31– 33 Calibration against a standard block was performed daily, while precision monitoring against a standard lumbar spine bone mineral density phantom was undertaken weekly.
C-reactive protein was measured by a high-sensitivity turbidimetry assay (Dako, Glostrup, Denmark), assessed daily for precision (Allin et al, 2009).
Tumours were measured daily using precision callipers, and were excised once a volume of between 1 and 2 ml was reached (for experiments evaluating the impact of volume, tumours between 0.5 and 3.5 ml were used).
YKL-40 was measured in duplicates by a commercial two-site sandwich-type enzyme-linked immunosorbent assay (Quidel Corporation, San Diego, CA, USA) (Harvey et al, 1998; Johansen et al, 2009a), assessed daily for precision.
The assays were assessed daily for precision by using internal controls for each assay (coefficient of variation was 3% at a level of 1.7 mg/L for the nephelometry assay and 6% at a level of 2.1 mg/L for the turbidimetry assay) and monthly for accuracy through a Scandinavian quality control program.
A Vitalograph Compact II instrument was used, which was calibrated at least twice daily using a precision syringe.
However, compared with mean daily temperature, the precision of the estimates for maximum temperatures were lower and the AIC values were larger for minimum temperatures (data not shown).
Values of body weight, food and water consumption were established by weighing the animal, the food pellets and water bottle daily using a precision balance (PR 2003 Delta Range, Mettler-Toledo AG, Greifensee, Switzerland) especially designed to weigh moving animals.
Since a major goal of IMRT is to limit dose to normal tissue structures that often reside very close to tumour targets, daily set-up precision takes on much greater significance.
