The present study reports myeloablative total body irradiation (TBI) on an isocentrically mounted linac by laying the patient on the floor and management of abutting radiation fields and partial shielding of lungs. Dosimetrical efficacy of this novel technique was evaluated.

In this retrospective study, dosimetrical parameters from TBI plans on whole-body CT scans of 46 patients were analysed. The prescribed dose to TBI was 12 Gy in six fractions delivered over a period of 3 days for myeloablative conditioning. TrueBeam STx platform Linac (Varian Medical Systems Inc., Palo Alto, CA, USA) was used to deliver opposing fields. Radiation fields were abutted to form a single large field using an arithmetic formula at source-to-skin-distance of 210 cm.

Discrepancies in dose calculated by treatment planning system were within 1·6% accuracy, and dose profile at the junction of abutting radiation fields was reproduced within 3·0% accuracy. The real treatment time for each patient was ~30 minutes/fraction. Monitor unit was weighted for multiple sub-fields to achieve dose homogeneity within 5·0% throughout the whole body, and the mean dose to lung was ≤10 Gy.

Our abutting radiation field technique for myeloablative TBI is feasible in any existing linac bunker. ‘Island-blocking’ is feasible in this technique using multi-leaf collimator. This technique is cost-effective as it does not require any costly equipment than the readily available equipment in any radiotherapy facility. In general, TBI requires laborious planning procedures and spacious linac bunkers; this novel technique has the potential to change previously held notions.

To identify predictors of recovery in children with uncomplicated severe acute malnutrition (SAM).

This is a secondary data analysis from an individual randomised controlled trial, where children with uncomplicated SAM were randomised to three feeding regimens, namely ready-to-use therapeutic food (RUTF) sourced from Compact India, locally prepared RUTF or augmented home-prepared foods, under two age strata (6–17 months and 18–59 months) for 16 weeks or until recovery. Three sets of predictors that could influence recovery, namely child, family and nutritional predictors, were analysed.

Rural and urban slum areas of three states of India, namely Rajasthan, Delhi and Tamil Nadu.

In total, 906 children (age: 6–59 months) were analysed to estimate the adjusted hazard ratio (AHR) using the Cox proportional hazard ratio model to identify various predictors.

Being a female child (AHR: 1·269 (1·016, 1·584)), better employment status of the child’s father (AHR: 1·53 (1·197, 1·95)) and residence in a rental house (AHR: 1·485 (1·137, 1·94)) increased the chances of recovery. No hospitalisation (AHR: 1·778 (1·055, 2·997)), no fever, (AHR: 2·748 (2·161, 3·494)) and ≤ 2 episodes of diarrhoea (AHR: 1·579 (1·035, 2·412)) during the treatment phase; availability of community-based peer support to mothers for feeding (AHR: 1·61 (1·237, 2·097)) and a better weight-for-height Z-score (WHZ) at enrolment (AHR: 1·811 (1·297, 2·529)) predicted higher chances of recovery from SAM.

The probability of recovery increases in children with better WHZ and with the initiation of treatment for acute illnesses to avoid hospitalisation, availability of peer support and better employment status of the father.

Radiation therapy has historically used margins for target volume to ensure dosimetric planning criteria. The size of margin for a given treatment site is still uncertain particularly for moving targets along with set-up variations leading to a fuzziness of target volume. In this study, we have estimated the dosimetric benefit of normal structures using biological-based optimal margins. The treatment margins are derived by knowledge-based fuzzy logic technique which is considering the radiotherapy uncertainties in treatment planning.

All treatment plans were performed using stepped increments of asymmetric margins to estimate prostate radiobiological indices such as tumour control probability (TCP) and normal tissue complication probability (NTCP). An absolute NTCP of 5% was considered to be the maximum acceptable value while TCP of 85% was considered to be the minimal acceptable limit for each volumetric modulated arc therapy (VMAT) plan of localised prostate cancer radiotherapy. Results were used to formulate rules and membership functions for Mamdani-type fuzzy inference system (FIS). In implementing the rules for the fuzzy system for ΔNTCP values above 10%, the PTV margin was not permitted to exceed 5 mm to avoid rectal complications due to margin selection. The new margins were applied in VMAT planning of prostate cancer for standard displacement errors. The dosimetric results of normal tissue predictors were estimated such as organ mean doses, rectum V60 (volume receiving 60 Gy), bladder V65 (volume receiving 65 Gy) and other clinically significant dose–volume indicators and compared with VMAT plans using current margin formulations.

Dosimetric results compared well to the results obtained by current techniques. Good agreement was obtained between proposed fuzzy model margins and currently used margins in lower error magnitude, but significant results were observed at higher error magnitude when organ toxicity concerned without compromising the target volumes.

The new margins may be helpful to estimate possible outcomes of normal tissue complications and thus may improve complication free survival particularly when organ motion errors are inevitable, case by case.

Previous studies showed that replacing conventional flattened beams (FF) with flattening filter-free (FFF) beams improves the therapeutic ratio in lung stereotactic body radiation therapy (SBRT), but these findings could have been impacted by dose calculation uncertainties caused by the heterogeneity of the thoracic anatomy and by respiratory motion, which were particularly high for target coverage. In this study, we minimised such uncertainties by calculating doses using high-spatial-resolution Monte Carlo and four-dimensional computed tomography (4DCT) images. We aimed to evaluate more reliably the benefits of using FFF beams for lung SBRT.

