HERO (Health Economics in Radiation Oncology): a pan-European project on radiotherapy resources and needs.

Radiotherapy continues to evolve at a rapid rate in technology and techniques, with both driving up costs in an era in which health care budgets are of increasing concern at every governmental level. Against this background, it is clear that the radiotherapy community needs to quantify the costs of state of the art practice and then to justify those costs through rigorous cost-effectiveness analyses. The European Society for Radiotherapy and Oncology-Health Economics in Radiation Oncology project is directed towards tackling this issue in the European context. The first step has been to provide a validated picture of the European radiotherapy landscape in terms of the availability of equipment, personnel and guidelines. An 84-item questionnaire was distributed to the 40 countries of the European Cancer Observatory, of which 34 provided partial or complete responses. There was a huge variation in the availability and sophistication of treatment equipment and staffing levels across Europe. The median number of MV units per million inhabitants was 5.3, but there was a seven-fold variation across the European countries. Likewise, although average staffing figures per million inhabitants were 12.8 for radiation oncologists, 7.6 for physicists, 3.5 for dosimetrists, 26.6 for radiation therapists and 14.8 for nurses, there was a 20-fold variation, even after grouping personnel with comparable duties in the radiotherapy process. Guidelines for capital and human resources were declared for most countries, but without explicitly providing metrics for developing capital and human resource inventories in many cases. Although courses delivered annually per resource item ­ be it equipment or staff ­ increase with decreasing gross national income (GNI) per capita, differences were observed in equipment and staff availability in countries with a higher GNI/n, indicating that health policy has a significant effect on the provision of services. Although more needs to be done to increase access to radiotherapy in Europe, the situation has improved considerably since the comparable RadioTherapy for Cancer: QUAnification of Infrastructure and Staffing Needs (QUARTS) study reported in 2005.

Consensus recommendations for incident learning database structures in radiation oncology.

PURPOSE: Incident learning plays a key role in improving quality and safety in a wide range of industries and medical disciplines. However, implementing an effective incident learning system is complex, especially in radiation oncology. One current barrier is the lack of technical standards to guide users or developers. This report, the product of an initiative by the Work Group on Prevention of Errors in Radiation Oncology of the American Association of Physicists in Medicine, provides technical recommendations for the content and structure of incident learning databases in radiation oncology. METHODS: A panel of experts was assembled and tasked with developing consensus recommendations in five key areas: definitions, process maps, severity scales, causality taxonomy, and data elements. Experts included representatives from all major North American radiation oncology organizations as well as users and developers of public and in-house reporting systems with over two decades of collective experience. Recommendations were developed that take into account existing incident learning systems as well as the requirements of outside agencies. RESULTS: Consensus recommendations are provided for the five major topic areas. In the process mapping task, 91 common steps were identified for external beam radiation therapy and 88 in brachytherapy. A novel feature of the process maps is the identification of "safety barriers," also known as critical control points, which are any process steps whose primary function is to prevent errors or mistakes from occurring or propagating through the radiotherapy workflow. Other recommendations include a ten-level medical severity scale designed to reflect the observed or estimated harm to a patient, a radiation oncology-specific root causes table to facilitate and regularize root-cause analyses, and recommendations for data elements and structures to aid in development of electronic databases. Also presented is a list of key functional requirements of any reporting system. CONCLUSIONS: Incident learning is recognized as an invaluable tool for improving the quality and safety of treatments. The consensus recommendations in this report are intended to facilitate the implementation of such systems within individual clinics as well as on broader national and international scales.

Poster - Thur Eve - 12: Dosimetric manifestation of harmonic mode imaging for seed implant brachytherapy.

