United States (CBTRUS) and the International Agency for Research on Cancer (IARC) Global Cancer statistics. FINDINGS: Of 14 168 patients who had Gamma Knife stereotactic radiosurgery between Aug 14, 1987, and Dec 31, 2011, in the five contributing centres, 4905 patients were eligible for the analysis (had a minimum follow-up of 5 years and no history of previous radiation therapy). Diagnostic entities included vestibular schwannomas (1011 [20·6%] of 4905 patients), meningiomas (1490 [30·4%]), arteriovenous malformations (1089 [22·2%]), trigeminal neuralgia (565 [11·5%]), pituitary adenomas (641 [13·1%]), haemangioblastoma (29 [0·6%]), and other schwannomas (80 [1·6%]). With a median follow-up of 8·1 years (IQR 6·0-10·6), two (0·0006%) of 3251 patients with benign tumours were diagnosed with suspected malignant transformation and one (0·0002%) of 4905 patients was considered a case of radiosurgery-associated intracranial malignancy, resulting in an incidence of 6·87 per 100 000 patient-years (95% CI 1·15-22·71) for malignant transformation and 2·26 per 100 000 patient-years (0·11-11·17) for radiosurgery-associated intracranial malignancy. Two (0·0004%) of 4905 patients developed intracranial malignancies, which were judged unrelated to the radiation field. Overall incidence of radiosurgery-associated malignancy was 6·80 per 100 000 patients-years (95% CI 1·73-18·50), or a cumulative incidence of 0·00045% over 10 years (95% CI 0·00-0·0034). The overall incidence of 6·8 per 100 000, which includes institutions from Europe and the USA, after stereotactic radiosurgery was found to be similar to the risk of developing a malignant CNS tumour in the general population of the USA and some European countries as estimated by the CBTRUS and IARC data, respectively. INTERPRETATION: These data show that the estimated risk of an intracranial secondary malignancy or malignant transformation of a benign tumour in patients treated with stereotactic radiosurgery remains low at long-term follow-up, and is similar to the risk of the general population to have a primary CNS tumour. Although prospective cohort studies with longer follow-up are warranted to support the results of this study, the available evidence suggests the long-term safety of stereotactic radiosurgery and could support physicians counselling patients on Gamma Knife stereotactic radiosurgery. FUNDING: None.

Comprehending practitioners' assessments of community-led total sanitation.

Around 2.3 billion people in developing countries still lack access to improved sanitation facilities and almost one billion practice open defecation (OD). The Community-Led Total Sanitation (CLTS) has recently become a particularly popular approach used in more than 60 countries. CLTS is a behavior-change approach that aims to ignite community action and make OD socially unacceptable without providing any external financial or material support to individual households. CLTS is sometimes perceived as a revolutionary approach that has proven to be highly cost-effective in abolishing OD. However, it has been criticized for its use of unethical practices and questioned with respect to the sustainability of its outcomes and the limited health benefits it can generate. Based on semi-structured interviews with development workers experienced in the implementation of CLTS in 14 different countries, this paper seeks to examine practical views on the issues surrounding this approach. We found that despite acknowledging some of the controversies and the possibly limited sustainability of results, CLTS is generally considered an effective and satisfactory tool for improving sanitation conditions. Practitioners first of all accentuate the normative importance of the elimination of OD attained through CLTS without weighting on (the absence of) evidence on the longer term effects or impacts on health. However, a need for various modifications of CLTS according to local social and natural environments was strongly expressed, including changes that go against the core principles of CLTS like no subsidies and no technical assistance principles.

Assessment of MR stereotactic imaging and image co-registration accuracy for 3 different MR scanners by 3 different methods/phantoms: phantom and patient study.

