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Background and purpose: Intensity modulated radiotherapy (IMRT) allows the delivery of higher and more homogeneous radiation dose to head and neck tumours. This study aims to determine the safety of dose-escalated chemo-IMRT for larynx preservation in locally advanced head and neck cancer. Methods: Patients with T2–4, N1–3, M0 squamous cell carcinoma of the larynx or hypopharynx were treated with a simultaneous-boost IMRT. Two radiation dose levels (DL) were tested: In DL 1, 63 Gy/28F was delivered to primary tumour and involved nodes and 51.8 Gy/28F to elective nodes. In DL 2, the doses were 67.2 Gy/28F and 56 Gy/28F, respectively, representing a 9% dose escalation for the primary. All patients received 2 cycles of neoadjuvant cisplatin and 5-fluorouracil, and concomitant cisplatin. Acute (NCICTCv.2.0) and late toxicity (RTOG and modified LENTSOM) were collected. Results: Thirty patients were entered, 15 in each dose level. All patients completed the treatment schedule. In DL 1, the incidences of acute G3 toxicities were 27% (pain), 20% (radiation dermatitis), 0% (xerostomia) and 67% required gastrostomy tubes. For DL 2 the corresponding incidences were 40%, 20%, 7%, and 87%. G3 dysphagia and pain persisted longer in DL 2. With regard to mucositis, a prolonged healing time for DL 2 was found, with prevalence of G2 of 58% in week 10. No acute grade 4 toxicity was observed. At 6 months, 1 patient in DL 2 had G3 late toxicity (dysphagia). No dose limiting toxicity was found. Complete response rates were 80% in DL 1, and 87% in DL 2. Conclusion: Moderately accelerated chemo-IMRT is safe and feasible with good compliance and acceptable acute toxicity. Dose escalation was possible without a significant difference in acute toxicity. Longer follow-up is required to determine the incidence of late radiation toxicities, and tumour control rates. c 2007 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 85 (2007) 36–41.

In this study, we aimed to create a comprehensive register of UK research radiographers (RRs), identify perceived training needs and make recommendations for the forward planning of the RR community in 2007 and 2008. Radiotherapy departments in England were sent an Academic Clinical Oncology and Radiobiology Research Network (ACORRN) questionnaire on RR establishment, demographics, role descriptions, research responsibilities, funding, time allocations, research skills and barriers to research. ACORRN received 85 replies from 51 departments of which just 5 RRs had a 100% research role. 70 radiographers participated in research at some level. 13 departments did not have any RRs. The RR role was defined as both developmental and specialist in nature by 43% of respondents; the remainder had a more diverse role. The National Health Service Trusts were responsible for funding 40% of RRs; the rest were fully or part-funded by national or local cancer networks, charity appeals and industry. 61% of RRs did not have dedicated academic time despite 93% being required to teach or support others. Critical barriers reported in conducting research were time, funding and supporting others In conclusion, the ACORRN RR Working Party makes the following recommendations for the future development of the community: the role of research should be viewed as an integral feature, at least one RR should be employed per radiotherapy department, the RR community must work together, dedicated research time is required, along with stable funding, RRs require more training, RRs need more support to accomplish the diversity of roles.

Purpose: This study assesses the accuracy of NOMOS B-mode acquisition and targeting system (BAT) compared with computed tomography (CT) in localizing the prostate. Methods and Materials: Twenty-six patients were CT scanned, and the prostate was localized by 3 observers using the BAT system. The BAT couch shift measurements were compared with the CT localization. Six of the patients had gold markers present in the prostate, and the prostate movement determined by BAT was compared with the movement determined by the gold markers. Results: Using the BAT system, the 3 observers determined the prostate position to be a mean of 1-5 mm over all directions with respect to the CT. The proportion of readings with a difference >3 mm between the observers was in the range of 25% to 44%. The prostate movement based on gold markers was an average of 3-5 mm different from that measured by BAT. The literature assessing the accuracy and reproducibility on BAT is summarized and compared with our findings. Conclusions: We have found that there are systematic differences between the BAT-defined prostate position compared with that estimated on CT using gold grain marker seeds.

Patients receiving radical radiotherapy to the prostate are requested to maintain a full bladder to displace the dome of the bladder and small bowel from the target volume. This study investigated patients' ability to consistently maintain a full bladder throughout planning and treatment before (Study 1) and after (Study 2) the introduction of a patient information sheet.Bladder volumes were measured on 41 patients at CT scanning, simulation and once weekly during treatment using a portable ultrasound device, BladderScan BVI 3000. Patients were asked their assessment of bladder fullness, time since last urination and the volume of fluid drank. A patient information sheet on bladder filling was then introduced and the study repeated on 25 patients (Study 2). The ultrasound bladder volumes measured at CT were compared to the CT scan data.There was a strong correlation between the ultrasound and CT bladder volumes r = 0.88 (P0.01). There was a significant decrease between the volume at CT (mean 362 ml, SD 229 ml) and treatment (mean 251 ml, SD 171 ml) in Study 1 (P = 0.002). In Study 2 the mean volume at CT was 286 ml (SD 164 ml) compared to a mean of 312 ml (SD 196 ml) during treatment. The measured volume correlated with patient self-assessment (r = 0.47, P0.01). The median volume drank by patients in Study 2 was 350 ml (range 50-825 ml) compared to 450 ml (range 75-1500 ml) in Study 1.Our initial results showed patients were unable to maintain a constant bladder volume during planning and treatment. Implementation of written bladder filling instructions was shown to improve bladder volume consistency.

Background and purpose Patients with non-small cell lung cancer (NSCLC) often have inhomogeneous lung perfusion. Radiotherapy planning computed tomography (CT) scans have been accurately co-registered with lung perfusion single photon emission computed tomography (SPECT) scans to design radiotherapy treatments which limit dose to healthy ‘perfused' lung. Patients and methods Patients with localised NSCLC had CT and SPECT scans accurately co-registered in the planning system. The SPECT images were used to define a volume of perfused ‘functioning' lung (FL). Inverse planning software was used to create 3D-conformal plans, the planning objective being either to minimise the dose to whole lungs (WL) or to minimise the dose to FL. Results Four plans were created for each of six patients. The mean difference in volume between WL and FL was 1011.7cm 3 (range 596.2–1581.1cm 3 ). One patient with bilateral upper lobe perfusion deficits had a 16% reduction in FLV 20 (the percentage volume of functioning lung receiving ≥20Gy). The remaining patients had inhomogeneous perfusion deficits such that inverse planning was not able to sufficiently optimise beam angles to avoid functioning lung. Conclusion SPECT perfusion images can be accurately co-registered with radiotherapy planning CT scans and may be helpful in creating treatment plans for patients with large perfusion deficits.