PURPOSE: To demonstrate the dosimetric effects of observer variability in defining the prostate and critical organs, using Tissue Harmonic (H) ultrasound imaging mode for permanent seed implant brachytherapy. METHODS: Images were acquired using a B -K medical 8848 probe with Brightness (B) and H mode for ten prostate brachytherapy patients. The prostate, rectum and urethra were contoured independently by five observers. The clinically used treatment plans based on B mode imaging fulfilling the dosimetric criteria were applied on these contours. Dosimetric parameters (prostate: D90, V100 and V200; rectum: V100; urethra: V140, V150 and V160) were computed using SPOT PRO™ planning system. Interobserver variability in dosimetric parameters was tested using standard deviations as percentages of means. RESULTS: Two-factor analysis of variances showed significant (p<0.05) interobserver variability in all dosimetric parameters for both modes. Interobserver agreement in dosimetric parameters improves in H mode due to improved interobserver consistency in contouring these organs on H mode images compared to B mode. There is no significant difference observed (paired student t test, p>0.05) in the mean values of dosimetric parameters in H and B mode for prostate and critical organs. CONCLUSIONS: H mode due to its better image quality helped to improve the interobserver agreement in contouring the prostate and critical organs and hence better interobserver consistency in all dosimetric parameter. Because the difference in the mean value of dosimetric parameters between two imaging modes is not statistically significant, H mode does not appear to offer any clinical advantages in terms of improving the dosimetric outcome.

Defining the elements for successful implementation of a small-city radiotherapy department.

AIMS: Distributed delivery models for cancer care have been introduced to bring care closer to home and to provide better access to cancer patients needing radiotherapy. Very little work has been done to demonstrate the elements critical for success in a non-centralized approach. The present study set out to identify the elements that are important for implementing radiotherapy away from large cities. METHODS AND RESULTS: This qualitative research project consisted of two separate components. In the first component, structured interviews were conducted with 5 external experts. Input on the expert responses was then sought from internal leaders in medical physics, radiation therapy, and radiation oncology. Those interviews were used to develop a proposed template of the elements needed in a small-city department. We tested the validity of all elements by surveying staff members from the radiation treatment program in Calgary, leading to a definition of the resources needed for the proposed department in Lethbridge. Seventy-five staff members contributed to the survey. CONCLUSIONS: Qualitative research methods allowed us to define important elements for a small-city radiotherapy department and to validate those elements with a large cohort of staff working in a tertiary centre. This work has influenced the planning of a small-city department in Lethbridge, emphasizing the importance of the elements identified to the service planners. We await the completion of the construction project and the opening of the centre so that we can re-evaluate the importance of the identified elements in actual practice. We recommend such an approach to jurisdictions that are considering devolved radiotherapy.

A pre-clinical phantom comparison of tissue harmonic and brightness mode imaging for application in ultrasound guided prostate brachytherapy.

PURPOSE: The current practice of prostate brachytherapy utilizes the brightness (B) mode ultrasound imaging for volume definition and needle guidance. However, tissue harmonic (H) mode available with new scanners has shown the improved image quality. The aim of this study was to perform a pre-clinical phantom evaluation of harmonic imaging as an alternative to B mode in prostate brachytherapy. METHODS: Performance characteristics viz. dead zone, depth of penetration, geometric accuracy, spatial resolution, tissue to clutter ratio (TCR) and signal to noise ratio (SNR), were compared between two modes using an in-house phantom. Images were acquired under the same settings except the gain; which is higher for the H mode than that of B mode. A qualitative comparison between two modes was also performed using commercial CIRS053 phantom. RESULTS: Dead zone, depth of penetration and geometric accuracy were respectively <1 mm, >8 cm and <1% for both modes. Relative TCR, SNR and the spatial resolution were improved in H mode compared with B mode. Images with CIRS053 phantom in H mode demonstrate sharper boundaries for prostate and urethra, freedom from background clutter, and better identification of the brachytherapy needles. CONCLUSIONS: This study indicates the superiority of H over B mode, in terms of spatial resolution, relative contrast, and overall image quality. Thus H mode has the potential benefit in prostate brachytherapy. This study provides the basis to move forward to investigate whether the superior image quality observed in the laboratory can be translated into a higher treatment quality for the patient.

ICRP publication 112. A report of preventing accidental exposures from new external beam radiation therapy technologies.

