A phase II trial of induction chemotherapy and chemo-IMRT for head and neck squamous cell cancers at risk of bilateral nodal spread: the application of a bilateral superficial lobe parotid-sparing IMRT technique and treatment outcomes.

PURPOSE: To determine the feasibility of induction chemotherapy and chemo-IMRT in head and neck squamous cell cancers at risk of bilateral nodal spread (midline tumours) and to evaluate whether bilateral superficial lobe parotid-sparing IMRT can reduce the incidence of ⩾G2 subjective xerostomia. METHODS: Patients with midline tumours were enrolled to a phase II trial to receive induction platinum/5-fluorouracil and concomitant platinum with combined superficial lobe parotid-sparing IMRT. The primary site and involved nodal levels received 65 Gy in 30 fractions (f) and at risk nodal levels, 54 Gy/30f. Incidence of ⩾G2 subjective xerostomia was defined as the primary endpoint. Secondary endpoints included incidences of acute and late toxicities and survival outcomes dependent on human papilloma virus (HPV) status. RESULTS: One hundred and twenty patients with midline cancers completed treatment between December 2005 and May 2010 with median follow-up of 50 months. Incidences of ⩾G2 acute toxicities were: dysphagia 75%; xerostomia 65%; mucositis 86%; pain 83%; and fatigue 64%. At 12 months, ⩾G2 subjective xerostomia was observed in 21% (17% in HPV +ve). Two-year loco-regional progression-free survival (PFS) was 90.7% (95% CI: 85.2-96.2). According to HPV status, there was a significant difference for 2-year loco-regional PFS, 76.8% (HPV-negative) vs 98.6% (HPV-positive), P=0.001. 2-year overall survival was 93% for HPV-positive compared with 52% for HPV-negative cases, P<0.001. CONCLUSIONS: Sequential chemotherapy/chemo-IMRT for midline tumours is feasible, with excellent survival outcomes. At 1 year, 21% experience ⩾G2 subjective xerostomia. Two-year survival outcomes differ significantly between HPV-positive and HPV-negative disease, suggesting development of different treatment schedules for the different disease entities.

European Society of Radiotherapy and Oncology (ESTRO) strategy 2024-2026: Growth and diversification in a rapidly changing world.

In 2019, the European Society of Radiotherapy and Oncology (ESTRO) published its 2030 Vision "Radiation Oncology, Optimal Health, For All, Together". However, in 2020, the global pandemic, coinciding with the Society's 40th anniversary, had long-term consequences on global behaviours and on the financial environment for scientific associations worldwide. In 2022, ESTRO conducted a survey among its members, revealing their strong appreciation for networking opportunities and the creation of high-quality interdisciplinary scientific content. In response to the survey findings and to address the evolving landscape following the COVID pandemic, ESTRO initiated a strategic review process to respond to, and refocus on, the opportunities and challenges ahead. This paper, marking a turning point in ESTRO's strategy for achieving its Vision 2030 in a post-pandemic era, describes the 2022-23 strategic review process, discussions, and consequent recommendations. The comprehensive strategic review process involved: (i) pre-meeting preparations with surveys and strategic documents; (ii) a carefully themed three-day retreat in Brussels incorporating a blend of plenary sessions, workshops focusing on ESTRO's role, value creation and capture, strategic objectives; and (iii) a post-retreat phase including qualitative analysis and development of action plans. The strategic review emphasized the need for adaptive tactics for scientific associations to remain current and productive in the face of changing global conditions. The development of key strategic goals for the years 2024-2026 focused on improving research impact, strengthening and diversifying ESTRO's educational offerings and fostering proactive and mutually beneficial partnerships. The Board approved these objectives, alongside prioritising digital innovation, financial sustainability, and community engagement for ESTRO's continued growth and development. In essence, ESTRO aims to advocate, empower, expand, and diversify its community, with the overarching goal of enhancing cancer care for patients in Europe, and beyond.

Development of a heterogeneous phantom to measure range in clinical proton therapy beams.