Background and purpose To investigate the feasibility and the advantages of a portal-imaging mode on a medical accelerator, consisting of a thin low-Z bremsstrahlung target and a thin Gd 2 O 2 S/film detector, for patient imaging. Patients and methods The international code of practice for high-energy photon dosimetry was used to calibrate dosimetry instruments for the imaging beam produced by 4.75MeV electrons hitting a 6mm thick aluminium target. Images of the head and neck of a humanoid phantom were taken with a mammography film system and the dose in the phantom was measured with TLDs calibrated for this beam. The first head and neck patient images are compared with conventional images (taken with the treatment beam on a film radiotherapy verification detector). Visibility of structures for six patients was evaluated. Results Images of the head and neck of a humanoid phantom, taken with both imaging systems showed that the contrast increased dramatically for the new system while the dose required to form an image was less than 10 −2 Gy. The patient images taken with the new and the conventional systems showed that air–tissue interfaces were better defined in the new system image. Anatomical structures, visible on both films, are clearer with the new system. Additionally, bony structures, such as vertebrae, were clearly visible only with the new system. The system under evaluation was significantly better for all features in lateral images and most features in anterior images. Conclusions This pilot study of the new portal imaging system showed the image quality is significantly improved.

Aims : As the trend towards more conformal treatment continues, the accuracy of treatment delivery becomes more important. Conventionally, treatment set-up for prostate cancer patients is verified in relation to the bony anatomy. However, there can be prostate movement independent of bony anatomy. This study tested the feasibility of using Beam cath ® to enable online correction of treatment set-up in relation to the prostate position, and to assess inter-fraction and intra-fraction prostate movement. Materials and methods : Beam cath ® is a urethral catheter containing radio-opaque markers, which can be seen on electronic portal imaging, enabling verification of prostate rather than bony anatomy position. The Beam cath ® was used for planning and treatment of a boost phase of 10Gy in 5 fractions, delivered before the conventional conformal plan of 60Gy in 30 fractions. Patients were scanned by computed tomgography (CT), with and without the catheter, and a radio-opaque marker in the catheter was used as the isocentre of the boost phase to enable accurate and rapid pre-treatment isocentre adjustment. The set-up errors between the Beam Cath ® and bony images were compared to identify the magnitude of prostate movement, independent of bony anatomy. Post-treatment portal images were taken to assess intra-fraction prostate movement. Results : Of 29 patients approached to take part in the study, 18 patients gave informed consent, but only five completed the intended 5 fractions of the boost phase using Beam cath ® . Pre- and post-treatment portal images were obtained for a total of 29 fractions in six patients. Inter-fraction prostate movement, independent of bony anatomy, was identified. The mean movements were 0.2mm (standard deviation [SD] 1.2mm), 2.9mm (SD 3.1mm) and 0.7mm (SD 2.3mm) in the right–left (RL), cranio-caudal (CC) and anterior–posterior (AP) direction, respectively. The mean intra-fraction movement was 0.2mm (SD 1.2mm), 2.9mm (SD 3.1mm) and 0.7mm (SD 2.3mm) in the RL, CC and AP direction, respectively. Conclusion : Although independent prostate movement was identified, the use of Beam cath ® was poorly tolerated. Alternative methods of identifying and correcting for prostate movement should be investigated.

We studied the rate of response to palliative external beam radiation therapy (20 Gy/5 or 30 Gy/10 fractions) to the base of skull in 32 prostate cancer patients with cranial nerve dysfunction. Sixteen patients (50%; 95% CI, 34-66%) had a useful response to therapy. The median survival post-therapy was 3 months.

Background and purpose : Two systems have been developed for treating patients with locally advanced prostate cancer using intensity-modulated radiotherapy (IMRT): one using dynamic multi-leaf collimator delivery and the other using step-and-shoot. This paper describes the clinical implementation of these two techniques, and presents results from the first 14 patients treated in a clinical setting (nine dynamic, five step-and-shoot). Patients and methods : Dynamic treatments were planned using Corvus, and step-and-shoot using Helax-TMS; all were delivered using Elekta accelerators. Prior to the first clinical treatments, validation measurements were carried out for each system, including measurements for a complete IMRT treatment. The reproducibility of dynamic delivery and the characteristics of the accelerator for low-monitor-unit (MU) deliveries were also assessed. An extensive quality assurance (QA) program was performed for each of the patients. Additionally, timing measurements were carried out to assess the practicalities of the technique. Results : The planning objectives were met in most cases. Absolute doses for complete IMRT treatments were within 2%, on average, with dose distributions generally showing agreement within 3% or 3 mm. Beam modulation measurements made throughout each patient's treatment indicated that both delivery methods were reproducible. The dynamic plans required an average of 765MU per beam, with a treatment delivery time of 14 min; corresponding results for step-and-shoot plans were 105MU and 10 min. Conclusions : Two IMRT techniques for this group of patients have been successfully implemented in the clinic. The more complex dynamic treatments showed no advantages over the step-and-shoot approach. QA results have shown accurate and reproducible delivery for both techniques, giving increased confidence in the techniques and allowing a reduction in the QA program.

This paper describes the implementation of intensity modulated radiotherapy (IMRT) in a radiotherapy department. When preparing to set-up an IMRT programme, it is important to review departmental protocols with regard to immobilization, CT planning, treatment planning and verification. Any additional quality assurance steps also need to be fully understood. A new IMRT programme is most likely to be successful if it builds on established clinical experience with three-dimensional conformal radiotherapy (CRT). Training of radiographers, clinicians and physicists is critical, and both team-work and communication are vital to ensure a smooth transition from 3DCRT to IMRT delivery in the clinic.

The development of intensity modulated radiotherapy (IMRT) has allowed the delivery of concave dose distributions. Planning studies have demonstrated the potential clinical benefit of IMRT in the treatment of the prostate and pelvic nodes in patients with advanced prostate cancer. As a consequence, IMRT was clinically implemented in the Royal Marsden NHS Trust in September 2000, using Elekta Sli series linear accelerators and NOMOS Corvus v3.0 planning system. As a relatively new treatment procedure in the United Kingdom, the clinical implementation involved developing appropriate quality assurance and verification procedures as well as training staff. This paper describes the practicalities of implementing IMRT into the routine workload of the radiotherapy department.

