Comparative Planning Study Research Articles

Whole breast proton irradiation for maximal reduction of heart dose in breast cancer patients.

Purpose In left-sided breast cancer radiotherapy, tangential intensity modulated radiotherapy combined with breath-hold enables a dose reduction to the heart and left anterior descending (LAD) coronary artery. Aim of this study was to investigate the added value of intensity modulated proton therapy (IMPT) with regard to decreasing the radiation dose to these structures. Methods In this comparative planning study, four treatment plans were generated in 20 patients: an IMPT plan and a tangential IMRT plan, both with breath-hold and free-breathing. At least 97 % of the target volume had to be covered by at least 95 % of the prescribed dose in all cases. Specifically with respect to the heart, the LAD, and the target volumes, we analyzed the maximum doses, the mean doses, and the volumes receiving 5–30 Gy. Results As compared to IMRT, IMPT resulted in significant dose reductions to the heart and LAD-region even without breath-hold. In the majority of the IMPT cases, a reduction to almost zero to the heart and LAD-region was obtained. IMPT treatment plans yielded the lowest dose to the lungs. Conclusions With IMPT the dose to the heart and LAD-region could be significantly decreased compared to tangential IMRT with breath-hold. The clinical relevance should be assessed individually based on the baseline risk of cardiac complications in combination with the dose to organs at risk. However, as IMPT for breast cancer is currently not widely available, IMPT should be reserved for patients remaining at high risk for major coronary events.

Volumetric modulated arc therapy versus step-and-shoot intensity modulated radiation therapy in the treatment of large nerve perineural spread to the skull base: a comparative dosimetric planning study.

IntroductionCutaneous squamous cell carcinoma with large nerve perineural (LNPN) infiltration of the base of skull is a radiotherapeutic challenge given the complex target volumes to nearby organs at risk (OAR). A comparative planning study was undertaken to evaluate dosimetric differences between volumetric modulated arc therapy (VMAT) versus intensity modulated radiation therapy (IMRT) in the treatment of LNPN.MethodsFive consecutive patients previously treated with IMRT for LNPN were selected. VMAT plans were generated for each case using the same planning target volumes (PTV), dose prescriptions and OAR constraints as IMRT. Comparative parameters used to assess target volume coverage, conformity and homogeneity included V95 of the PTV (volume encompassed by the 95% isodose), conformity index (CI) and homogeneity index (HI). In addition, OAR maximum point doses, V20, V30, non-target tissue (NTT) point max doses, NTT volume above reference dose, monitor units (MU) were compared.ResultsIMRT and VMAT plans generated were comparable for CI (P = 0.12) and HI (P = 0.89). VMAT plans achieved better V95 (P = < 0.001) and reduced V20 and V30 by 652 cubic centimetres (cc) (28.5%) and 425.7 cc (29.1%), respectively. VMAT increased MU delivered by 18% without a corresponding increase in NTT dose.ConclusionCompared with IMRT plans for LNPN, VMAT achieved comparable HI and CI.

Intensity Modulated Arc Therapy in Bilaterally Irradiated Head and Neck Cancer: A Comparative and Prospective Multicenter Planning Study

A dosimetric comparison was made of Helical Tomotherapy (HT) and Rapid'Arc® (RA) in 115 patients with head and neck carcinoma included in a prospective and multicentric study. HT and RA provided highly conformal plans that easily complied with dose volume constraints for organs at risk. HT reduced high doses to the planning target volumes (PTVs) compared to RA and provided a more homogeneous dose distribution but with an increased Non Tumoral Integral Dose (NTID) than RA. However, the clinical consequences of these dosimetric advantages and disadvantages need further investigation.

Taking path dependence seriously: an historical institutionalist research agenda in planning history

This paper outlines an historical institutionalist (HI) research agenda for planning history. HI approaches to the understanding of institutions, path dependence, positive feedback effects in public policy, and patterned processes of institutional change offer a robust theoretical framework and a valuable set of conceptual and analytic tools for the analysis of continuity and change in public policy. Yet, to date, there has been no systematic effort to incorporate historical institutionalism into planning history research. The body of the paper proposes planning history relevant definitions of institutions, path dependence, critical junctures, and incremental change processes, outlines recent HI literature applying and extending these concepts, and frames a number of research questions for planning history that these approaches suggest. A concluding section explores the potential application and leverage of HI approaches to the study of planning history and international comparative planning studies and outlines a research agenda.