PURPOSE: In particle therapy, determination of range by measurement or calculation can be a significant source of uncertainty. This work investigates the development of a bespoke Range Length Phantom (RaLPh) to allow independent determination of proton range in tissue. This phantom is intended to be used as an audit device. METHOD: RaLPh was designed to be compact and allows different configurations of tissue substitute slabs, to facilitate measurement of range using radiochromic film. Fourteen RaLPh configurations were tested, using two types of proton fluence optimised water substitutes, two types of bone substitute, and one lung substitute slabs. These were designed to mimic different complex tissue interfaces. Experiments were performed using a 115 MeV mono-energetic scanning proton beam to investigate the proton range for each configuration. Validation of the measured film ranges was performed via Monte Carlo simulations and ionisation chamber measurements. The phantom was then assessed as an audit device, by comparing film measurements with Treatment Planning System (TPS) predicted ranges. RESULTS: Varying the phantom slab configurations allowed for measurable range differences, and the best combinations of heterogeneous material gave agreement between film and Monte Carlo on average within 0.2% and on average within 0.3% of ionisation chamber measurements. Results against the TPS suggest a material density override is currently required to enable the phantom to be an audit device. CONCLUSION: This study found that a heterogeneous phantom with radiochromic film can provide range verification as part of a dedicated audit for clinical proton therapy beams.

An end-to-end assessment on the accuracy of adaptive radiotherapy in an MR-linac.

PURPOSE: To develop and demonstrate an end-to-end assessment procedure for adaptive radiotherapy (ART) within an MR-guided system. METHODS AND MATERIALS: A 3D printed pelvic phantom was designed and constructed for use in this study. The phantom was put through the complete radiotherapy treatment chain, with planned internal changes made to model prostate translations and shape changes, allowing an investigation into three ART techniques commonly used. Absolute dosimetry measurements were made within the phantom using both gafchromic film and alanine. Comparisons between treatment planning system (TPS) calculations and measured dose values were made using the gamma evaluation with criteria of 3 mm/3% and 2 mm/2%. RESULTS: Gamma analysis evaluations for each type of treatment plan adaptation investigated showed a very high agreement with pass rates for each experiment ranging from 98.10% to 99.70% and 92.60% to 97.55%, for criteria of 3%/3 mm and 2%/2 mm respectively. These pass rates were consistent for both shape and position changes. Alanine measurements further supported the results, showing an average difference of 1.98% from the TPS. CONCLUSION: The end-to-end assessment procedure provided demanding challenges for treatment plan adaptations to demonstrate the capabilities and achieved high consistency in all findings.

Comparing Proton to Photon Radiotherapy Plans: UK Consensus Guidance for Reporting Under Uncertainty for Clinical Trials.

In the UK, the recent introduction of high-energy proton beam therapy into national clinical practice provides an opportunity for new clinical trials, particularly those comparing proton and photon treatments. However, comparing these different modalities can present many challenges. Although protons may confer an advantage in terms of reduced normal tissue dose, they can also be more sensitive to uncertainty. Uncertainty analysis is fundamental in ensuring that proton plans are both safe and effective in the event of unavoidable discrepancies, such as variations in patient setup and proton beam range. Methods of evaluating and mitigating the effect of these uncertainties can differ from those approaches established for photon therapy treatments, such as the use of expansion margins to assure safety. These differences should be considered when comparing protons and photons. An overview of the effect of uncertainties on proton plans is presented together with an introduction to some of the concepts and terms that should become familiar to those involved in proton therapy trials. This report aims to provide guidance for those engaged in UK clinical trials comparing protons and photons. This guidance is intended to take a pragmatic approach considering the tools that are available to practising centres and represents a consensus across multidisciplinary groups involved in proton therapy in the UK.

Radiotherapy Quality Assurance for the CHHiP Trial: Conventional Versus Hypofractionated High-Dose Intensity-Modulated Radiotherapy in Prostate Cancer.

AIMS: The CHHiP trial investigated the use of moderate hypofractionation for the treatment of localised prostate cancer using intensity-modulated radiotherapy (IMRT). A radiotherapy quality assurance programme was developed to assess compliance with treatment protocol and to audit treatment planning and dosimetry of IMRT. This paper considers the outcome and effectiveness of the programme. MATERIALS AND METHODS: Quality assurance exercises included a pre-trial process document and planning benchmark cases, prospective case reviews and a dosimetry site visit on-trial and a post-trial feedback questionnaire. RESULTS: In total, 41 centres completed the quality assurance programme (37 UK, four international) between 2005 and 2010. Centres used either forward-planned (field-in-field single phase) or inverse-planned IMRT (25 versus 17). For pre-trial quality assurance exercises, 7/41 (17%) centres had minor deviations in their radiotherapy processes; 45/82 (55%) benchmark plans had minor variations and 17/82 (21%) had major variations. One hundred prospective case reviews were completed for 38 centres. Seventy-one per cent required changes to clinical outlining pre-treatment (primarily prostate apex and base, seminal vesicles and penile bulb). Errors in treatment planning were reduced relative to pre-trial quality assurance results (49% minor and 6% major variations). Dosimetry audits were conducted for 32 centres. Ion chamber dose point measurements were within ±2.5% in the planning target volume and ±8% in the rectum. 28/36 films for combined fields passed gamma criterion 3%/3 mm and 11/15 of IMRT fluence film sets passed gamma criterion 4%/4 mm using a 98% tolerance. Post-trial feedback showed that trial participation was beneficial in evolving clinical practice and that the quality assurance programme helped some centres to implement and audit prostate IMRT. CONCLUSION: Overall, quality assurance results were satisfactory and the CHHiP quality assurance programme contributed to the success of the trial by auditing radiotherapy treatment planning and protocol compliance. Quality assurance supported the introduction of IMRT in UK centres, giving additional confidence and external review of IMRT where it was a newly adopted technique.