OBJECTIVEThe aim of this study was to compare 3 different methods to assess the geometrical distortion of two 1.5-T and one 3-T magnetic resonance (MR) scanners and to evaluate co-registration accuracy. The overall uncertainty of each particular method was also evaluated.METHODSThree different MR phantoms were used: 2 commercial CIRS skull phantoms and PTGR known target phantom and 1 custom cylindrical Perspex phantom made in-house. All phantoms were fixed in the Leksell stereotactic frame and examined by a Siemens Somatom CT unit, two 1.5-T Siemens (Avanto and Symphony) MRI systems, and one 3-T Siemens (Skyra) MRI system. The images were evaluated using Leksell GammaPlan software, and geometrical deviation of the selected points from the reference values were determined. The deviations were further investigated for both definitions including fiducial-based and co-registration-based in the case of the CIRS phantom images. The same co-registration accuracy assessment was also performed for a clinical case. Patient stereotactic imaging was done on 3-T Skyra, 1.5-T Avanto, and CT scanners.RESULTSThe accuracy of the CT scanner was determined as 0.10, 0.30, and 0.30 mm for X, Y, and Z coordinates, respectively. The total estimated uncertainty in distortion measurement in one coordinate was determined to be 0.32 mm and 0.14 mm, respectively, for methods using and not using CT as reference imaging. Slightly more significant distortions were observed when using the 3-T than either 1.5-T MR units. However, all scanners were comparable within the estimated measurement error. Observed deviation/distortion for individual X, Y, and Z stereotactic coordinates was typically within 0.50 mm for all 3 scanners and all 3 measurement methods employed. The total radial deviation/distortion was typically within 1.00 mm. Maximum total radial distortion was observed when the CIRS phantom was used; 1.08 ± 0.49 mm, 1.15 ± 0.48 mm, and 1.35 ± 0.49 mm for Symphony, Avanto, and Skyra, respectively. The co-registration process improved image stereotactic definition in a clinical case in which fiducial-based stereotactic definition was not accurate; this was demonstrated for 3-T stereotactic imaging in this study. The best results were shown for 3-T MR image co-registration with CT images improving image stereotactic definition by about 0.50 mm. The results obtained with patient data provided a similar trend of improvement in stereotactic definition by co-registration.CONCLUSIONSAll 3 methods/phantoms used were evaluated as satisfactory for the image distortion measurement. The method using the PTGR phantom had the lowest uncertainty as no reference CT imaging was needed. Image co-registration can improve stereotactic image definition when fiducial-based definition is not accurate.

Gamma knife radiosurgery for local recurrence of glioblastoma.

OBJECTIVE: Local recurrence of glioblastoma is observed in most patients after standard oncologic treatment (surgery, chemotherapy and radiotherapy). Stereotactic radiosurgery with the Leksell Gamma Knife (SRS with LGK) was used to treat recurrent tumors in selected cases, and retrospective analysis of treatment outcome was performed. METHODS: Altogether 126 patients were treated for glioblastoma at our center from 1992-2014. Sixty-nine patients (55%) were male and 57 (45%) female, with a median age of 56 years (range 17-80 years). Prior to LGK radiosurgery, 123 (98%) underwent surgery, 126 (100%) radiotherapy and 116 (92%) chemotherapy. The median Karnofsky score before LGK radiosurgery was 90% (range 50-100), and the median time from GBM diagnosis to LGK radiosurgery was 12 months (range 1-96 months). The median tumor volume was 3.75 cm3 (range 0.04-37.10 cm3). LGK radiosurgery was performed in a single fraction with a median minimal tumor dose of 12 Gy (range 10-25 Gy) on a median 50% (range 40-86%) isodose line. Two and more LGK radiosurgeries were performed in 19 (15%) cases, a median interval of 9.6 months (range 2-45 months) from the initial LGK radiosurgery. The median prescribed dose in these patients was 12.6 Gy (range 10-15 Gy), and the median volume 5.8 cm3 (range 0.1-13.7 cm3). RESULTS: The median survival from GBM diagnosis was 20 months (range 6-237 months). The median survival after LGK radiosurgery was 7 months (range 1-223 months). The one year survival after LGK radiosurgery was 27%, 2 years 8%, and more than 3 years 4%. Tumor regression on MR images was observed in 17% of patients at a median interval of 7 months. The median interval to tumor progression on MR images after LGK treatment was 8.5 months. No treatment-related radionecrosis with expansive behaviour was detected after radiosurgery. CONCLUSION: We show that LGK radiosurgery is a safe palliative treatment modality in patients with recurrent GBM.

