Radiotherapy-induced damage to non-cancerous gastrointestinal mucosa has effects on secretory and absorptive functions and can interfere with normal gastrointestinal physiology. Nutrient absorption and digestion may be compromised. Dietary manipulation is an attractive option with sound rationale for intervention. The aim of this review was to synthesise published evidence for the use of elemental formulae, low or modified fat diets, fibre, lactose restriction and probiotics, prebiotics and synbiotics to protect the bowel from gastrointestinal side effects during long-course, radical pelvic radiotherapy. Thirty original studies (recruiting n 3197 patients) were identified comprising twenty-four randomised controlled trials, four cohort studies and two comparator trials. Endpoints varied and included symptom scales (Inflammatory Bowel Disease Questionnaire, Common Technology Criteria for Adverse Events, Radiation Therapy Oncology Group) and Bristol Stool Scale. Dietary and supplement interventions were employed with many studies using a combination of interventions. Evidence from RCT was weak for elemental, low or modified fat and low-lactose interventions and modestly positive for the manipulation of fibre during radiotherapy. Evidence for probiotics as prophylactic interventional agents was more promising with a number of trials reporting positive results but strength and strains of interventions vary, as do methodologies and endpoints making it difficult to arrive at firm conclusions with several studies lacking statistical power. This consolidated review concludes that there is insufficient high-grade evidence to recommend nutritional intervention during pelvic radiotherapy. Total replacement of diet with elemental formula could be effective in severe toxicity but this is unproven. Probiotics offer promise but cannot be introduced into clinical practice without rigorous safety analysis, not least in immunocompromised patients.

Context: Setup error significantly affects the accuracy of treatment and outcome in high precision radiotherapy.

Aims: To determine total, systematic, random error and clinical target volume (CTV) to planning target volume (PTV) margin with alpha cradle (VL) and ray cast (RC) immobilisation in abdominopelvic region.

Methods and material: Setup error was compared by using digitally reconstructed radiograph (DRR) as reference image with electronic portal image (EPI) taken during the treatment. Statistical analysis used: The total errors in mediolateral (ML), craniocaudal (CC) and anteroposterior (AP) directions were compared by t-test. For systematic and random errors variance ratio test (F-statistics) was used. Margins were calculated using International Commission of Radiation Units (ICRU), Stroom’s and van Herk’s formula.

Results: A total number of 306 portal images were analysed with 144 images in RC group and 162 images in VL group. For VL, in ML, CC, AP directions systematic errors were, in cm, (0.45, 0.29, 0.41), random errors (0.48, 0.32, 0.58), CTV to PTV margins (1.24, 0.80, 1.25), respectively. For RC, systematic errors were (0.25, 0.37, 0.80), random error (0.46, 0.80, 0.33), CTV to PTV margins (0.82, 1.30, 1.08), respectively. The difference of random error in CC and AP directions were statistically significant.

Conclusions: Geometric errors and CTV to PTV margins are different in different directions. For abdomen and pelvis in VL immobilisation, the margin ranged from 8 mm to 12.4 mm and for RC it was 8.2 mm to 13 mm. Therefore, a margin of 10 mm with online correction would be adequate.

Background and purpose. The objective of this study was to assess set-up reproducibility of pelvic treatments for obese patients in the prone position, with and without the use of an immobilisation shell.

Method and materials. The patients were treated using a posterior open field and opposed lateral wedged fields for 20 fractions over four weeks. Ten fractions were set-up using a pelvic shell and ten fractions without. The patients were randomised into two groups, whose initial set-up was either with or without a shell. Portal images were obtained on 14 treatment fractions (7 for each set-up) and compared against initial simulator images to assess movement. For each fraction when portal imaging was scheduled the treatment radiographers also assessed the ease at which the patient could be positioned. The aim was to determine the correlation between good visual positioning to surface marks and accurate location of bony landmarks in portal imaging.

Results. Early results from this study highlighted large random positioning errors in the superior/inferior plane when patients were positioned in the pelvic shell. The study was therefore abandoned at patient number four.

Conclusion. The use of the pelvic shell was found to increase positioning errors in the longitudinal (superior-inferior) direction. Reasons for this observation are discussed and modifications to the shell design suggested. The study also highlighted that ease of patient positioning using surface marks is not a good guide to positional accuracy and emphasises the importance of regular on-set verification.

Electronic portal imaging (EPI) has been used in the assessment of the accuracy of radiotherapy treatments in the pelvis. The daily reproducibility of any treatment is primarily dependent on the effectiveness of the set-up method. Treatments of radical planned volumes within the pelvis are subject to field placement errors (FPE) which could potentially compromise the successful outcome of radiotherapy treatment. Increasing use of shaped treatment fields to limit the dose delivered to surrounding normal tissues has prompted a more detailed examination of set-up methods.

Within the radiotherapy department at the Leicester Royal Infirmary it was noted that tattooed marks on the anterior or posterior and the lateral skin surface, marked at simulation, could not always be aligned for daily radiotherapy treatment.

An assessment of the relative merit of the anterior/posterior or the lateral tattoos in determining the isocentre position in the superior-inferior (cranio-caudal) plane is presented. This study showed that changes in the use of tattoo marks during set-up would have reduced the incidence of FPE >5 mm for a small sample group of patients. Implementation of changes in clinical practice, or research using a larger sample group is now needed to verify any improvement in accuracy using a modified treatment set-up technique.

Purpose: A randomized study to investigate the routine use of a simulator-based CT (Sim-CT) for planning purposes.

Materials and methods: 24 patients accepted for pelvic radiotherapy were randomized to receive either a Sim-CT or a DCT planning CT scan. The execution time was measured for different steps in both procedures. A questionnaire was developed to gain information about the psychological status and physical comfort.

Results: The set-up (of hardware, software and patient) took significantly longer for the Sim-CT procedure (p<0.05). An average of 5.7 min was found in comparison with 3.2 min for the DCT group. A similar result (p<0.0005) was observed for the scan time (resp. 15.9 versus 5.1 min). However the total time of the procedure (including patient preparation) was significantly lower (p<0.005) for the Sim-CT group (resp. 21.6 versus 31.7 min). Physical comfort score showed that some patients experienced more discomfort during the Sim-CT procedure than during DCT.

Conclusions: The scan acquisition time and set-up time of Sim-CT procedure was significantly higher than DCT however the total time was less for Sim-CT group. The overall reduction in time with Sim-CT is counterbalanced by increased patient discomfort.