Target volume definition for head and neck intensity modulated radiotherapy: pre-clinical evaluation of PARSPORT trial guidelines.

AIMS: There is considerable controversy surrounding target volume definition for parotid-sparing intensity modulated radiotherapy (IMRT) for head and neck cancer. The aim of this study was to evaluate the dosimetric and radiobiological predictors of outcome anticipated by application of the detailed target volume definition guidelines agreed for the UK multicentre randomised controlled trial of parotid-sparing IMRT (PARSPORT). MATERIALS AND METHODS: Five patients eligible for the study were delineated using the trial guidelines. Following the protocol, plans were produced to treat these volumes with three-dimensional radiotherapy (control arm) and IMRT aimed to spare dose to the contralateral parotid gland (experimental arm). Dosimetric comparisons were made between plans, and normal tissue complication probability (NTCP) modelling for salivary glands was carried out. RESULTS: Doses delivered to the planning target volumes (PTV) were similar with each technique, although IMRT produced more homogeneous irradiation of the PTV. Mean doses to the contralateral parotid gland were 22.4+/-1.7 Gy with the IMRT plans vs 60.0+/-7.2 Gy with three-dimensional radiotherapy, P=0.0003. Calculated contralateral parotid gland NTCP values for grade 2 xerostomia were 20-22% for IMRT and 98-100% for three-dimensional radiotherapy (P<0.0001). CONCLUSION: Pre-clinical evaluation of the PARSPORT trial target volume definition guidelines provides theoretical support for a significant reduction in xerostomia rates. These data await confirmation from the clinical trial results.

Challenges in calculation of the gamma index in radiotherapy - Towards good practice.

The gamma index (γ) is one of the most commonly used metrics for the verification of complex modulated radiotherapy. The mathematical definition of the γ is computationally expensive and various techniques have been reported to speed up the calculation either by mathematically refining the γ or employing various computational techniques. These techniques can cause variation in output with different software implementations. The γ has traditionally been used to compare a 2D measured plane against a 2D or 3D dose distribution. Recently, software algorithm and hardware improvements have led to the possibility of using measured 2D data from commercial detector arrays to reconstruct a 3D-dose distribution and perform a volumetric comparison against the treatment planning system (TPS). A limitation in this approach is that commercial detector arrays have so far been limited by their spatial resolution which may affect the accuracy of the reconstructed 3D volume and subsequently the γ calculation. Additionally, 3D versus 3D γ comparison adds a layer of complication in the calculation of the γ given the increase in the number of calculation points and the result cannot be as easily interpreted in the same way as 2D comparison. This review summarises and highlights the computational challenges of the γ calculation and sheds light on some of these issues by means of a bespoke MATLAB software to demonstrate the impact of interpolation, γ search distance, resolution and 2D and 3D calculations. Finally, a recommendation is made on the minimum information that should be reported when publishing γ results.

A quantitative study of IMRT delivery effects in commercial planning systems for the case of oesophagus and prostate tumours.