For a cohort of 15 patients with early-stage lung cancer that we investigated in a previous treatment planning study, we recalculated dose distributions with Monte Carlo using 4DCT images. This included 15 FF and 15 FFF treatment plans.

Compared to Monte Carlo, the treatment planning system (TPS) over-predicted doses in low-dose regions of the planning target volume (PTV). For most patients, replacing FF beams with FFF beams improved target coverage, tumour control, and uncomplicated tumour control probabilities.

Monte Carlo tends to reveal deficiencies in target coverage compared to coverage predicted by the TPS. Our data support previously reported benefits of using FFF beams for lung SBRT.

It is unknown whether patient disengagement from early intervention services for psychosis is as prevalent in low- and middle-income countries (LMICs) like India, as it is in high-income countries (HICs). Addressing this gap, we studied two first-episode psychosis programs in Montreal, Canada and Chennai, India. We hypothesized lower service disengagement among patients and higher engagement among families in Chennai, and that family engagement would mediate cross-site differences in patient disengagement.

Sites were compared on their 2-year patient disengagement and family engagement rates conducting time-to-event analyses and independent samples t tests on monthly contact data. Along with site and family involvement, Cox proportional hazards regression included known predictors of patient disengagement (e.g. gender).

The study included data about 333 patients (165 in Montreal, 168 in Chennai) and their family members (156 in Montreal, 168 in Chennai). More Montreal patients (19%) disengaged before 24 months than Chennai patients (1%), χ2(1, N = 333) = 28.87, p < 0.001. Chennai families had more contact with clinicians throughout treatment (Cohen's d = −1.28). Family contact significantly predicted patient disengagement in Montreal (HR = 0.87, 95% CI 0.81–0.93). Unlike in Chennai, family contact declined over time in Montreal, with clinicians perceiving such contact as not necessary (Cohen's d = 1.73).

This is the first investigation of early psychosis service engagement across a HIC and an LMIC. Patient and family engagement was strikingly higher in Chennai. Maintaining family contact may benefit patient engagement, irrespective of context. Findings also suggest that differential service utilization may underpin cross-cultural variations in psychosis outcomes.

The aim of this study was to investigate the extent to which lung stereotactic body radiotherapy (SBRT) treatment plans can be improved by replacing conventional flattening filter (FF) beams with flattening filter-free (FFF) beams.

We selected 15 patients who had received SBRT with conventional 6-MV photon beams for early-stage lung cancer. We imported the patients’ treatment plans into the Eclipse 13·6 treatment planning system, in which we configured the AAA dose calculation model using representative beam data for a TrueBeam accelerator operated in 6-MV FFF mode. We then created new treatment plans by replacing the conventional FF beams in the original plans with FFF beams.

The FFF plans had better target coverage than the original FF plans did. For the planning target volume, FFF plans significantly improved the D98, D95, D90, homogeneity index and uncomplicated tumour control probability. In most cases, the doses to organs at risk were lower in FFF plans. FFF plans significantly reduced the mean lung dose, V10, V20, V30, and normal tissue complication probability for the total lung and improved the dosimetric indices for the ipsilateral lung. For most patients, FFF beams achieved lower maximum doses to the oesophagus, heart and the spinal cord, and a lower chest wall V30.

Compared with FF beams, FFF beams achieved lower doses to organs at risk, especially the lung, without compromising tumour coverage; in fact, FFF beams improved coverage in most cases. Thus, replacing FF beams with FFF beams can achieve a better therapeutic ratio.

Purported superior outcomes for treatment of psychosis in low- and middle-income (LMICs) compared with high-income (HICs) countries have not been examined in the context of early intervention services (EIS).

To compare 2-year clinical outcomes in first-episode psychosis (FEP) treated in EIS in Chennai (LMIC) and Montreal (HIC) using a similar EIS treatment protocol and to identify factors associated with any outcome differences.

Patients with FEP treated in EIS in Chennai (n = 168) and Montreal (n = 165) were compared on change in level of symptoms and rate and duration of positive and negative symptom remission over a 2-year period. Repeated-measures analysis of variance, and logistic and linear regression analyses were conducted.

Four patients died in Chennai compared with none in Montreal. Family support was higher for Chennai patients (F = 14.05, d.f. = 1, P < 0.001, ƞp2 = 0.061) and increased over time at both sites (F = 7.0, d.f. = 1.915, P < 0.001, ƞp2 = 0.03). Negative symptom outcomes were significantly better in Chennai for level of symptoms (time × site interaction F = 7.36, d.f. = 1.49, P = 0.002, ƞp2 = 0.03), duration of remission (mean 16.1 v. 9.78 months, t = −7.35, d.f. = 331, P < 0.001, Cohen's d = 0.80) and the proportion of patients in remission (81.5% v. 60.3%, χ2 = 16.12, d.f. = 1, P < 0.001). The site differences in outcome remained robust after adjusting for inter-site differences in other characteristics. Early remission and family support facilitated better outcome on negative symptoms. No significant differences were observed in positive symptom outcomes.

Patients with FEP treated in EIS in LMIC contexts are likely to show better outcome on negative symptoms compared with those in HIC contexts. Early remission and family support may benefit patients across both contexts.