Film dosimetry using radiochromic EBT film in combination with a flatbed charge coupled device scanner is a useful method both for two-dimensional verification of intensity-modulated radiation treatment plans and for general quality assurance of treatment planning systems and linear accelerators. Unfortunately, the response over the scanner area is nonuniform, and when not corrected for, this results in a systematic error in the measured dose which is both dose and position dependent. In this study a novel method for background correction is presented. The method is based on the subtraction of a correction matrix, a matrix that is based on scans of films that are irradiated to nine dose levels in the range 0.08-2.93 Gy. Because the response of the film is dependent on the film's orientation with respect to the scanner, correction matrices for both landscape oriented and portrait oriented scans were made. In addition to the background correction method, a full dose uncertainty analysis of the film dosimetry procedure was performed. This analysis takes into account the fit uncertainty of the calibration curve, the variation in response for different film sheets, the nonuniformity after background correction, and the noise in the scanned films. The film analysis was performed for film pieces of size 16 x 16 cm, all with the same lot number, and all irradiations were done perpendicular onto the films. The results show that the 2-sigma dose uncertainty at 2 Gy is about 5% and 3.5% for landscape and portrait scans, respectively. The uncertainty gradually increases as the dose decreases, but at 1 Gy the 2-sigma dose uncertainty is still as good as 6% and 4% for landscape and portrait scans, respectively. The study shows that film dosimetry using GafChromic EBT film, an Epson Expression 1680 Professional scanner and a dedicated background correction technique gives precise and accurate results. For the purpose of dosimetric verification, the calculated dose distribution can be compared with the film-measured dose distribution using a dose constraint of 4% (relative to the measured dose) for doses between 1 and 3 Gy. At lower doses, the dose constraint must be relaxed.

Liposomal drug delivery appears to improve the antitumor effect and reduce toxicity compared with the free drug. The therapeutic index may be improved further by combining cytotoxic drugs and radiotherapy. Successful therapy requires that the cytotoxic agents reach the tumor cells. Therefore, we studied tumor growth and the microdistribution of liposomal doxorubicin (Caelyx) with and without additional ionizing radiation in human osteosarcoma xenografts in athymic mice. Caelyx was injected i.v. 1 day before single or fractionated radiotherapy. Both chemoirradiation regimens induced significant tumor growth delays and worked synergistically. Confocal laser scanning microscopy showed that intact liposomes were located in close proximity to endothelial cells, and the distribution of released doxorubicin was heterogeneous. Before radiotherapy, hardly any doxorubicin was localized in the central parts of the tumor. Radiotherapy increased the tumor uptake of doxorubicin by a factor of two to four, with drug being redistributed farther from the vessels in the tumor periphery and located around vessels in the central parts of the tumor. Colocalization of doxorubicin and hypoxic cells showed no distribution of drug into hypoxic areas. Dynamic contrastenhanced magnetic resonance imaging (MRI) 1 day before the injection of Caelyx and 2 days after treatment start showed that the combined treatment reduced the vascular volume and the vascular transfer rate of the MRI tracer. The results show that chemoirradiation with Caelyx induces synergistic treatment effects. Improved intratumoral drug uptake and distribution are responsible to some extent for the enhanced antitumor effect.

VMAT plans were more robust on average than conventional 3DCRT plans for DIBH when localization errors were taken into consideration. The combination of robust VMAT planning and DIBH generally improves the homogeneity and target doses.

Background and purpose . The aim of this study was to report on early effects of contemporary radiotherapy (RT) on healthrelated quality of life (HRQOL) and explore treatment-related contributors to the development of fatigue during RT in breast cancer (BC) patients. Material and methods . Consecutive BC patients (n ϭ 248) referred for postoperative RT at St. Olavs University Hospital in Trondheim, Norway were enrolled from February 2007 to October 2008. Clinical-and treatment data were recorded, and HRQOL were assessed before starting (baseline) and immediately after ending RT using the " EORTC QLQ-C30 " and the breast module " EORTC QLQ-BR23 " . Change scores from baseline were calculated. Predictors of increased fatigue during RT were explored with multiple regression analysis adjusted for relevant confounders. Results. The global QOL-and all functional scales remained stable, except for " future perspective " which improved signifi cantly during RT. Breast symptoms and fatigue increased signifi cantly during RT. Groups with elevated baseline fatigue remained more stable during RT than those with lower levels at baseline. The body volume receiving 40 Gy or more (V40) was a signifi cant predictor of increased fatigue during RT adjusted for chemotherapy, comorbidity and age (p ϭ 0.035). Conclusion . Contemporary RT has limited early effects on HRQOL. V40 is a signifi cant predictor of RT-related fatigue.Multimodal treatment has become standard management of most breast cancer (BC) patients [1]. Where multiple treatment modalities are involved, the contribution of each to quality of life and symptoms is diffi cult to quantify [2]. The impact of BC treatment on health-related quality of life (HRQOL) has broadly been reported in relation to surgery techniques [3] and systemic therapies [4]. Improvements of radiotherapy (RT) techniques with more individual treatment plans (contemporary RT) should indicate less adverse effects and impact on HRQOL, but these assumptions have not been documented sufficiently [2,3,5,6]. Limitations of previous studies involve lack of baseline measures [7,8], small study samples [6,9] or older trials with incomparable RT-techniques to current practice [5,10].Fatigue is one of the most frequent and debilitating side effects of BC treatment with adverse effects on quality of life [6,11 -16]. The etiologies of fatigue are multi-factorial and poorly understood and the relative contributions of the various treatment modalities remain unclear [14,17,18]. The association between the severity of fatigue and RT-variables (like dose or dose-volume) has been investigated [13,15], but hampered by limited samples (n ϭ 41 and n ϭ 52). To our knowledge no studies have tested specifi c hypotheses concerning RT-related contributors to fatigue developed during RT.Prospective longitudinal study designs are generally preferred when exploring associations and predictors of post-RT fatigue [11], and baseline-values of fatigue have commonly been adjusted for in regression models [11,14]. However, incl...

The build-up and depth-dose characteristics of a conventional "6 MV" beam can be maintained when changing to a flattening-filter-free modality by increasing the incident electron energy from 6.45 MeV to 8.0 MeV. This will at the same time reduce the out-of-field dose for regions up to 20 cm from the central axis by 10%-30% compared to the original FF situation.