Purpose : Accurate anatomical delineation of the gross tumour volume (GTV) is crucial for effective radiotherapy (RT) treatment of prostate cancers. Although reference to pelvic magnetic resonance (MR) for improved delineation of the prostate is a regular practice in some clinics, MR has not replaced CT due to its geometrical distortions and lack of electron-density information. The possibility and practicality of using MR only for RT treatment planning were studied. Materials and methods: The addition of electron-density information to MR images for conformal radiotherapy (CRT) planning of the prostate was quantified by comparing dose distributions created on the homogeneous density- and bulk-density assigned images to original CT for four patients. To quantify the MR geometrical distortions measurements of a phantom imaged in CT (Siemens Somatom Plus 4) and FLASH 3D T1-weighted MR (1.5 T whole body Siemens Magnetom Vision) were compared. Dose statistics from CRT treatment plans made on CT and MR for five patient data were compared to determine if MR-only treatment plans can be made. Results: The differences between dose-plans on bulk-density assigned images when compared to CT were less than 2% when water and bone values were assigned. Dose differences greater than 2% were observed when images of homogeneous-density assignment were compared to the CT. Phantom measurements showed that the distortions in the FLASH 3D T1-weighted MR averaged 2 mm in the volume of interest for prostate RT planning. For the CT and MR prostate planning study, doses delivered to the planning target volume (PTV) in CT and MR were always inside a 93–107% dose range normalised to the isocentre. Also, the doses to the organs-at-risk in the MR images were similar to the doses delivered to the volumes in the registered CT image when the organ volumes between the two images were similar. Conclusions: Negligible differences were observed in dose distribution between CRT plans using bone+water CT number bulk-assigned image and original CT. Also, the MR distortions were reduced to negligible amounts using large bandwidth MR sequence for prostate CRT planning. MR treatment planning was demonstrated using a large bandwidth sequence and bulk-assigned images. The development of higher quality, low distortion MR sequence will allow regular practice of this technique.

283 Background: Muscle invasive bladder cancer (MIBC) incidence increases with age, with many patients (pts) unfit for radical therapy. We aimed to demonstrate feasibility of delivery & acceptable rates of hypofractionated RT toxicity using image guided adaptive techniques for these pts in a multicentre trial. Methods: Pts with T2-T4aN0M0 MIBC had 36 Gray (Gy) in 6 fractions (fr) over 6 weeks & were randomised (1:1) to standard (SP) or adaptive planning (AP). For AP 3 RT plans (small, medium, large) were generated with preRT cone beam (CB) CT used to select best fitting ‘plan of the day’ at each fr. A QA programme aided standardised CBCT image interpretation. The SP group had RT with 1 plan. The aim was to exclude ≥30% grade ≥3 (≥G3) acute (to 3 months (m)) non-genitourinary (GU) toxicity for AP in pts with no MIBC death by 3m (p0=0.7 p1=0.9 α=0.05 β=0.2). Secondary endpoints included 36Gy/6fr acute toxicity in pts who had ≥1 RT fr & proportion of AP fr using small/large plan. Adverse events (AEs) were assessed (CTCAE v4) weekly on RT, 4 weeks & 3m post RT. Blind independent review assessed relatedness of non-GU AEs to RT. Results: Between Apr 2014 & Aug 2016 65 pts were randomised (SP (n=32) AP (n=33)) from 12 UK sites. Median age was 85yrs; 68% male; 92% transitional cell MIBC; 99% grade 3; 25% clinical stage T3 & 6% T4. 58 pts are evaluable to date, ≥G3 acute non-GU adverse reactions (AR) were reported in 2/30 (7%; 90% CI: 1%–20%) AP (G3 hyperkalemia & hyponatremia; G3 diarrhea & dehydration) & 3/28 (11%; 90% CI: 3% –25%) SP pts (G3 fatigue; G3 hyperkalemia, weight loss & anorexia; G3 diarrhoea). 24/65 (37%; 90% CI: 27%-48%) pts who had ≥1 RT fr had ≥G3 acute AEs including G4 hyponatremia (2 AP pts), G5 pneumonia (1 SP, 1 AP), G5 sepsis (1 AP) & G5 renal failure (1 SP) (all G4/5 unrelated to RT). 7/65 pts received 25% fr adapted has potential for benefit. Comparative randomised studies are needed to quantify benefits of AP over SP. Clinical trial information: 18815596.

Purpose The purpose of this study was to establish reproducible guidelines for delineating the clinical target volume (CTV) of the pelvic lymph nodes (LN) by combining the freehand Royal Marsden Hospital (RMH) and Radiation Therapy Oncology Group (RTOG) vascular expansion techniques. Methods and Materials Seven patients with prostate cancer underwent standard planning computed tomography scanning. Four different CTVs (RMH, RTOG, modified RTOG, and Prostate and pelvIs Versus prOsTate Alone treatment for Locally advanced prostate cancer [PIVOTAL] trial) were created for each patient, and 6 different bowel expansion margins (BEM) were created to assess bowel avoidance by the CTV. The resulting CTVs were compared visually and by using Jaccard conformity indices. The volume of overlap between bowel and planning target volume (PTV) was measured to aid selection of an appropriate BEM to enable maximal LN yet minimal normal tissue coverage. Results In total, 84 nodal contours were evaluated. LN coverage was similar in all groups, with all of the vascular-expansion techniques (RTOG, modified RTOG, and PIVOTAL), resulting in larger CTVs than that of the RMH technique (mean volumes: 287.3 cm3, 326.7 cm3, 310.3 cm3, and 256.7 cm3, respectively). Mean volumes of bowel within the modified RTOG PTV were 19.5 cm3 (with 0 mm BEM), 17.4 cm3 (1-mm BEM), 10.8 cm3 (2-mm BEM), 6.9 cm3 (3-mm BEM), 5.0 cm3 (4-mm BEM), and 1.4 cm3 (5-mm BEM) in comparison with an overlap of 9.2 cm3 seen using the RMH technique. Evaluation of conformity between LN-CTVs from each technique revealed similar volumes and coverage. Conclusions Vascular expansion techniques result in larger LN-CTVs than the freehand RMH technique. Because the RMH technique is supported by phase 1 and 2 trial safety data, we proposed modifications to the RTOG technique, including the addition of a 3-mm BEM, which resulted in LN-CTV coverage similar to that of the RMH technique, with reduction in bowel and planning target volume overlap. On the basis of these findings, recommended guidelines including a detailed pelvic LN contouring atlas have been produced and implemented in the PIVOTAL trial. The PIVOTAL trial was funded by Cancer Research United Kingdom(CRUK) 10/022, C5907/A11880, and C1491/A9895 and supported by National Institute for Health Research (NIHR) Clinical Research Network at participating sites. PIVOTAL was coordinated by CRUK-funded Clinical Trials and Statistics Unit, Institute of Cancer Research. We acknowledge NHS funding to the NIHR Biomedical Research Centre at the Royal Marsden NHS Foundation Trust and Institute of Cancer Research. Conflict of interest: none.