A comparative planning study of step -and -shoot IMRT versus helical tomotherapy IMRT in the treatment of craniospinal tumor

A comparative planning study of step -and -shoot IMRT versus helical tomotherapy IMRT in the treatment of craniospinal tumor

EP-1590: Is IMRT superior to 3D-CRT for post-mastectomy loco-regional irradiation? An in silico comparative planning study

EP-1590: Is IMRT superior to 3D-CRT for post-mastectomy loco-regional irradiation? An in silico comparative planning study

A comparative planning study of step-and-shoot IMRT versus helical tomotherapy in a model patient

In order to assess the potential benefit of being able to use non-coplanar beams in a step-andshoot intensity-modulated radiotherapy (ssIMRT) differently from helical tomotherapy (HT), we performed a comparative planning evaluation in a model patient whose clinical target volumes enclosed critical normal tissue lying in the same plane. A patient with extensively relapsed malignant lymphoma in the circumferential chest wall was selected for comparison. Multiple, separated gross tumors were delineated, and the clinical target volume included the circumferential chest wall containing gross tumor volumes so that the critical organ, the right lung was fully enclosed. Three types of plans were analyzed; the first one was ssIMRT using only coplanar beams, the second was ssIMRT using non-coplanar beams, and the third was HT. The obtained results showed that dose homogeneity inside the gross tumor volume was better in the case of HT than noncoplanar ssIMRT and coplanar ssIMRT. However, the volume fraction of the right lung receiving a high dose was much smaller in the noncoplanar ssIMRT. As far as the dose to the clinical target volume (CTV) fully enclosing the right lung is concerned, not only the dose coverage of the CTV but also the dose homogeneity and conformity in the noncoplanar ssIMRT was better than in both of HT and the coplanar ssIMRT. We can conclude that appropriate isodose coverage for a complex target, which fully encloses a critical organ lying in the same plane, can be achieved by using a non-coplanar beam arrangement with no enforced penalty of higher dose to a critical organ.

Opening up the Compendium: An Evaluation of International Comparative Planning Research Methodologies

It is two decades since the European Compendium of Spatial Planning Systems and Policies was conceived. Since its publication in 1997, the Compendium has become a widely cited reference in comparative planning literature.1 It remains one of the few comprehensive reviews of spatial planning policy and practice across western Europe. The Compendium also represents one of the few studies to develop a typology for distinguishing between national planning systems. A number of comparative research studies on spatial planning have since built on the methodological foundations laid by the Compendium although its typology of national planning systems is not always used or interpreted as originally intended for a variety of reasons. In the context of extensive reform of planning approaches in Europe, the paper examines what can be learned about methodologies for international comparative research in planning based on the experience of the Compendium study and subsequent major comparative planning studies. We conclude that while broad typologies remain useful in explaining general trends, they may hide as much as they reveal. Future studies should widen the criteria used to build ideal types beyond formal characteristics in order to address planning in practice.

