The comparative study of the plan quality between volumetric modulated arc therapy (VMAT) and 3D conformal therapy (3DCRT) for the treatment of selected representative childhood neoplasms was performed.

During the year 2013, 44 children with neoplasms were irradiated using VMAT. The 3DCRT plans were created retrospectively and compared with the VMAT plans for four tumour locations. The conformity parameters, dose volume histograms for target volume and organs at risk, number of monitor units and time used to deliver the single fraction were evaluated and compared for each plan. Additionally, for patients with brain tumour the comparison of different arcs configuration was made.

VMAT modality presented the superiority over older conformal methods with regard to the improvement in the dose conformity and normal tissue sparing. The noncoplanar arcs arrangement was beneficial in the decrease of high-dose volume and the protection of the organs at risk located oppositely to the target volume.

VMAT could be preferred technique for treating childhood neoplasms, especially when the complex-shaped target volume is localised close to the critical structures. The noncoplanar arcs arrangement could be the method of choice in the reirradiated patients and in these with laterally located brain tumours.

To describe the relationship between specific levels of nitrite intake from cured meat consumption during pregnancy and the relative risk of paediatric brain tumours in the offspring.

Exposure data were previously collected for a population-based case–control study of paediatric brain tumours; data on nitrite content were obtained by a comprehensive literature review of surveys of residual nitrite content in cured meats published in the USA and Canada. The level of nitrite intake for each mother was predicted by year of pregnancy based on survey results. Dose–response was evaluated both categorically and continuously using polynomial and quadratic spline regression.

The US west coast: Los Angeles County, the San Francisco–Oakland Bay Area and the Seattle–Puget Sound area.

There were 540 cases diagnosed between 1984 and 1990 at ages varying from 0 to 19 years, and 801 controls frequency-matched by geographic area, age and birth year.

In general, survey results suggest a trend of decreasing nitrite levels in cured meats over time. We observed a moderate increase in brain tumour risk in the offspring of mothers with relatively low levels of nitrite consumption from cured meats during pregnancy, and a two- to three-fold risk increase in offspring of mothers who consumed 3 mg day−1 nitrite from cured meats (about 125 g day−1 of cured meat consumption throughout the pregnancy).

A substantial risk of paediatric brain tumour appears to be associated with relatively high levels of maternal cured meat consumption during pregnancy. A more scientifically valid approach than a literature review to estimate nitrite intake from cured meats and data from a large group of highly exposed subjects would be useful in determining potentially harmful levels.