Purpose To compare mean heart and left anterior descending coronary artery (LAD) doses (NTDmean) and positional reproducibility in larger-breasted women receiving left breast radiotherapy using supine voluntary deep-inspiratory breath-hold (VBH) and free-breathing prone techniques. Materials and methods Following surgery for early breast cancer, patients with estimated breast volumes >750 cm3 underwent planning-CT scans in supine VBH and free-breathing prone positions. Radiotherapy treatment plans were prepared, and mean heart and LAD doses were calculated. Patients were randomised to receive one technique for fractions 1–7, before switching techniques for fractions 8–15 (40 Gy/15 fractions total). Daily electronic portal imaging and alternate-day cone-beam CT (CBCT) imaging were performed. The primary endpoint was the difference in mean LAD NTDmean between techniques. Population systematic (Σ) and random errors (σ) were estimated. Within-patient comparisons between techniques used Wilcoxon signed-rank tests. Results 34 patients were recruited, with complete dosimetric data available for 28. Mean heart and LAD NTDmean doses for VBH and prone treatments respectively were 0.4 and 0.7 (p < 0.001) and 2.9 and 7.8 (p < 0.001). Clip-based CBCT errors for VBH and prone respectively were ⩽3.0 mm and ⩽6.5 mm (Σ) and ⩽3.5 mm and ⩽5.4 mm (σ). Conclusions In larger-breasted women, supine VBH provided superior cardiac sparing and reproducibility than a free-breathing prone position.

Breath-holding techniques reduce the amount of radiation received by cardiac structures during tangential-field left breast radiotherapy. With these techniques, patients hold their breath while radiotherapy is delivered, pushing the heart down and away from the radiotherapy field. Despite clear dosimetric benefits, these techniques are not yet in widespread use. One reason for this is that commercially available solutions require specialist equipment, necessitating not only significant capital investment, but often also incurring ongoing costs such as a need for daily disposable mouthpieces. The voluntary breath-hold technique described here does not require any additional specialist equipment. All breath-holding techniques require a surrogate to monitor breath-hold consistency and whether breath-hold is maintained. Voluntary breath-hold uses the distance moved by the anterior and lateral reference marks (tattoos) away from the treatment room lasers in breath-hold to monitor consistency at CT-planning and treatment setup. Light fields are then used to monitor breath-hold consistency prior to and during radiotherapy delivery. © JoVE 2006-2014. All Rights Reserved.

OBJECTIVE: To effectively treat spine metastases, significant dose must be delivered to regions surrounding the spinal cord. We present a study comparing both step-and-shoot intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques to deliver a concomitant hypofractionated prescription dose to the diseased region and to the involved vertebrae. METHODS: Seven-field IMRT and a single arc VMAT were inversely planned on five (two cervical and three thoracic) spinal metastatic patients. Planning target volumes PTVm (macroscopic) and PTVe (elective involved vertebrae) and associated organs at risk were localised. Mean doses of 35 Gy to PTVm and 20 Gy to PTVe were prescribed in five fractions. Dose statistics, estimated delivery time and results of verification using Delta(4) (ScandiDos, Uppsala, Sweden) were compared. RESULTS: Deliverable plans were achieved with both IMRT and VMAT. The coverage to PTV was similar for both IMRT and VMAT (p=0.5) and the dose to the regions adjacent to the spinal cord was 1% higher with VMAT (p=0.04). The mean delivery time for VMAT was 3.5 min compared with 10.5 min for IMRT. Fewer monitor units were required to deliver IMRT than to deliver VMAT. The median (range) percentage of measured points with a γ-index

Aims Adaptive bladder radiotherapy, with plan of the day selection and plan library development based on individual filling patterns, has been previously modelled in patients receiving weekly hypofractionated treatment and improved geometric accuracy has been shown. The aim of this study was to assess the clinical implementation of the technique. Materials and methods Conformal plans (with small, intermediate and large planning target volumes) were developed for 25 patients. After pre-treatment cone-beam computed tomography, the optimal plan of the day was selected and delivered by two trained observers. Independent off-line plan selection was also carried out. Concordance between the on-line and off-line selections, frequency of plan usage, target coverage and normal tissue sparing were assessed. Results Plan selection concordance was 91%. Fifty-five per cent of fractions were delivered using small or large plans. The mean coverage of the clinical target volume by the 95% isodose was 99%. The mean reduction in the volume of normal tissue treated to 95% of the prescription dose was 219 cm 3 compared with the previous institutional standard approach. Conclusions Good concordance in plan selection is shown with clinical implementation of the adaptive strategy. Adequate target coverage was achieved with reduction in the volume of normal tissue irradiated to a high dose compared with the previous standard approach.

Objective: The purpose of this UK study was to evaluate interfraction reproducibility and body image score when using ultraviolet (UV) tattoos (not visible in ambient lighting) for external references during breast/chest wall radiotherapy and compare with conventional dark ink. Methods: In this non-blinded, single-centre, parallel group, randomized control trial, patients were allocated to receive either conventional dark ink or UV ink tattoos using computer-generated random blocks. Participant assignment was not masked. Systematic (∑) and random (σ) setup errors were determined using electronic portal images. Body image questionnaires were completed at pre-treatment, 1 month and 6 months to determine the impact of tattoo type on body image. The primary end point was to determine that UV tattoo random error (σsetup) was no less accurate than with conventional dark ink tattoos, i.e.

Objective: To evaluate three image acquisition presets for four-dimensional cone beam CT (CBCT) to identify an optimal preset for lung tumour image quality while minimizing dose and acquisition time. Methods: Nine patients undergoing radical conventionally fractionated radiotherapy for lung cancer had verification CBCTs acquired using three presets: Preset 1 on Day 1 (11 mGy dose, 240 s acquisition time), Preset 2 on Day 2 (9 mGy dose, 133 s acquisition time) and Preset 3 on Day 3 (9 mGy dose, 67 s acquisition time). The clarity of the tumour and other thoracic structures, and the acceptability of the match, were retrospectively graded by visual grading analysis (VGA). Logistic regression was used to identify the most appropriate preset and any factors that might influence the result. Results: Presets 1 and 2 met a clinical requirement of 75% of structures to be rated “Clear” or above and 75% of matches to be rated “Acceptable” or above. Clarity is significantly affected by preset, patient, observer and structure. Match acceptability is significantly affected by preset. Conclusion: The application of VGA in this initial study enabled a provisional selection of an optimal preset (Preset 2) to be made. Advances in knowledge: This was the first application of VGA to the investigation of presets for CBCT.

e633 Background: PS is a single use, self-insertable endorectal device designed as a daily image-guidance tool for prostate cancer RT. Rectal filling is a significant factor in prostate motion. We investigated the effect of PS on inter- and intrafraction prostate motion and its effect on anorectal dosimetry. Methods: 19 patients with localized prostate cancer were randomized to receive prostate RT with PS either in the 1st or 2nd half of treatment. For each patient two planning CT scans were acquired, without and with PS. Contours were delineated by one physician and planned with a forward multi-segment technique to a dose of 74Gy/37F. Dose surface histograms were created (VODCA). In all patients, 3 electromagnetic transponders (EM) were implanted into the prostate and daily online image-guided RT was performed using either cone-beam CT (Elekta) or Calypso–based localization with tracking. Interfraction systematic (Σ) and random (σ) errors were estimated for bone matching without and with PS using EM position as reference. CTV-PTV margins were generated using the Van Herk formula. In-house code was used to analyse intrafraction motion recorded by Calypso of the EM centroid in the RL, SI and AP planes for individual fractions. A 2-way ANOVA test (SPSS v22) was used to determine if PS had an effect on maximal intrafraction prostate displacement. Results: See Table. Conclusions: PS affects the dosimetric pattern to the anal canal and rectum and this may impact GI toxicity. Also, PS stabilizes the prostate, which could enable reduced planning margins. PS will now be assessed in post-prostatectomy RT within a randomized controlled trial, POPS. Clinical trial information: 11814. [Table: see text] [Table: see text] [Table: see text]