Social determinants of environmental health: A case of sanitation in rural Jharkhand.

An estimated 56% of households in rural India defecated in the open in 2015, making India the most significant contributor to the global sanitation burden. This cross-sectional study uses data collected in 2016 from 499 households in rural Jharkhand to understand the constraints of latrine adoption and drivers of sanitation preferences (plans to adopt toilets and willingness to pay for toilets). Focusing on a region with a large tribal population, the study examines two types of predictors, namely structural factors (objective socioeconomic, sociocultural and ecological characteristics) and psychosocial drivers (perceived unaffordability of toilet, hygiene and sanitation knowledge, perceived health risks, attitudes, both descriptive and injunctive social norms, and perceived water stress). We find that structural constraints related to educational, economic and sociocultural inequalities predict toilet ownership. Low sanitation rates can neither be attributed to a lack of expressed demand nor lack of recognition of the disadvantages of open defecation. Similarly, variations in sanitation preferences are neither explained by differences in hygiene and sanitation knowledge nor by understandings of sanitation health risks. We find that perceived unaffordability, attitudes (perceived benefits of toilet and disadvantages of OD) and perceived descriptive social norms are of key importance. This implies a potential for persuasive strategies that manipulate social norms around sanitation, particularly if they simultaneously address perceptions around financial unaffordability of toilets and around the benefits of toilets. Importantly, however, attempts to change sanitation preferences by acting on forces of social (dis)approval (i.e. through perceived injunctive social norms) may be ineffective and generate negative unintended consequences.

Comparison of the Convolution algorithm with TMR10 for Leksell Gamma knife and dosimetric verification with radiochromic gel dosimeter.

The Convolution algorithm, implemented in Leksell GammaPlan® ver. Here, 10, is the first algorithm for Leksell Gamma Knife that takes heterogeneities into account and models dose build-up effects close to tissue boundaries. The aim of this study was preliminary comparison of the Convolution and TMR10 algorithms for real clinical cases and dosimetric verification of the algorithms, using measurements in a phantom. A total of 25 patients involved in comparison of the Convolution and TMR10 algorithms were divided into three groups: patients with benign tumors close to heterogeneities, patients with functional disorders, and patients with tumors located far from heterogeneities. Differences were observed especially in the group of patients with tumors close to heterogeneities, where the difference in maximal dose to critical structures for the Convolution algorithm was up to 15% compared to the TMR10 algorithm. Dosimetric verification of the algorithm was performed, using a radiochromic gel dosimeter based on Turnbull blue dye in a special heterogeneous phantom. Relative dose distributions measured with the radiochromic gel dosimeter agreed very well with both the TMR10 and Convolution calculations. We observed small discrepancies in the direction in which the largest inhomogeneity was positioned. Verification results indicated that the Convolution algorithm provides a different dose distribution, especially in regions close to heterogeneities and particularly for lower isodose volumes. However, the results obtained with gamma analyses in the gel dosimetry experiment did not verify the assumption that the Convolution algorithm provides more accurate dose calculation.

Contextual factors and motivations affecting rural community sanitation in low- and middle-income countries: A systematic review.