This study focuses on understanding the impact of intensity-modulated radiotherapy (IMRT) delivery effects when applied to plans generated by commercial treatment-planning systems such as Pinnacle (ADAC Laboratories Inc.) and CadPlan/Helios (Varian Medical Systems). These commercial planning systems have had several version upgrades (with improvements in the optimization algorithm), but the IMRT delivery effects have not been incorporated into the optimization process. IMRT delivery effects include head-scatter fluence from IMRT fields, transmission through leaves and the effect of the rounded shape of the leaf ends. They are usually accounted for after optimization when leaf sequencing the "optimal" fluence profiles, to derive the delivered fluence profile. The study was divided into two main parts: (a) analysing the dose distribution within the planning-target volume (PTV), produced by each of the commercial treatment-planning systems, after the delivered fluence had been renormalized to deliver the correct dose to the PTV; and (b) studying the impact of the IMRT delivery technique on the surrounding critical organs such as the spinal cord, lungs, rectum, bladder etc. The study was performed for tumours of (i) the oesophagus and (ii) the prostate and pelvic nodes. An oesophagus case was planned with the Pinnacle planning system for IMRT delivery, via multiple-static fields (MSF) and compensators, using the Elekta SL25 with a multileaf collimator (MLC) component. A prostate and pelvic nodes IMRT plan was performed with the Cadplan/Helios system for a dynamic delivery (DMLC) using the Varian 120-leaf Millennium MLC. In these commercial planning systems, since IMRT delivery effects are not included into the optimization process, fluence renormalization is required such that the median delivered PTV dose equals the initial prescribed PTV dose. In preparing the optimum fluence profile for delivery, the PTV dose has been "smeared" by the IMRT delivery techniques. In the case of the oesophagus, the critical organ, spinal cord, received a greater dose than initially planned, due to the delivery effects. The increase in the spinal cord dose is of the order of 2-3 Gy. In the case of the prostate and pelvic nodes, the IMRT delivery effects led to an increase of approximately 2 Gy in the dose delivered to the secondary PTV, the pelvic nodes. In addition to this, the small bowel, rectum and bladder received an increased dose of the order of 2-3 Gy to 50% of their total volume. IMRT delivery techniques strongly influence the delivered dose distributions for the oesophagus and prostate/pelvic nodes tumour sites and these effects are not yet accounted for in the Pinnacle and the CadPlan/Helios planning systems. Currently, they must be taken into account during the optimization stage by altering the dose limits accepted during optimization so that the final (sequenced) dose is within the constraints.

Changes in Patterns of Intensity-modulated Radiotherapy Verification and Quality Assurance in the UK.

AIMS: Between 2012 and 2014 the number of patients treated in the UK with intensity-modulated radiotherapy (IMRT) techniques increased significantly. One reason for this was the radiotherapy innovation fund for the centres in England. Before the announcement of the fund, a survey of radiotherapy centres was carried out in 2012 which collected data on IMRT uptake, obstacles to implementation, equipment used, delivery techniques and verification methods. A repeat survey was carried out in 2014 to identify key changes to IMRT quality assurance and verification practices. MATERIALS AND METHODS: An online questionnaire was sent out to all 65 UK radiotherapy centres in the summer of 2012 and again in the summer of 2014. Questions covered background and equipment, machine tolerance and quality assurance, machine-based verification, software-based verification and future plans. RESULTS: There have been significant changes in the delivery techniques used for IMRT, with more than twice as many centres reporting the use of volumetric-modulated arc therapy techniques in 2014 compared with 2012. This has been combined with an increase in Monte Carlo-based algorithms in treatment planning systems. In 2012 all centres reported the need to carry out machine-based measurements for IMRT plan verification, dropping to 93% in 2014. Nineteen per cent of centres now report making only one measurement per month for prostate plans and 8% of breast plans never have physical measurements. Most centres use detector arrays for quality assurance measurement (86% in 2012 and 91% in 2014), but a significant number still use film and/or ionisation chambers (51% and 41%). In the analysis of these measurements there has been an increase in the use of tighter criteria. There has been a significant increase in the use of software for verification from 63% in 2012 to 95% in 2014. All centres reported that they needed further resources in order to efficiently achieve the quality assurance required for the number of patients planned to be treated in their centre. CONCLUSIONS: The increased numbers of patients being treated with IMRT has meant that there have been significant changes in the way that quality assurance is carried out. These have been mainly in the reduction of measurements and the increase in software-based verification. However, quality assurance is still a significant burden and still has an effect on the numbers of patients who can be treated with IMRT.

A controlled trial of light therapy for the treatment of pediatric seasonal affective disorder.