Prospectively compare patient setup accuracy and intrafraction motion of a standard 3-point thermoplastic mask with the Gill-Thomas-Cosman relocatable stereotactic frame, during fractionated cranial radiation therapy using the ExacTrac system (Brainlab AG Feldkirchen, Germany) for daily online correction.The number of fractions with all postcorrection and post-treatment errors2 mm was assessed in 21 patients undergoing fractionated stereotactic radiation therapy (13 frame setup, 8 mask setup) using daily online correction. Achievable patient setup accuracy and total intrafraction motion were evaluated. The relative contributions of movement during floor rotation and patient movement to intrafraction motion were calculated.With daily online correction, patient setup margins can be reduced from 1, 5, and 4 mm in the lateral, longitudinal, and vertical axes for mask setup and from 1-2, 2, and 1 mm, respectively, for frame setup to1 mm isotropically for either immobilization system. Intrafraction movement was small for frame setup (mean [SD], -0.3 [0.3], -1.1[0.4], and -0.2 [0.6] in lateral, longitudinal and vertical axes, respectively; maximum, -2.7 mm [longitudinal axis]), and mask-setup (mean [SD], -0.4 [0.5], -0.8 [0.7], and 0.0 [0.3], respectively; maximum, -2.0 mm [longitudinal axis]) and is mainly due to floor rotation. Postcorrection and post-treatment errors were all2 mm in 95% and 99% of fractions in the mask and frame, respectively, meeting the criteria for a 3-mm clinical target volume-planning target volume margin for either immobilization method.Daily online correction can compensate for less precise immobilization and permits stereotactic margins to be used for standard thermoplastic masks without the need for specialized mask systems.

Objectives: The aim of this article was to test a simple approach of using pixel density values from fluoroscopy images to enable gated radiotherapy. Methods: Anterior and lateral (LAT) from images were acquired from 18 patients referred for radical radiotherapy for non-small cell lung cancer for a period of 30–45 s. The amplitude of movement and the number of breathing cycles were determined in the right–left (RL) and superoinferior (SI) directions on the anterior images and the anteroposterior (AP) and SI directions on the lateral images. The breathing pattern was created by analysing the variation in a summation of pixel values within a defined area. The greatest and lowest 30% of pixel values were set as the duty cycle to represent inhale and exhale amplitude-based gating. Results: A median of eight breathing cycles was captured for each patient with a duration of 2.2–11.8 s per cycle. The mean (range) motion was 4.7mm (2.4–5.8 mm), 7.2mm (2.3–17.6 mm), 6.2mm (1.9–13.8 mm) and 4.8mm (2.4–11.3mm) in the RL, SI (AP), SI (LAT) and AP directions, respectively. A total of 10/14 anterior videos and 7/11 LAT videos had correlations between motion and breathing of .0.6. Margins of 5.5 mm, 6.8mm and 6.6mm in the RL, SI and AP directions, respectively, were determined to gate in exhale. The benefit of gating was greater when motion was .5 mm. Conclusion: The simple approach of using pixel density values from fluoroscopy images to distinguish inhale from exhale and enable gating was successfully applied in all patients. This technique may potentially provide an accurate surrogate for tumour position.

To assess feasibility and reproducibility of an Active Breathing Coordinator (ABC) used throughout radical radiotherapy for non-small-cell lung cancer, and compare lung dosimetric parameters between free-breathing and ABC plans.A total of 18 patients, recruited into an approved study, had free-breathing and ABC breath-hold treatment plans generated. Lung volume, the percentage volume of lung treated to a dose of ≥20 Gy (V(20)), and mean lung dose (MLD) were compared. Treatment (64 Gy in 32 fractions, 5 days/week) was delivered in breath-hold. Repeat breath-hold computed tomography scans were used to assess change in gross tumor volume (GTV) size and position. Setup error was also measured and potential GTV-planning target volume (PTV) margins calculated.Seventeen of 18 patients completed radiotherapy using ABC daily. Intrafraction tumor position was consistent, but interfraction variation had mean (range) values of 5.1 (0-25), 3.6 (0-9.7), and 3.5 (0-16.6) mm in the superoinferior (SI), right-left (RL), and anteroposterior (AP) directions, respectively. Tumor moved partially outside the PTV in 5 patients. Mean reduction in GTV from planning to end of treatment was 25% (p = 0.003). Potentially required PTV margins were 18.1, 11.9, and 11.9 mm in SI, RL, and AP directions. ABC reduced V(20) by 13% (p = 0.0001), V(13) by 12% (p = 0.001), and MLD by 13% (p0.001) compared with free-breathing; lung volume increased by 41% (p0.001).Clinically significant movements of GTV were seen during radiotherapy for non-small-cell lung cancer using ABC. Image guidance is recommended with ABC. The use of ABC can reduce dose volume parameters determining lung toxicity, and might allow for equitoxic radiotherapy dose escalation.

The median age of patients at the start of treatment was 70 years (range 37e85 years). Post-radiotherapy haemoptysis was reported in 3 patients (5.1%). No patient developed myelopathy. The commonest described toxicity was dysphagia, but only 3 (6.9%) developed grade 3 dysphagia. Median field size was 122.79 cm 2 (range 28e243 cm 2 ), consistent with the comparator where field size did not normally exceed 200 cm 2 . Conclusions: High dose palliative radiotherapy in Oxford University’s NHS Trust is safe and tolerable with no radiation induced myelopathy. The main toxicity of dysphagia is generally non-severe. The median survival of patients is comparable to the 9 month survival seen in the 13 fraction arm of the MRC Trial, indicating a genuine application to everyday radiotherapy practice.

Background and purpose This pilot study investigates whether an individualized fluid and fibre prescription combined with a constant treatment can improve rectal filling consistency during radiotherapy. Methods and materials Fibre, fluid intake and bowel function were assessed in 22 patients at a standard planning scan (SCT) and individualized dietary advice was prescribed to regularize bowel habit. Patients were requested to record frequency and type of bowel movements, fibre and fluid intake daily. Two subsequent CT scans were acquired at 7 (CCT1) and 10days (CCT2) after SCT at a similar time. Rectal volume and gas were measured planning CT's and ‘on treatment' cone beam CT scans. We hypothesised that the difference in volume between CCT1 and CCT2 would be less than the difference between SCT and CCT1. Results The mean (SD) change in volume between SCT to CCT1 and CCT1 to CCT2 was 5.68cm 3 (26.2) and −8.6cm 3 (40.1), respectively ( p =0.292). Of the 22 patients scanned 20 provided a complete record of dietary intake and bowel motion. The majority of patients either achieved or exceeded prescription. Change in rectal gas was the only correlation with change in rectal volume. Conclusion Patient self reporting of bowel motion, fibre, fluid intake was achievable but consistency of rectal filling was not improved. Improved understanding of the aetiology and management of rectal gas is indicated.