Disseminating the knowledge and lessons learned from accidental exposures is crucial in preventing re-occurrence. This is particularly important in radiation therapy; the only application of radiation in which very high radiation doses are deliberately given to patients to achieve cure or palliation of disease. Lessons from accidental exposures are, therefore, an invaluable resource for revealing vulnerable aspects of the practice of radiotherapy, and for providing guidance for the prevention of future occurrences. These lessons have successfully been applied to avoid catastrophic events with conventional technologies and techniques. Recommendations, for example, include the independent verification of beam calibration and independent calculation of the treatment times and monitor units for external beam radiotherapy, and the monitoring of patients and their clothes immediately after brachytherapy. New technologies are meant to bring substantial improvement to radiation therapy. However, this is often achieved with a considerable increase in complexity, which in turn brings opportunities for new types of human error and problems with equipment. Dissemination of information on these errors or mistakes as soon as it becomes available is crucial in radiation therapy with new technologies. In addition, information on circumstances that almost resulted in serious consequences (near-misses) is also important, as the same type of events may occur elsewhere. Sharing information about near-misses is thus a complementary important aspect of prevention. Lessons from retrospective information are provided in Sections 2 and 4 of this report. Disseminating lessons learned for serious incidents is necessary but not sufficient when dealing with new technologies. It is of utmost importance to be proactive and continually strive to answer questions such as 'What else can go wrong', 'How likely is it?' and 'What kind of cost-effective choices do I have for prevention?'. These questions are addressed in Sections 3 and 5 of this report. Section 6 contains the conclusions and recommendations. This report is expected to be a valuable resource for radiation oncologists, hospital administrators, medical physicists, technologists, dosimetrists, maintenance engineers, radiation safety specialists, and regulators. While the report applies specifically to new external beam therapies, the general principles for prevention are applicable to the broad range of radiotherapy practices where mistakes could result in serious consequences for the patient and practitioner.

Poster - Thurs Eve-07: The dosimetric consequences of MLC position inaccuracy in IMRT.

The Multileaf Collimator (MLC), the most widely used means of intensity modulating beams for IMRT, is subject to random and systematic errors in leaf positions that may compromise the treatment quality. This work is a simulation study of the effect of random and systematic errors in leaf position on delivered dose distributions. The dosimetric effects of random errors of up to 2 mm and systematic errors (±1mm in 2 banks, ±0.5mm in 2 banks and 2mm in 1 bank of leaves) were analysed for a typical head and neck IMRT plan and a typical prostate IMRT plan. Dose Volume Histograms and Equivalent Uniform Doses (EUD) of the target volumes, bladder and rectum for the prostate plan and brainstem, larynx, parotids and spinal cord for the head and neck plan were calculated with and without MLC positioning errors and compared. The results show that if we adopt a 2% change in EUD of the target and 2 Gy for the OARs as acceptable levels of uncertainty in dose due to MLC effects only, then random errors of up to 2mm may be tolerated but systematic errors in leaf position will need to be limited to 0.5mm. Our study provides guidance, based on a surrogate of clinical outcome, for the development of quality control standards for multileaf collimators.

Towards an objective evaluation of tolerances for beam modeling in a treatment planning system.

The performance of a convolution/superposition based treatment planning system depends on the ability of the dose calculation algorithm to accurately account for physical interactions taking place in the tissue, key components of the linac head and on the accuracy of the photon beam model. Generally the user has little or no control over the performance of the dose calculation algorithm but is responsible for the accuracy of the beam model within the constraints imposed by the system. This study explores the dosimetric impact of limitations in photon beam modeling accuracy on complex 3D clinical treatment plans. A total of 70 photon beam models was created in the Pinnacle treatment planning system. Two of the models served as references for 6 MV and 15 MV beams, while the rest were created by perturbing the reference models in order to produce specific deviations in specific regions of the calculated dose profiles (central axis and transverse). The beam models were then used to generate 3D plans on seven CT data sets each for four different treatment sites (breast and conformal prostate, lung and brain). The equivalent uniform doses (EUD) of the targets and the principal organs at risk (OARs) of all plans ( approximately 1000) were calculated and compared to the EUDs delivered by the reference beam models. In general, accurate dosimetry of the target is most greatly compromised by poor modeling of the central axis depth dose and the horns, while the EUDs of the OARs exhibited the greatest sensitivity to beam width accuracy. Based on the results of this analysis we suggest a set of tolerances to be met during commissioning of the beam models in a treatment planning system that are consistent in terms of clinical outcomes as predicted by the EUD.