SU‐E‐T‐603: Evaluation of MLC‐Based Robotic Radiotherapy

Purpose: A multi‐leaf collimator (MLC) system has been introduced for the CyberKnife M6 system, enabling conformal shaping of beam apertures in robotic radiotherapy. Through a multi‐disease site study, the potential for the use of MLC‐based robotic delivery is assessed for conventionally fractionated regimens. Methods: The InCise MLC, consisting of 41 leaf pairs, with leaf thickness of 2.5 mm at 800 mm SAD, and a maximum field‐of‐view field size of 120 mm × 100 mm was used in conjunction with the MultiPlan 5.0 platform for comparative planning study relative to the pseudo‐conical IRIS variable aperture collimator. Conformal avoidance technique with relaxed convergence was used for the optimization, and identical dose‐volume optimization parameters and normalization (95%) for the comparative studies. Disease sites, including the prostate, partial breast, and peri‐orbit carcinomas were evaluated, and the results were quantified with respect to total monitor units (MUs), treatment time, conformality, and dose‐volume coverage. Results: The MLC system results on average of 3– 4 modulated segments for a series of non‐coplanar nodes. Relative to plans generated by the IRIS variable aperture collimators, the MLC‐based plans resulted in a 38±10% reduction of both the MUs and treatment time. While similar dosimetry is achieved by both systems, for a dose rate of 1000 MU/min, it is shown that treatment times of less than 20 minutes are possible for most conventionally fractionated treatments with the MLC system. Conclusion: A limiting factor in the adaptation of the robotic delivery for conventional radiotherapy has been the prolonged treatment times. The introduction of compact MLC fixture enables reduction of MUs and treatment time, making conventionally fractionated treatments feasible to more efficiently leverage the higher delivering accuracy and intrafraction motion correction capabilities of robotic delivery.

Protons in Head-and-Neck Cancer: Bridging the Gap of Evidence

To use Normal Tissue Complication Probability (NTCP) models and comparative planning studies to explore the (cost-)effectiveness of swallowing sparing intensity modulated proton radiotherapy (IMPT) compared with swallowing sparing intensity modulated radiotherapy with photons (IMRT) in head and neck cancer (HNC). A Markov model was constructed to examine and compare the costs and quality-adjusted life years (QALYs) of the following strategies: (1) IMPT for all patients; (2) IMRT for all patients; and (3) IMPT if efficient. The assumption of equal survival for IMPT and IMRT in the base case analysis was relaxed in a sensitivity analysis. Intensity modulated proton radiation therapy and IMRT for all patients yielded 6.620 and 6.520 QALYs and cost €50,989 and €41,038, respectively. Intensity modulated proton radiation therapy if efficient yielded 6.563 QALYs and cost €43,650. The incremental cost-effectiveness ratio of IMPT if efficient versus IMRT for all patients was €60,278 per QALY gained. In the sensitivity analysis, IMRT was more effective (0.967 QALYs) and less expensive (€8218) and thus dominated IMPT for all patients. Cost-effectiveness analysis based on normal tissue complication probability models and planning studies proved feasible and informative and enables the analysis of individualized strategies. The increased effectiveness of IMPT does not seem to outweigh the higher costs for all head-and-neck cancer patients. However, when assuming equal survival among both modalities, there seems to be value in identifying those patients for whom IMPT is cost-effective.

RapidArc®vsintensity-modulated radiation therapy for hepatocellular carcinoma: a comparative planning study

The purpose of this study is to compare the dose-volumetric results of RapidArc (RA Varian Medical Systems, Palo Alto, CA) with those of intensity-modulated radiation therapy (IMRT) for hepatocellular carcinoma. 20 patients previously treated for hepatocellular carcinoma were the subjects of this planning study. 10 patients were treated for portal vein tumour thrombosis (Group A), and 10 patients for primary liver tumour (Group B). Prescription dose to the planning target volume was 54 Gy in 30 fractions, and the planning goal was to deliver more than 95% of prescribed dose to at least 95% of planning target volume. In Group A, mean doses to liver were increased with RA vs IMRT (22.9 Gy vs 22.2 Gy, p=0.0275). However, V(30 Gy) of liver was lower in RA vs IMRT (31.1% vs 32.1%, p=0.0283). In Group B, in contrast, neither mean doses nor V(30 Gy) of liver significantly differed between the two plans. V(35 Gy) of duodenum and V(20 Gy) of kidney were decreased with RA in Groups A and B, respectively (p=0.0058 and 0.0124, respectively). Both maximal doses to spinal cord and monitor unit were significantly lower in the RA plan, regardless of the group. The dose-volumetric results of RA vs IMRT were different according to the different target location within the liver. In general, RA tended to be more effective in the sparing of non-liver organs at risk such as duodenum, kidney, and/or spinal cord. Moreover, RA was more efficient in the treatment delivery than IMRT in terms of total monitor unit used.