BACKGROUND: Unsafe management of human faecal waste represents a major risk for public health, particularly in low- and middle-income countries. Efforts to improve sanitation conditions are considerably sensitive to contextual specifics of natural and social environments. This review operationalises, analyses, and synthesises evidence of how contextual factors and motivations affect different sanitation outcomes with a specific focus on community approaches to rural sanitation. METHODS AND FINDINGS: We operationalised contextual factors and motivations as determinants that influence sanitation conditions independently of the examined intervention. We conducted a systematic search of both peer-reviewed and grey literature with no restriction on the methods After screening the titles and abstracts of 19,198 records obtained through initial searches, we scrutinised the full content of 621 studies for relevance. While 102 of these studies qualified to be assessed for risk of bias and information content, ultimately, just 40 studies met our eligibility criteria. Of these 40 studies from 16 countries, 26 analysed specific interventions and 14 were non-interventional. None of the experimental studies reported the effects of contextual factors or motivations as operationalised in this study and only observational evidence was thus used in our review. We found that sanitation interventions are typically seen as the principal vehicles of change, the main instruments to fix 'deviant' behaviour or ensure access to infrastructure. The programmatic focus of this study on sanitation determinants that act independently of specific interventions questions this narrow understanding of sanitation dynamics. We identified 613 unique observations of quantitatively or qualitatively established relationships between certain contextual factors or motivations and 12 different types of sanitation outcomes. The sanitation determinants were classified into 77 typologically similar groups clustered into 12 broader types and descriptively characterised. We developed a graphical synthesis of evidence in the form of a network model referred to as the sanitation nexus. The sanitation nexus depicts how different groups of determinants interlink different sanitation outcomes. It provides an empirically derived conceptual model of sanitation with an aggregate structure indicating similarities and dissimilarities between sanitation outcomes with respect to how their sets of underlying determinants overlap. CONCLUSION: This study challenged the understanding of context as merely something that should be controlled for. Factors that affect targeted outcomes independently of the analysed interventions should be scrutinised and reported. This particularly applies to interventions involving complex human-environment interactions where generalisability is necessarily indirect. We presented a novel approach to comprehending the contextual factors and motivations which influence sanitation outcomes. Our approach can be analogously applied when mapping and organising underlying drivers in other areas of public and environmental health. The sanitation nexus derived in this study is designed to inform practitioners and researchers about sanitation determinants and the outcomes they influence.

The Role of Perceived Social Norms in Rural Sanitation: An Explorative Study from Infrastructure-Restricted Settings of South Ethiopia.

The perception of social sanitation norms (PSSNs) around unacceptability of open defecation has been a key aspect of recent sanitation interventions. However, underlying mechanisms through which "reconstructed" PSSNs affect sanitation outcomes have been a black box. This explorative cross-sectional study examines direct and indirect links between PSSNs and sanitation safety using data from structured interviews and observations in 368 households in rural South Ethiopia. In addition to a positive association between PSSNs and sanitation safety, we propose and examine the following two mechanisms: First, we confirm a potentially adverse feedback of PSSNs on future sanitation safety by enhancing the emotional satisfaction with current sanitation practice (satisfaction independent of the functionality of sanitation facilities). Second, inspired by the social amplification/attenuation of risk framework, we demonstrate that PSSNs work as a "social filter" that can amplify or attenuate the effects of other variables targeted in sanitation interventions such as perceived health-related and non-health risks and benefits associated with open defecation and private latrine ownership, respectively, and factual hygiene and sanitation knowledge. These findings imply that PSSNs are not only important per se, but they are also important instrumentally because sanitation outcomes depend upon the capacity of social influences to shape the perception of sanitation risks and benefits and sanitation-related awareness in desirable ways. The mechanisms outlined in this paper as well as the sustainability of sanitation outcomes depend on whether and how social sanitation norms are internalized.

Two-year experience with the commercial Gamma Knife Check software.

The Gamma Knife Check software is an FDA approved second check system for dose calculations in Gamma Knife radiosurgery. The purpose of this study was to evaluate the accuracy and the stability of the commercial software package as a tool for independent dose verification. The Gamma Knife Check software version 8.4 was commissioned for a Leksell Gamma Knife Perfexion and a 4C unit at the University of Pittsburgh Medical Center in May 2012. Independent dose verifications were performed using this software for 319 radiosurgery cases on the Perfexion and 283 radiosurgery cases on the 4C units. The cases on each machine were divided into groups according to their diagnoses, and an averaged absolute percent dose difference for each group was calculated. The percentage dose difference for each treatment target was obtained as the relative difference between the Gamma Knife Check dose and the dose from the tissue maximum ratio algorithm (TMR 10) from the GammaPlan software version 10 at the reference point. For treatment plans with imaging skull definition, results obtained from the Gamma Knife Check software using the measurement-based skull definition method are used for comparison. The collected dose difference data were also analyzed in terms of the distance from the treatment target to the skull, the number of treatment shots used for the target, and the gamma angles of the treatment shots. The averaged percent dose differences between the Gamma Knife Check software and the GammaPlan treatment planning system are 0.3%, 0.89%, 1.24%, 1.09%, 0.83%, 0.55%, 0.33%, and 1.49% for the trigeminal neuralgia, acoustic neuroma, arteriovenous malformation (AVM), meningioma, pituitary adenoma, glioma, functional disorders, and metastasis cases on the Perfexion unit. The corresponding averaged percent dose differences for the 4C unit are 0.33%, 1.2%, 2.78% 1.99%, 1.4%, 1.92%, 0.62%, and 1.51%, respectively. The dose difference is, in general, larger for treatment targets in the peripheral regions of the skull owing to the difference in the numerical methods used for skull shape simulation in the GammaPlan and the Gamma Knife Check software. Larger than 5% dose differences were observed on both machines for certain targets close to patient skull surface and for certain targets in the lower half of the brain on the Perfexion, especially when shots with 70 and/or 110 gamma angles are used. Out of the 1065 treatment targets studied, a 5% cutoff criterion cannot always be met for the dose differences between the studied versions of the Gamma Knife Check software and the planning system for 40 treatment targets.