OBJECTIVE: To evaluate the efficacy of light therapy for the treatment of pediatric seasonal affective disorder (SAD). METHOD: 28 children (aged 7 to 17 years) at two geographically distinct sites were enrolled in a double-blind, placebo-controlled, crossover trial of bright-light treatment. Subjects initially entered a week-long baseline period during which they wore dark glasses for an hour a day. They were then randomly assigned to receive either active treatment (1 hour of bright-light therapy plus 2 hours of dawn simulation) or placebo (1 hour of clear goggles plus 5 minutes of low-intensity dawn simulation) for 1 week. The treatment phase was followed by a second dark-glasses phase lasting 1 to 2 weeks. After this phase, the children received the alternate treatment. Response was measured using the parent and child versions of the Structured Interview Guide for the Hamilton Depression Rating Scale, Seasonal Affective Disorders version (SIGH-SAD). RESULTS: Data were analyzed as change from baseline. SIGH-SAD-P total depression scores were significantly decreased from baseline during light therapy compared with placebo (one-way analysis of variance, rho = .009), and no differences were found between the placebo and control phases. Subscores of atypical and typical depression were also significantly decreased during the active treatment (rho = .004 and .028, respectively). A similar trend was noted with the SIGH-SAD-C, but this did not reach significance. At the end of the study, 78% of the parents questioned and 80% of the children questioned rated light therapy as the phase during which the child "felt best." CONCLUSION: Light therapy appears to be an effective treatment for pediatric SAD.

The reproducibility of depressive and hypomanic symptoms across repeated episodes in patients with rapid-cycling bipolar disorder.

The purpose of this study is to determine the stability of symptoms of hypomania and depression across repeated affective episodes in patients with rapid-cycling bipolar disorder. Nine patients had a total of 30 depressive episodes and 31 hypomanic episodes during the period of observation. Standardized observer ratings indicated that the three symptoms most consistently reported during depressive episodes were fatiguability, decreased work activities and hypersomnia. These results as well as those from the standardized observer ratings of hypomania indicate that depression in this population consists of a lethargic, hypoactive state while hypomania may be a heightened state of activation. The clinical and theoretical implications of these findings are discussed.

Agreement between face-to-face and telephone-administered mood ratings in patients with rapid cycling bipolar disorder.

We examined the reliability and level of agreement between the telephone and face-to-face administration of two mood-rating scales (HIGH-SAD and SIGH-SAD) in patients with rapid cycling bipolar disorder (RCBD). Two clinicians administered the HIGH-SAD and SIGH-SAD to 14 outpatients with RCBD. Patients received consecutive phone and face-to-face mood ratings in a randomized order. Using a paired t-test, no significant differences were found when comparing HIGH-SAD and SIGH-SAD scores administered face-to-face and over the phone. There was a high correlation between the face-to-face and phone administration of both scales as measured by intraclass correlation (r = 0.94 for SIGH-SAD; r = 0.85 for HIGH-SAD). Our results support the use of phone-administered mood ratings as a reliable and convenient method to monitor patients with RCBD.

Relationship between social rhythms and mood in patients with rapid cycling bipolar disorder.

Disruptions in the sleep-wake cycle frequently characterize affective illness and have led to a number of theories linking sleep-wake and/or circadian rhythm disturbance to affective illness. Recently, researchers have expanded these chronobiological theories to include the role of lifestyle regularity, or daily social rhythms. In this study, the Social Rhythm Metric (SRM) was used to explore the relationship between social rhythms and mood in patients with rapid cycling bipolar disorder and to compare the social rhythms of patients with those of healthy control subjects. Patients' SRM scores and activity level indices were significantly lower than those of control subjects. In addition, the timing of five, mostly morning, activities was phase delayed in patients compared to control subjects. Patients also demonstrated a phase delay in the timing of morning activities during depression compared to hypomania or euthymia. The phase changes in the timing of morning activities are consistent with other data implicating morning zeitgebers in the pathophysiology of rapid cycling bipolar disorder.

Implementation of IMRT in the radiotherapy department.

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.

Connective tissues: matrix composition and its relevance to physical therapy.

In the last 2 decades, the understanding of CT structure and function has increased enormously. It is now clear that the cells of the various CTs synthesize a variety of ECM components that act not only to underpin the specific biomechanical and functional properties of tissues, but also to regulate a variety of cellular functions. Importantly for the physical therapist, and as discussed above, CTs are responsive to changes in the mechanical environment, both naturally occurring and applied. The relative proportions of collagens and PGs largely determine the mechanical properties of CTs. The relationship between the fibril-forming collagens and PG concentration is reciprocal. Connective tissues designed to resist high tensile forces are high in collagen and low in total PG content (mostly dermatan sulphate PGs), whereas CTs subjected to compressive forces have a greater PG content (mostly chondroitin sulphate PGs). Hyaluronan has multiple roles and not only provides tissue hydration and facilitation of gliding and sliding movements but also forms an integral component of large PG aggregates in pressure-resisting tissues. The smaller glycoproteins help to stabilize and link collagens and PGs to the cell surface. The result is a complex interacting network of matrix molecules, which determines both the mechanical properties and the metabolic responses of tissues. Patients with CT problems affecting movement are frequently examined and treated by physical therapists. A knowledge of the CT matrix composition and its relationship to the biomechanical properties of these tissues, particularly the predictable responses to changing mechanical forces, offers an opportunity to provide a rational basis for treatments. The complexity of the interplay among the components, however, requires that further research be undertaken to determine more precisely the effects of treatments on the structure and function of CTs.