Randomized Clinical Trials Using New Technologies in Radiation Oncology: Ethical Dilemma for Medicine and Science

In this issue of the Journal of Thoracic Oncology, Dr. Roelofs et al. present the results of multicenter comparative planning study of 25 consecutive stage I–IIIA non-small cell lung cancer (NSCLC) patients with the use of three-dimensional conformal photon (3DCRT), intensity modulated photon (IMRT), and passive scattered proton radiotherapy (ROCOCO study).1 The patients were scanned with four-dimensional 18F-fluorodeoxyglucose-positron emission tomography/computed tomography and targets were delineated at the Department of Radiation Oncology, Maastricht University. Subsequently, participating centers used their own treatment planning systems according to predefined criteria and reported their plans through a centralized database. The results are shown according to two scenarios—with prescribed dose of 70 Gy in 35 fractions to planning target volume and by adapting the fraction dose to fulfill the toxicity criteria for organs at risk (isotoxic dose escalation per fraction). This and other in silico trials in radiotherapy raise several important issues. Rapid technological progress in diagnostic and therapeutic use of radiation allows for more accurate treatment planning and higher dose delivery to the tumor. This often leads to change in standard of care without documenting the benefit of the innovative intervention by conclusive phase III trial—a widely accepted golden standard in the era of evidencebased medicine. Indeed, radiation oncologists are tempted to rely on better dose distribution within the tumor volumes and on assuming the benefit from known dose-response relationships if exposure to organs at risk may be reduced. The widespread introduction of IMRT to clinical practice in head and neck, prostate, and many other cancers serves as a good example. A review of clinical evidence for IMRT has identified 61 comparative prospective studies, including only six randomized controlled trials, powered mostly for comparison of toxicity and not efficacy.2 Most of these studies became available when many radiation oncology departments already adopted IMRT. Not surprisingly, acute and late toxicity has consistently been shown to be improved with IMRT, whereas the benefit in local control or health-related quality of life has been less apparent. The limited number of randomized studies addressing the benefit of new technologies in radiotherapy underlines the difficulties in performing such studies. Is randomization ethical in the case of clearly worse dose distribution to organs at risk? Should dose escalation to the tumor be performed with new radiotherapy techniques when dose constraints for organs at risk are fulfilled? Prospective assessment of outcome measures remains extremely important, particularly when fundamentally different innovative radiation technologies, such as proton therapy, are applied. The benefits in efficacy, toxicity, and quality of life endpoints should be quantified to better understand the magnitude of benefit and also for incremental cost-effectiveness analyses. The ROCOCO study provides several important findings. The authors should be complimented for their multi-institutional collaboration in careful modeling of potential

Planned gentrification in istanbul: the sulukule renewal area 2005-2010

This paper evaluates the fi rst local government-led neighborhood regeneration project in central Istanbul with reference to its neighborhood impact and its wider implications for the future of regeneration in the city. From a perspective rooted in historical and international comparative planning studies, the research methodology is elaborated through an analysis of the evolution of a generic model of contemporary sustainable urban regeneration that provides the analytical framework for the evaluation. A review of the emergence of regeneration in Istanbul since the early 2000s establishes the context and rationale for the Sulukule case study. The paper then presents an analysis of events which led to the total demolition of the historic Sulukule neighborhood and the destruction of its Roma community. These events fl owed from the authoritarian implementation of the Sulukule Renewal Area Plan, despite the efforts of civil society organizations to secure the development and implementation of a community-based alternative plan. The neighborhood level evaluation explains why the redevelopment of Sulukule should be understood as planned gentrifi cation. Evaluation on a wider front is necessary because Sulukule has become the cause celebre in a vigorous debate about the purpose, scope, and outcomes of regeneration, which centers on the question ‘whose Historic Peninsula?’. Many argue that regeneration should be stopped, as it inevitably means planned gentrifi cation. But others, including the authors, draw on international experience to argue for the development of an Istanbul/Turkish version of sustainable, conservation-led, and community-based neighborhood regeneration. More widely still, the Sulukule experience has fuelled growing opposition to regeneration per se, epitomized in the slogan ‘no Sulukule here’. Thus the paper concludes by outlining the action needed to move toward sustainable regeneration, not only for the city’s central historic neighborhoods, but also for the far more numerous poor and deteriorating 20 th century neighborhoods where the threat is not from gentrifi cation, but