Intensity modulated and three-dimensional conformal radiation therapy plans for oropharyngeal cancer: a comparison of their sensitivity to set-up errors and uncertainties.

We compared the effect of set-up error and uncertainty on two radiation therapy treatment plans for head and neck cancer: one using intensity modulated radiation therapy (IMRT) and one using conventional three-dimensional conformal radiation therapy (3D-CRT). We used a Pinnacle3 (Philips Medical Systems, Markham, Ontario) system to create the two treatment plans (7-beam IMRT and 5-beam 3D-CRT) for the same volumetric data set, based on the objectives and constraints defined in the Radiation Therapy Oncology Group H-0022 protocol. In both plans, the dose-volume constraints for the targets and the organs at risk (oars) were met as closely as the beam geometries would allow. Monte Carlo-based simulations of set-up error and uncertainty were performed in three orthogonal directions for 840 simulated "courses of treatment" for each plan. A systematic error (chosen from distributions characterized by standard deviations ranging from 0 mm to 6 mm) and random uncertainties (2 mm standard deviation) were incorporated. We used a probability approach to compare the sensitivities of the IMRT and the 3D-CRT plans to set-up error and uncertainty in terms of equivalent uniform dose (EUD) to targets and oars.Based on the EUD analysis, the targets and oars showed considerably greater sensitivity to set-up error with the IMRT plan than with the 3D-CRT plan. For the IMRT plan, target EUDS were reduced by 4%, 7.5%, and 10% for 2-mm, 4-mm, and 6-mm set-up errors respectively. However, even with set-up error, the mandible, spinal cord, and parotid EUDS always remained lower with the IMRT plan than with the 3D-CRT plan.We conclude that, when quantified by EUD, IMRT-plan doses to oars and targets are more sensitive to set-up error than are 3D-CRT-plan doses. However, as judged by the differences between target and OAR doses, IMRT retains its superiority over 3D-CRT, even in the presence of set-up error.

The characterization of a promising new optical source for use with a radiotherapy treatment simulator.

We report on an experimental examination of a new powerful optical source with potential application in radiotherapy treatment simulation. The illuminance, effective source position, and source size have been measured for this new source and, for comparison, for conventional sources on a simulator and a linear accelerator. This new source is considerably brighter than those in common use in radiotherapy. Its effective optical source size is larger than that on the linear accelerator tested but comparable with that on a conventional simulator.

Radiotherapy service delivery models for a dispersed patient population.

Access to health care interventions can be impeded when significant patient travel is required. In this economic evaluation we compare, from a societal perspective, three scenarios for the delivery of radiation treatment to an idealized population of 1,600 patients distributed between two urban nodes (1,200 + 400 patients each) separated by up to 500 km. As it is implicitly assumed that the clinical outcome for those patients who access the system is independent of the service delivery model, this study constitutes a cost minimization analysis from a societal perspective. The costs to the health care system are based on an activity costing model developed by us and consistent with recent Canadian studies. The costs to the patient are approximated by a formula that includes direct costs (travel and accommodation) and indirect (time) costs, with the latter based on a human capital approach. A sensitivity analysis has been performed to confirm the robustness of our conclusions both to uncertainties in the input data and to the inclusion of time costs, the estimation of which remains controversial. From a societal cost perspective only, we show that outreach radiotherapy (central comprehensive facility and satellite) is the economically superior service delivery model for separations between 30 km and 170 km. Beyond 170 km, a fully decentralized service would be warranted if the only consideration were societal economic advantage.

A cost-outcome analysis of adjuvant postmastectomy locoregional radiotherapy in premenopausal node-positive breast cancer patients.