AIM: Pelvic irradiation in addition to prostate irradiation may improve outcome in locally advanced prostate cancer, but is associated with dose-limiting bowel toxicity. We report the preliminary results of a dose escalation study using intensity-modulated radiotherapy. MATERIALS AND METHODS: Eligible patients had high-risk (T3, Gleason > or =8 or prostate-specific antigen > or =20 ng/ml) or lymph node-positive disease. Intensity-modulated radiotherapy was inverse planned giving 70 Gy/35 fractions to the prostate and 50 Gy/55 Gy/60 Gy in sequential cohorts to the pelvis with a 5 Gy boost to positive lymph nodes. Acute and late toxicity were recorded with Radiation Therapy Oncology Group (RTOG) and Late Effects Normal Tissue - Subjective Objective Management LENT-SOM scales. Neoadjuvant androgen suppression was given for 3 years. This report concerns the 50 and 55 Gy cohorts. RESULTS: Seventy-nine men were recruited (25 to 50 Gy/54 to 55 Gy) with a median follow-up of 2 years. Patients were divided into two groups according to the total bowel volume outlined (median 450 cm(3)). Acute RTOG (> or =2) bowel toxicity was 40 and 50% for the 50 and 55 Gy groups and 38 and 51% for bowel volume or =450 cm(3), respectively, suggesting both volume and dose relationships for acute effects. Late RTOG diarrhoea > or =grade 2 was only seen with bowel volume > or =450 cm(3), but no dose effect was apparent (12%/50 Gy and 10%/55 Gy). LENT-SOM bowel > or =grade 2 toxicity occurred in 22%/50 Gy and 15%/55 Gy. Only one patient had grade 3 toxicity. A dose volume histogram analysis showed increased late RTOG diarrhoea > or =grade 2 with larger bowel volume irradiated, significant for BV40 >124 cm(3) (P=0.04), BV45 >71 cm(3) (P=0.03) and BV60 >2 cm(3) (P=0.01). CONCLUSIONS: Acute and late bowel toxicity was acceptably low using a pelvic dose of up to 55 Gy over 7 weeks. Both relate to total pelvic bowel volume and dose volume constraints have been defined.

The past decade has provided many technological advances in radiotherapy. The European Institute of Radiotherapy (EIR) was established by the European Society of Therapeutic Radiology and Oncology (ESTRO) to provide current consensus statement with evidence-based and pragmatic guidelines on topics of practical relevance for radiation oncology. This report focuses primarily on 3D CT-based in-room image guidance (3DCT-IGRT) systems. It will provide an overview and current standing of 3DCT-IGRT systems addressing the rationale, objectives, principles, applications, and process pathways, both clinical and technical for treatment delivery and quality assurance. These are reviewed for four categories of solutions; kV CT and kV CBCT (cone-beam CT) as well as MV CT and MV CBCT. It will also provide a framework and checklist to consider the capability and functionality of these systems as well as the resources needed for implementation. Two different but typical clinical cases (tonsillar and prostate cancer) using 3DCT-IGRT are illustrated with workflow processes via feedback questionnaires from several large clinical centres currently utilizing these systems. The feedback from these clinical centres demonstrates a wide variability based on local practices. This report whilst comprehensive is not exhaustive as this area of development remains a very active field for research and development. However, it should serve as a practical guide and framework for all professional groups within the field, focussed on clinicians, physicists and radiation therapy technologists interested in IGRT. (C) 2010 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 94 (2010) 129-144

INTRODUCTION: The prognosis from non-small cell lung cancer remains poor, even in those patients suitable for radical radiotherapy. The ability of radiotherapy to achieve local control is hampered by the sensitivity of normal structures to irradiation at the high tumour doses needed. This study aimed to look at the potential gain in tumour control probability from dose escalation facilitated by moderate deep inspiration breath-hold. METHOD: The data from 28 patients, recruited into two separate studies were used. These patients underwent planning with and without the use of moderate deep inspiration breath-hold with an active breathing control (ABC) device. Whilst maintaining the mean lung dose (MLD) at the level of the conventional plan, the ABC plan dose was theoretically escalated to a maximum of 84 Gy, constrained by usual normal tissue tolerances. Calculations were performed using data for both lungs and for the ipsilateral lung only. Resulting local progression-free survival at 30 months was calculated using a standard logistic model. RESULTS: The prescription dose could be escalated from 64 Gy to a mean of 73.7+/-6.5 Gy without margin reduction, which represents a statistically significant increase in tumour control probability from 0.15+/-0.01 to 0.29+/-0.11 (p

Background. Volumetric modulated arc therapy (VMAT) is a radiotherapy technique in which the gantry rotates while the beam is on. Gantry speed, multileaf collimator (MLC) leaf position and dose rate vary continuously during the irradiation. For optimum results, this type of treatment should be subject to image guidance. The application of VMAT and image guidance to the treatment of a lung cancer patient is described. Material and methods. In-house software AutoBeam was developed to facilitate treatment planning for VMAT beams. The algorithm consisted of a fluence optimisation using the iterative least-squares technique, a segmentation and then a direct-aperture optimisation. A dose of 50 Gy in 25 fractions was planned, using a single arc with 35 control points at 108 intervals. The resulting plan was transferred to a commercial treatment planning system for final calculation. The plan was verified using a 0.6 cm 3 ionisation chamber and film in a rectangular phantom. The patient was treated supine on a customised lung board and imaged daily with cone-beam CT for the first three days then weekly thereafter. Results. The VMAT plan provided slightly improved coverage of the planning target volume (PTV) and slightly lower volume of lung irradiated to 20 Gy (V20) than a three-field conformal plan (PTV minimum dose 85.0 Gy vs. 81.8 Gy and lung V20 31.5% vs. 34.8%). The difference between the measured and planned dose was 1.1% (measured dose lower) and 97.6% of the film passed a gamma test of 3% and 3 mm. The VMAT treatment required 90 s for delivery of a single fraction of 2 Gy instead of 180 s total treatment time for the conformal plan. Conclusion. VMAT provides a quality dose distribution with a short treatment time as shown in an example of a lung tumour. The technique should allow for more efficient delivery of high dose treatments, such as used for hypofractionated radiotherapy of small volume lung tumours, and the technique may also be used in conjunction with Active Breathing Control, where fewer breath holds will be required.