Leksell Gamma Knife treatment for pilocytic astrocytomas: long-term results.

OBJECTIVE The purpose of this study was to evaluate long-term treatment results, radiation-related toxicity, and prognostic factors for the progression-free survival (PFS) of patients with pilocytic astrocytomas treated by means of stereotactic radiosurgery with a Leksell Gamma Knife. METHODS A total of 25 patients with pilocytic astrocytomas underwent Gamma Knife surgery during the period 1992-2002. The median target volume was 2700 mm(3) (range 205-25,000 mm(3)). The 18 patients treated with 5 daily fractions received a median minimum target dose of 25 Gy. Doses for the 2 patients treated with 10 fractions over 5 days (2 fractions delivered on the same day at least 6 hours apart) were 23 and 28 Gy. For the 5 patients treated with a single fraction, the minimum target dose ranged from 13 to 20 Gy (median 16 Gy). RESULTS Complete regression occurred in 10 patients (40%) and partial regression in 10 patients (40%). The 10-year overall survival rate was 96% and the 10-year PFS rate was 80%. Target volume appeared to be a significant prognostic factor for PFS (p = 0.037). Temporary Grade 3 toxicity appeared in 2 patients (8%), and these patients were treated with corticosteroids for 2 months. Permanent Grade 4 toxicity appeared in 2 patients (8%) and was associated with neurocognitive dysfunction. In these 2 individuals, the neurocognitive dysfunction was also felt to be in part the result of the additional therapeutic interventions (4 in one case and 6 in the other) required to achieve durable control of their tumors. CONCLUSIONS Radiosurgery represents an alternative treatment modality for small residual or recurrent volumes of pilocytic astrocytomas and provides long-term local control. Target volume appears to be the most important factor affecting PFS.

The emergence of regional immigrant concentrations in USA and Australia: a spatial relatedness approach.

This paper examines the patterns of the US and Australian immigration geography and the process of regional population diversification and the emergence of new immigrant concentrations at the regional level. It presents a new approach in the context of human migration studies, focusing on spatial relatedness between individual foreign-born groups as revealed from the analysis of their joint spatial concentrations. The approach employs a simple assumption that the more frequently the members of two population groups concentrate in the same locations the higher is the probability that these two groups can be related. Based on detailed data on the spatial distribution of foreign-born groups in US counties (2000-2010) and Australian postal areas (2006-2011) we firstly quantify the spatial relatedness between all pairs of foreign-born groups and model the aggregate patterns of US and Australian immigration systems conceptualized as the undirected networks of foreign-born groups linked by their spatial relatedness. Secondly, adopting a more dynamic perspective, we assume that immigrant groups with higher spatial relatedness to those groups already concentrated in a region are also more likely to settle in this region in future. As the ultimate goal of the paper, we examine the power of spatial relatedness measures in projecting the emergence of new immigrant concentrations in the US and Australian regions. The results corroborate that the spatial relatedness measures can serve as useful instruments in the analysis of the patterns of population structure and prediction of regional population change. More generally, this paper demonstrates that information contained in spatial patterns (relatedness in space) of population composition has yet to be fully utilized in population forecasting.