PURPOSE: To calculate cost-effectiveness and cost-utility ratios for adjuvant postmastectomy locoregional radiotherapy in premenopausal node-positive breast cancer patients and to place these ratios in the context of generally accepted medical expenditures. MATERIALS AND METHODS: A spreadsheet-based activity costing model using 1997 Canadian (cdn) capital, operating, and administrative costs has been used to identify, from the institutional perspective, the incremental cost of adding radiotherapy to surgery and chemotherapy for this group of patients. Outcome data were derived from two recently published clinical trials and were converted to discounted incremental life years and quality-adjusted life years gained. Recommended health economics principles were employed in the quantification of both costs and outcomes, and a sensitivity analysis was performed. Three referenced publications provide a context within which to evaluate the calculated cost-effectiveness and cost-utility ratios. RESULTS: The incremental cost of adjuvant radiotherapy for this group of patients is calculated to be approximately $7,000cdn in 1997 Canadian dollars and in the Canadian socialized health-care environment. Based on published work the discounted incremental outcome benefit is calculated to be 0.5 life years or 0.45 quality-adjusted life years at ten years. Thus, cost effectiveness and cost-utility ratios are estimated to be $14,000cdn and $15,600cdn, respectively. CONCLUSION: Within the context of generally accepted medical expenditures, adjuvant postmastectomy locoregional radiotherapy for premenopausal node-positive breast cancer patients would be regarded as a cost-effective treatment strategy.

An economic framework for evaluating a multileaf collimator.

OBJECTIVES: As health care budgets continue to face close scrutiny, any new acquisition must be evaluated for both costs and outcomes. This study was undertaken to demonstrate the application of an economic framework for the evaluation of a multileaf collimator as an example of a new technology that can have both quantifiable and nonquantifiable benefits for patients, staff, and cancer care institutions. METHODS: Using financial data from the Northeastern Ontario Regional Cancer Centre (NEORCC) and a recognized staffing model, a commercial spreadsheet, developed to economically characterize the principal radiotherapy processes has been used to determine the net incremental annual cost of a multileaf collimator (MLC). RESULTS: The incremental annual cost of purchasing an MLC is estimated at approximately $85,000 (1997 CDN $). Without increasing patient throughput, this increases the average cost of a course of radiotherapy by approximately CDN $200. Savings can be accrued by decreasing mold room activity, increasing the hourly patient capacity on each treatment machine, and decreasing sick time due to strain injuries. CONCLUSIONS: Although the clinical outcome of techniques facilitated by MLCs, such as intensity-modulated radiation therapy, are unknown at this time, an economic context within which to objectively evaluate this technology is presented. The framework presented suggests a method of quantifying outcome-justified expenditures, such as improved patient outcome and greater treatment flexibility, which, when offset against the incremental annual equipment cost, may be used to help justify the acquisition of multileaf technology.

Preventative maintenance and unscheduled downtime from an economic perspective.

A spreadsheet-based model for economically characterizing the operation of a radiation treatment program has been used to perform a quantitative financial analysis of scheduled and unscheduled downtime. The incremental cost of downtime is broken down into three categories: remuneration of in-house or third party service technologists, decreased patient capacity, and local operating procedures for dealing with downtime. Different service arrangements and operating procedures are simulated to demonstrate the financial cost of treatment machine unavailability due to either preventative maintenance or unexpected breakdown. Depending on the service arrangement and operating policies for accommodating downtime, the combined cost of scheduled and unscheduled downtime (at 5%) can exceed 10% of the total cost of the radiation treatment program. It has also been demonstrated that the greatest cost component of downtime is decreased patient capacity, which can exceed $400,000 (CAN) when unscheduled downtime reaches 5%. The interpretation of this cost depends on the funding environment. Although the emphasis of this study has been the financial consequences of downtime, there are other factors which must be considered when developing policies and procedures for accommodating downtime such as effects on treatment, patient convenience and quality of life for staff. Even though the numerical results are strictly valid only within the context of the simulations performed, they do provide a broad framework within which medical physicists can make recommendations regarding service support and downtime.

Independent corroboration of monitor unit calculations performed by a 3D computerized planning system.

The checking of monitor unit calculations is recognized as a vital component of quality assurance in radiotherapy. Using straightforward but detailed computer-based verification calculations it is possible to achieve a precision of 1% when compared with a three-dimensional (3D) treatment planning system monitor unit calculation. The method is sufficiently sensitive to identify significant errors and is consistent with current recommendations on the magnitude of uncertainties in clinical dosimetry. Moreover, the approach is accurate in the sense of being highly consistent with the validated 3D treatment planning system's calculations.