To evaluate the utility of intraprostatic markers in the treatment verification of prostate cancer radiotherapy. Specific aims were: to compare the effectiveness of offline correction protocols, either using gold markers or bony anatomy; to estimate the potential benefit of online correction protocol's using gold markers; to determine the presence and effect of intrafraction motion.Thirty patients with three gold markers inserted had pretreatment and posttreatment images acquired and were treated using an offline correction protocol and gold markers. Retrospectively, an offline protocol was applied using bony anatomy and an online protocol using gold markers.The systematic errors were reduced from 1.3, 1.9, and 2.5 mm to 1.1, 1.1, and 1.5 mm in the right-left (RL), superoinferior (SI), and anteroposterior (AP) directions, respectively, using the offline correction protocol and gold markers instead of bony anatomy. The subsequent decrease in margins was 1.7, 3.3, and 4 mm in the RL, SI, and AP directions, respectively. An offline correction protocol combined with an online correction protocol in the first four fractions reduced random errors further to 0.9, 1.1, and 1.0 mm in the RL, SI, and AP directions, respectively. A daily online protocol reduced all errors to1 mm. Intrafraction motion had greater impact on the effectiveness of the online protocol than the offline protocols.An offline protocol using gold markers is effective in reducing the systematic error. The value of online protocols is reduced by intrafraction motion.

Background The effectiveness of ABC has been traditionally measured as the reduction in internal margin (IM) within the planning target volume (PTV). Not to overestimate the benefit of ABC, the effect of patient movement during treatment also needs to be taken into account. We determined the IM and set-up error with ABC and the effect on physical lung parameters compared to standard margins used with free breathing. We also assessed interfraction oesophageal movement to determine a planning organ at risk volume (PRV). Materials and methods Two sequential studies were performed using ABC in NSCLC patients suitable for radical radiotherapy (RT). Twelve out of 14 patients in Study 1 had tumours visible fluoroscopically and had intrafraction tumour movement assessed with and without ABC. Sixteen patients were recruited to Study 2 and had interfraction tumour movement measured using ABC in a moderate deep inspiration breath-hold, of these 7 patients also had interfraction oesophageal movement recorded. Interfraction movement was assessed by CT scan prior to and in the middle and final week of RT. Displacement of the tumour centre of mass and oesophageal borders relative to the first scan provided a measure of movement. Set-up error was measured in 9 patients treated with an in-house lung board adapted for the ABC device. Combining movement and set-up errors determined PTV and PRV margins with ABC. The effect of ABC on mean lung dose (MLD), lung V 20 and V 13 was calculated. Results ABC in a moderate deep inspiration breath-hold was tolerated in 25 out of 30 patients (83%) in Study 1 and 2. The random contribution of periodic tumour motion was reduced by 90% in the y direction with ABC compared to free-breathing. The magnitude of motion reduction was less in the x and z direction. Combining the systematic and random set-up error in quadrature with the systematic and random intrafraction and interfraction tumour variations with ABC results in a PTV margin of 8.3mm in the x direction, 12.0mm in the y direction and 9.8mm in the z direction. There was a relative mean reduction in MLD, lung V 20 and V 13 of 25%, 21% and 18% with the ABC PTV compared to a free-breathing PTV. Oesophageal movement combined with set-up error resulted in an isotropic PRV of 4.7mm. Conclusions The reduction in PTV size with ABC resulted in an 18–25% relative reduction in physical lung parameters. PTV margin reduction has the potential to spare normal lung and allow dose-escalation if coupled with image-guided RT. The oesophageal PRV needs to be considered when irradiating central disease and is of increasing importance with altered RT fractionation and concomitant chemoradiation schedules. Further reductions in PTV and PRV may be possible if patient set-up error was minimised, confirming that attention to patient immobilisation is as important as attempts to control tumour motion.

Aims To quantify the inter-fractional variation in bladder volume and position during a course of bladder radiotherapy, and to assess the feasibility of reducing the planning target volume (PTV) internal margin using an empty bladder protocol. Materials and methods Weekly computed tomography scans were taken immediately after micturition on 15 patients undergoing radical radiotherapy for bladder cancer. Bladder volume and positional variation were compared by co-registration of the serial computed tomography scans with the initial planning scan and a single ‘full' scan at the onset of treatment for each patient. A PTV was generated on the initial planning scan using both our departmental standard of 1.5cm and a reduced 1cm isotropic internal margin around the target (whole bladder) and the relative proportion of the bladder breaching the PTV using both margins compared. Results The mean post void residual volume from the planning scan was 112cm 3 (standard deviation 42cm 3 ). The mean weekly variation in bladder volume relative to the planning volume was 0–12% (standard deviation 20–34%) with no observable trends over time. No statistically significant differences were seen in the proportion of bladder breaching the 1.5 and 1cm internal margin ( P =0.18). Regression analysis showed that it is possible to ensure complete coverage of the bladder with a 1cm margin, providing the volume did not exceed over 50% of the initial planning scan volume. Conclusion Using an empty bladder protocol and where on-line imaging is available it is feasible to reduce the internal margin of the PTV from 1.5 to 1cm, providing the volumes do not exceed >50% of the planning scan volume.

Background Delivering training to participating sites is an essential part of successful trial setup especially when new techniques, treatments or technologies are involved. RAIDER is a multicentre (> 30 NHS Trusts) phase II trial of complex radiotherapy for muscle invasive bladder cancer. The radiotherapy techniques were developed at a single UK NHS site and in addition to written materials ideally require demonstration using the relevant radiotherapy planning and imaging software, only available at the experienced site. Rather than arranging a series of visits from key participating site personnel (Principal Investigator (PI) and research radiographers), a virtual meeting plan was developed.

To investigate whether there was parity between treatment fields localized by radiographers and clinicians, by comparing geographical variations and hence determining the feasibility of a radiographer-led service.23 patients with metastatic spinal cord compression (MSCC) were prospectively sampled. Four radiographers not involved in the original planning performed localization on each patient. The 92 localizations that they determined were compared with the clinician-approved fields. Agreement was defined as ≤0.5 cm between field length, width and three isocentre co-ordinates. To be feasible, agreement was required in a minimum of 97% of the cases. The potential time saved with a radiographer-led approach was also recorded.Agreement between clinicians and radiographers was 97.8%. For all field parameters, the average differences were0.3 cm and were significantly different from the 0.5-cm median (p 0.0001) that would establish no agreement using Wilcoxon signed-rank test. The average (range) delay awaiting clinician approval was 54 min (4-141 min).Strong agreement between radiographer and clinician localizations was established. It was also highlighted that time could be saved in the patient's pathway by removing the need to wait for clinician approval. We believe this supports a radiographer-led service.This article is novel, as it is the first known comparison between clinicians and radiographers in the localization of MSCC radiotherapy. These data show the feasibility of introducing radiographer-led practice and a methodology that could be potentially transferred to investigate the localization parity for other treatment sites.