Intensity-Modulated Arc Therapy for Pediatric Posterior Fossa Tumors

To compare intensity-modulated arc therapy (IMAT) to noncoplanar intensity-modulated radiation therapy (IMRT) in the treatment of pediatric posterior fossa tumors. Nine pediatric patients with posterior fossa tumors, mean age 9 years (range, 6-15 years), treated using IMRT were chosen for this comparative planning study because of their tumor location. Each patient's treatment was replanned to receive 54 Gy to the planning target volume (PTV) using five different methods: eight-field noncoplanar IMRT, single coplanar IMAT, double coplanar IMAT, single noncoplanar IMAT, and double noncoplanar IMAT. For each method, the dose to 95% of the PTV was held constant, and the doses to surrounding critical structures were minimized. The different plans were compared based on conformity, total linear accelerator dose monitor units, and dose to surrounding normal tissues, including the entire body, whole brain, temporal lobes, brainstem, and cochleae. The doses to the target and critical structures for the various IMAT methods were not statistically different in comparison with the noncoplanar IMRT plan, with the following exceptions: the cochlear doses were higher and whole brain dose was lower for coplanar IMAT plans; the cochleae and temporal lobe doses were lower and conformity increased for noncoplanar IMAT plans. The advantage of the noncoplanar IMAT plan was enhanced by doubling the treatment arc. Noncoplanar IMAT results in superior treatment plans when compared to noncoplanar IMRT for the treatment of posterior fossa tumors. IMAT should be considered alongside IMRT when treatment of this site is indicated.

A RapidArc planning strategy for prostate with simultaneous integrated boost

Since the clinical implementation of novel rotational forms of intensity‐modulated radiotherapy, a variety of planning studies have been published that reinforce the major selling points of the technique. Namely, comparable or even improved dose distributions with a reduction in both monitor units and treatment times, when compared with static gantry intensity‐modulated radiotherapy. Although the data are promising, a rigorous approach to produce these plans has yet to be established. As a result, this study outlines a robust and streamlined planning strategy with a concentration on RapidArc class solutions for prostate with a simultaneous integrated boost. This planning strategy outlines the field setup, recommended starting objectives, required user interactions to be made throughout optimization and post‐optimization adjustments. A comparative planning study, with static gantry IMRT, is then presented as justification for the planning strategy itself. A variety of parameters are evaluated relating to both the planning itself (optimization and calculation time) and the plans that result. Results of this comparative study are in line with previously published data, and the planning process is streamlined to a point where the RapidArc optimization time takes 15±1.3 minutes. Application of this planning strategy reduces the dependence of the produced plan on the experience of the planner, and has the potential to streamline the planning process within radiotherapy departments.PACS numbers: 87.55.x, 87.55.D, 87.55.de, 87.55.dk

Predicted Risk of Radiation-Induced Cancers After Involved Field and Involved Node Radiotherapy With or Without Intensity Modulation for Early-Stage Hodgkin Lymphoma in Female Patients

To assess the excess relative risk (ERR) of radiation-induced cancers (RIC) in female patients with Hodgkin lymphoma (HL) female patients treated with conformal (3DCRT), intensity modulated (IMRT), or volumetric modulated arc (RA) radiation therapy. Plans for 10 early-stage HL female patients were computed for 3DCRT, IMRT, and RA with involved field RT (IFRT) and involvednode RT (INRT) radiation fields. Organs at risk dose--volume histograms were computed and inter-compared for IFRT vs. INRT and 3DCRT vs. IMRT/RA, respectively. The ERR for cancer induction in breasts, lungs, and thyroid was estimated using both linear and nonlinear models. The mean estimated ERR for breast, lung, and thyroid were significantly lower (p < 0.01) with INRT than with IFRT planning, regardless of the radiation delivery technique used, assuming a linear dose-risk relationship. We found that using the nonlinear model, the mean ERR values were significantly (p < 0.01) increased with IMRT or RA compared to those with 3DCRT planning for the breast, lung, and thyroid, using an IFRT paradigm. After INRT planning, IMRT or RA increased the risk of RIC for lung and thyroid only. In this comparative planning study, using a nonlinear dose--risk model, IMRT or RA increased the estimated risk of RIC for breast, lung, and thyroid for HL female patients. This study also suggests that INRT planning, compared to IFRT planning, may reduce the ERR of RIC when risk is predicted using a linear model. Observing the opposite effect, with a nonlinear model, however, questions the validity of these biologically parameterized models.