The cost of radiotherapy as a function of facility size and hours of operation.

Against a background of constant or decreasing budgets, this study was undertaken to investigate the economic effects of changes in selected operational parameters within a radiation treatment programme. Using financial data from the Northeastern Ontario Regional Cancer Centre and a recognized staffing model, a commercial spreadsheet has been used to calculate the cost of an 18 fraction course of radiotherapy, including all the major preparatory processes such as simulation and treatment planning. Using the spreadsheet, and on the basis of explicit and reasonable assumptions, the cost of radiotherapy has been calculated as the facility size (i.e. equipment complement) and hours of operation are varied. Based on the assumptions used, the cost of radiotherapy in a facility treating less than about 1600 patients per year starts to rise. At 400 patients per year, a course costs approximately 50% more than at 1600 patients per annum. Extended hours of operation do not appear to generate significant, if any, savings when realistic assumptions about machine lifetime and overtime payments are made. Using a spreadsheet to simulate changes in a radiation treatment programme can be an important decision-making tool, as the effects of changes in operating parameters can be demonstrated.

A test tool for the visual verification of light and radiation fields using film or an electronic portal imaging device.

We describe the design and evaluation of a simple test tool which can be used in conjunction with either film or an electronic portal imaging device (EPID) to verify light and radiation fields and their congruence. The precision of the technique is better than 0.5 mm under all conditions tested. When used with film the accuracy or offset of the technique (the difference between test tool observations and a scanned conventional film) is better than 0.5 mm but, with an EPID as the image receptor, the accuracy dropped to, in one trial, 0.86 mm. The offset may be due to a systematic observer bias in determining the 50% O.D. level on the image, compounded, in the case of EPID measurements, by image acquisition and display parameters. Thus, when used with an EPID, calibration of the system will be required if absolute field dimensions are required. When used with film, the test tool method described here is of sufficient accuracy and precision to confirm the compliance of light and radiation field parameters with currently accepted quality control protocols.

Intestinal metaplasia subtyping: evaluation of Gomori's aldehyde fuchsin for routine diagnostic use.

AIMS: Intestinal metaplasia (IM) has been implicated in the pathogenesis of gastro-oesophageal carcinoma, but because of its common occurrence, its specificity for use in cancer surveillance is low. IM subtypes characterized by mucin phenotype have been studied to try and improve specificity. METHODS AND RESULTS: On balance, type III IM seems the most promising for use in gastric cancer surveillance. The situation is problematic at the gastro-oesophageal junction where the normal occurrence of acidic mucins raises doubt on the value of subtyping. High iron diamine-Alcian blue combination (HID-AB) is commonly used for IM subtyping, but its potential toxicity and long staining period (up to 24 hours) precludes widespread clinical use. This study has compared the sulphomucin staining ability of Gomori's aldehyde fuchsin-Alcian blue combination (GAF-AB) against HID-AB for identifying and subtyping IM in gastric and oesophageal biopsies. CONCLUSIONS: Compared to HID-AB, a sensitivity of 85%, a specificity of 100% and a staining time of less than 30 minutes, shows this stain to be a simple and effective technique for identifying and subtyping IM in routine laboratories.

The Siemens virtual wedge.

A Siemens Virtual Wedge has recently been installed and commissioned at the Northeastern Ontario Regional Cancer Centre. Measurements reported below show that 1) Virtual Wedge factors are within 1.5% of 1; 2) percentage depth doses down to 15 cm for open and virtually wedged fields are identical to within 0.7%; 3) relative cross beam profiles for 60 degrees virtual and physical wedges are very similar except at the toe end where a 5% difference in relative dose has been observed and 4) the peripheral dose from the 60 degrees Virtual Wedge is about half of that from the 60 degrees physical wedge. A clinical protocol requiring combined open and 60 degrees wedged fields has been developed and validated. This protocol, which does not impair the utility of the Virtual Wedge, facilitates the use of on-line portal imaging and significantly reduces the effort required to commission the system.