Leksell Gamma Knife radiosurgery of the jugulotympanic glomus tumor: long-term results.

OBJECT: Glomus tumors usually display indolent behavior, and the effectiveness of radiation in stopping their growth can be assessed after long-term follow-up. Currently only midterm results of radiosurgery are available, so the authors included patients treated by Gamma Knife at least 10 years ago in this study to obtain a perspective of long-term results. METHODS: During the period from 1992 to 2003, the Gamma Knife was used to treat 46 patients with glomus tumors. The age of the patients ranged from 21 to 79 years (median 56 years). Gamma Knife radiosurgery was the primary treatment in 17 patients (37%). Open surgery preceded radiosurgery in 46% of cases, embolization in 17%, and fractionated radiotherapy in 4%. The volume of the tumor ranged from 0.2 to 24.3 cm(3) (median 3.6 cm(3)). The minimal dose to the tumor margin ranged between 10 and 30 Gy (median 20 Gy). RESULTS: One patient was lost for follow-up after radiosurgery. Clinical follow-up was available in 45 patients and 44 patients were followed with MRI in a follow-up period that ranged from 12 to 217 months (median 118 months). Neurological deficits improved in 19 (42%) of 45 patients and deteriorated in 2 patients (4%). Tumor size decreased in 34 (77%) of 44 patients with imaging follow-up, while an increase in volume was observed in 1 patient (2%) 182 months after radiosurgery and Gamma Knife treatment was repeated. One patient underwent another Gamma Knife treatment for secondary induced meningioma close to the glomus tumor 98 months after initial radiosurgical treatment. Seven patients died 22-96 months after radiosurgery (median 48 months), all for unrelated reasons. CONCLUSIONS: Radiosurgery has proved to be a safe treatment with a low morbidity rate and a reliable long-term antiproliferative effect.

Standardization of terminology in stereotactic radiosurgery: Report from the Standardization Committee of the International Leksell Gamma Knife Society: special topic.

OBJECT: This report has been prepared to ensure more uniform reporting of Gamma Knife radiosurgery treatment parameters by identifying areas of controversy, confusion, or imprecision in terminology and recommending standards. METHODS: Several working group discussions supplemented by clarification via email allowed the elaboration of a series of provisional recommendations. These were also discussed in open session at the 16th International Leksell Gamma Knife Society Meeting in Sydney, Australia, in March 2012 and approved subject to certain revisions and the performance of an Internet vote for approval from the whole Society. This ballot was undertaken in September 2012. RESULTS: The recommendations in relation to volumes are that Gross Target Volume (GTV) should replace Target Volume (TV); Prescription Isodose Volume (PIV) should generally be used; the term Treated Target Volume (TTV) should replace TVPIV, GTV in PIV, and so forth; and the Volume of Accepted Tolerance Dose (VATD) should be used in place of irradiated volume. For dose prescription and measurement, the prescription dose should be supplemented by the Absorbed Dose, or DV% (for example, D95%), the maximum and minimum dose should be related to a specific tissue volume (for example, D2% or preferably D1 mm3), and the median dose (D50%) should be recorded routinely. The Integral Dose becomes the Total Absorbed Energy (TAE). In the assessment of planning quality, the use of the Target Coverage Ratio (TTV/ GTV), Paddick Conformity Index (PCI = TTV2/[GTV · PIV]), New Conformity Index (NCI = [GTV · PIV]/TTV2), Selectivity Index (TTV/PIV), Homogeneity Index (HI = [D2% ­D98%]/D50%), and Gradient Index (GI = PIV0.5/PIV) are reemphasized. In relation to the dose to Organs at Risk (OARs), the emphasis is on dose volume recording of the VATD or the dose/volume limit (for example, V10) in most cases, with the additional use of a Maximum Dose to a small volume (such as 1 mm3) and/or a Point Dose and Mean Point Dose in certain circumstances, particularly when referring to serial organs. The recommendations were accepted by the International Leksell Gamma Knife Society by a vote of 92% to 8%. CONCLUSIONS: An agreed-upon and uniform terminology and subsequent standardization of certain methods and procedures will advance the clinical science of stereotactic radiosurgery.