307 Background: Advances in IGART offer individualized solutions to improve target coverage and reduce normal tissue irradiation allowing opportunity to increase radiation tumour dose and spare normal bladder. Methods: A library of 3 IMRT plans were created (small, medium and large) from planning CT scans performed at 30 and 60 minutes; treating whole bladder to 52 Gy and tumour to 70 Gy in 32 fractions. Where normal tissue dose constraints were not met consideration was made to boosting tumour to lower dose (68 Gy-64 Gy). Cone beam CT (CBCT) imaging was performed prior to each fraction. Appropriate PTV was selected from the library for treatment delivery. Post treatment CBCT was acquired weekly in order to assess intra-fraction filling and coverage. Results: 22 patients have been planned using this technique. All have met tissue constraints for treatment to 70 Gy. 21 patients have completed radiotherapy, 18 completed treatment to 70 Gy; 1 patient was planned and treated to 68 Gy prior to dose escalation using this technique; 1 patient was treated to a total dose of 65.6 Gy because dose limiting toxicity occurred before dose escalation. 572 CBCTs have been evaluated. Treatment was delivered using small, medium, and large plans in 35%, 52%, and 13% cases respectively. Mean intra-fraction filling was 14 cm3 (SD 16.3, range 0.23-107.9). Mean time between pre- and post-CBCTs was 13 min (SD 2.1, range 9-18). Mean D 98% as assessed on post-radiotherapy CBCT was 98.7% (SD 1.78, range 89.9-100%). At median follow-up of 8 months (range 1-24 months), 18 patients remain alive and disease free. 2 superficial recurrences and 3 deaths from metastatic bladder cancer have occurred. No muscle invasive recurrences have occurred within this cohort. Using this technique one patient has experienced late toxicity (grade 3 cystitis) 5.3 months after radiotherapy (now resolved). Conclusions: IGART using IMRT to delivery a simultaneous integrated tumour boost is feasible with acceptable toxicity. Trial recruitment continues at 70 Gy and will be evaluated in a randomised trial (RAIDER). Clinical trial information: NCT01124682.

Purpose: To investigate the feasibility of fully automated detection of fiducial markers implanted into the prostate using portal images acquired with an electronic portal imaging device. Methods and Materials: We have made a direct comparison of 4 different methods (2 template matching-based methods, a method incorporating attenuation and constellation analyses and a cross correlation method) that have been published in the literature for the automatic detection of fiducial markers. The cross-correlation technique requires a-priory information from the portal images, therefore the technique is not fully automated for the first treatment fraction. Images of 7 patients implanted with gold fiducial markers (8 mm in length and 1 mm in diameter) were acquired before treatment (set-up images) and during treatment (movie images) using 1MU and 15MU per image respectively. Images included: 75 anterior (AP) and 69 lateral (LAT) set-up images and 51 AP and 83 LAT movie images. Using the different methods described in the literature, marker positions were automatically identified. Results: The method based upon cross correlation techniques gave the highest percentage detection success rate of 99% (AP) and 83% (LAT) set-up (1MU) images. The methods gave detection success rates of less than 91% (AP) and 42% (LAT) set-up images. The amount of a-priory information used and how it affects the way the techniques are implemented, is discussed. Conclusions: Fully automated marker detection in set-up images for the first treatment fraction is unachievable using these methods and that using cross-correlation is the best technique for automatic detection on subsequent radiotherapy treatment fractions.

We were pleased to read that other groups are exploring the feasibility of detailed self-recording of dietary intake in patients receiving long-course radiotherapy for prostate cancer. This has particular relevance in view of the continued interest in strategies to minimise rectal deformation and thus reduce prostate movement during radiotherapy planning and treatment. We completely agree with the authors’ finding that previous studies, which have explored dietary interventions (primarily anti-flatulent diets), have lacked information on patient compliance. Thus, in the one study, which failed to show a statistically significant difference in inter-fraction prostate motion, and in the two studies, in which worse outcomes were observed in terms of increased prostate displacement, it is impossible to know whether the outcomes result from a true lack of efficacy or indeed adverse effects of the diet alone. This uncertainty is compounded by the fact that only one of the studies used dietary change as the sole intervention. The others used a combination of laxatives and diet, and laxative diet and treatment scheduling. Further, only one study used a prospective comparator group with patients acting as their own controls.

The ability of intensity-modulated radiotherapy (IMRT) to sculpt the dose distribution closely around the tumour volume has the potential to have a major impact on radiotherapy clinical practice. However, dynamic IMRT treatment delivery differs from that of conventional treatment because of the constantly moving multileaf collimators (MLCs) and higher monitor units (MUs) required. The implementation of new technology can be affected by the users response. Radiographers' attitudes regarding technology and their perceptions of the clinical implementation of IMRT were explored using a qualitative study based on semi-structured interviews. 16 radiographers were interviewed and data was analysed using a framework analysis to identify themes and categories. The majority of radiographers (12/16) demonstrated positive attitudes regarding technology. The introduction of IMRT was seen to be stimulating and motivating. Negative aspects were associated with increased stress from learning new skills and the additional pressure of the increased workload. Although there were contradictory views regarding the effect of the increased use of technology on the patient-radiographer relationship, technological skills and patient care were not found to be mutually exclusive. Radiographers' perceptions regarding the clinical implementation of IMRT appeared to be influenced by their mainly positive attitudes regarding technology. With the current problems of recruitment and retention of radiographers, full exploitation of modern technology could be used to improve job satisfaction. However, careful integration is required to balance training needs with service demands.

Purpose To evaluate the precision of using digitally reconstructed radiographs (DRRs) of either 3 mm or 6 mm slice separation vs. using simulator images for the setup verification of patients receiving CT planned conformal radiotherapy to the prostate. To calculate the transfer error between CT and simulator. Methods and materials Twenty patients were CT scanned (3 mm slice spacing/width). DRRs were generated for both 3 mm (DRR 3) and 6 mm (DRR 6) separations. DRRs and a simulator image of an anterior and a lateral field were used as reference images. Five observers matched each of the reference images to treatment images using the Theraview "Target check" facility. It was assumed that poorer images would lead to a loss of precision of field placement estimations (FPE) between observers. The study was designed to detect a difference greater than 1.5 mm 2 in the precision of image placement. The transfer error was the mean difference in the setup error derived from the DRRs and the simulation films. Results The precision of evaluations for simulator films and 3 mm DRRs were similar. There was a trend for the DRR 6 mm to achieve less precise results which was greatest for craniocaudal examinations (variance: simulator 1.5 mm 2 , DRR6 2.8 mm 2 , p = 0.17), but this did not reach statistical significance. A range of transfer errors was identified, with standard deviations ranging from 1.7 to 4.2 mm. There was evidence of a significant systematic bias in anterior craniocaudal (1.3–1.9 mm, p p = 0.027). Conclusion The precision of setup evaluations using DRRs is similar to that achieved by using simulator fields when planning conformal prostate radiotherapy. The use of DRRs could reduce systematic errors introduced in the planning process.