Gastric intramucosal pH: a noninvasive method for the indirect measurement of tissue oxygenation.

BACKGROUND: Monitoring the adequacy of tissue oxygenation is an important goal in the care of the critically ill patient. Global alterations in tissue oxygenation are inferred from changes in systemic oxygen transport (defined as the product of cardiac output and arterial oxygen content) and total oxygen consumption. These parameters, however, cannot measure the level of oxygenation of specific tissue beds, in particular those that are first affected by hypoxia, such as the gastrointestinal tract and the kidneys. DISCUSSION: Gastrointestinal tonometry is a new method for measuring the partial pressure of carbon dioxide of the gastrointestinal mucosa. This information can be used in conjunction with the arterial blood bicarbonate to calculate the pH of the mucosa. Mucosal acidosis correlates well with the onset of anaerobic metabolism in response to hypoxia or sepsis. This review discusses the basic principles of tonometry, the results of experimental and clinical studies, and the practical aspects related to the implementation and use of tonometers in patients in the critical care unit. CONCLUSION: Gastrointestinal tonometry is a relatively noninvasive device that appears capable of measuring metabolic changes produced by hypoxia. Because of the sensitive nature of the gastrointestinal mucosa, these changes often occur well in advance of other, more common, indices of hypoxia. The use of the tonometer may become a routine procedure in the overall monitoring of critically ill patients.

Spontaneous neonatal gastric perforation.

Sixteen cases of spontaneous neonatal gastric perforation seen between January 1969 and March 1979 are reported. There were 13 surgically treated patients and three autopsy cases. This study provides information relative to the incidence among black populations, an incidence 1 per 2,900 live births. The entity is at least four times more common in males than females. All perforations occurred within the first week of life (average 72 hr). All perforations were on the greater curvature of the fundus. The operative mortality of this series is 7.5% (1 of 13) with an overall mortality of 25% (4 of 16). A gastrostomy was routinely done. No peritoneal cavity drainage or segmental gastric resection was necessary.

Sonography in acute appendicitis.

In two patients with an equivocal clinical diagnosis of acute appendicitis, high-resolution sonography demonstrated an inflamed appendix. The appendix of each appeared grossly abnormal and was removed at laparotomy. Pathologic examination confirmed the diagnosis of acute appendicitis. Coupled with a review of the literature, the authors suggest high-resolution sonography as the examination of choice in patients with equivocal clinical findings of acute appendicitis.

IMRT clinical implementation: prostate and pelvic node irradiation using Helios and a 120-leaf multileaf collimator.

Dynamic intensity modulated radiation therapy (IMRT) to treat prostate and pelvic nodes using the Varian 120-leaf Millennium multileaf collimator (MLC) has been implemented in our clinic. This paper describes the procedures that have been undertaken to achieve this, including some of the commissioning aspects of Helios, verification of the dynamic dose delivery, and quality assurance (QA) of the dose delivered to the patient. Commissioning of Helios included measurements of transmission through the 120-leaf MLC, which were found to be 1.7% for 6 mV and 1.8% for 10 MV. The rounded leaf edge effect, known as the dosimetric separation, was also determined using two independent methods. Values of 1.05 and 1.65 mm were obtained for 6 and 10 MV beams. Five test patients were planned for prostate and pelvic node irradiation to 70 and 50 Gy, respectively. Dose and fluence verification were carried out on specially designed phantoms and dose points in the prostate were measured to be within 2.0% (mean 0.9%, s.d. 0.6%) of the calculated dose and in the nodes within 3.0% (mean 1.6%, s.d. 1.1%). Following the results of this commissioning and implementation study, we have started to treat men with a target Volume including the prostate and pelvic nodes using Helios optimized dynamic IMRT delivery in a dose escalation protocol.