Minimising contralateral breast dose in post-mastectomy intensity-modulated radiotherapy by incorporating conformal electron irradiation

Purpose To assess the potential benefit of incorporating conformal electron irradiation in intensity-modulated radiotherapy (IMRT) for loco-regional post-mastectomy RT. Patients and methods Ten consecutive patients that underwent left-sided mastectomy were selected for this comparative planning study. Three-dimensional conformal radiotherapy (3D-CRT) photon–electron dose plans were compared to photon-only IMRT (IMRT p) and photon IMRT with conformal electron irradiation (IMRT p/e). The planning target volume (PTV) was prescribed 50 Gy and included the chest wall and the internal mammary and supra-clavicular lymph node regions. It was attempted to minimise dose delivered to heart, lungs and contralateral breast (CB), while maintaining adequate PTV coverage. Results All plans complied with objectives for PTV coverage. IMRT p/e eliminated volumes receiving ⩾70 Gy (V70) that were present in 3D-CRT at the junction of photon and electron beams. Both IMRT strategies reduced heart V30 significantly below 3D-CRT levels. Mean heart dose with IMRT p/e was the lowest and was equal to that with 3D-CRT. Minimising heart dose with IMRT p resulted in irradiated CB volumes much larger than that with 3D-CRT. With IMRT p/e, CB dose was only slightly increased when compared to 3D-CRT. Mean lung dose values were similar for IMRT and 3D-CRT. With IMRT, lung V20 was smaller, whereas V5 values for heart, lung and CB were higher than those with 3D-CRT. Conclusions Incorporation of conformal electron irradiation in post-mastectomy IMRT p/e enables a heart dose reduction which can only be obtained with IMRT p when allowing large irradiated volumes in the contralateral breast.

Dynamic Jaws and Dynamic Couch in Helical Tomotherapy

To investigate the next generation of helical tomotherapy delivery with dynamic jaw and dynamic couch movements. The new technique of dynamic jaw and dynamic couch movements is described, and a comparative planning study is performed. Ten nasopharyngeal cancer patients with skull base infiltration were chosen for this comparison of longitudinal dose profiles using regular tomotherapy delivery, running-start-stop treatment, and dynamic jaw and dynamic couch delivery. A multifocal simultaneous integrated boost concept was used (70.4Gy to the primary tumor and involved lymph nodes; 57.4Gy to the bilateral cervical lymphatic drainage pathways, 32 fractions). Target coverage, conformity, homogeneity, sparing of organs at risk, integral dose, and radiation delivery time were evaluated. Mean parotid dose for all different deliveries was between 24.8 and 26.1Gy, without significant differences. The mean integral dose was lowered by 6.3% by using the dynamic technique, in comparison with a 2.5-cm-field width for regular delivery and 16.7% with 5-cm-field width for regular delivery. Dynamic jaw and couch movements reduced the calculated radiation time by 66% of the time required with regular 2.5-cm-field width delivery (199 sec vs. 595 sec, p < 0.001). The current delivery mode of helical tomotherapy produces dose distributions with conformal avoidance of parotid glands, brain stem, and spinal cord. The new technology with dynamic jaw and couch movements improves the plan quality by reducing the dose penumbra and thereby reducing the integral dose. In addition, radiation time is reduced by 66% of the regular delivery time.

2037 Involved node and involved field volumetric modulated arc vs. fixed beam intensity modulated radiotherapy for female patients with early stage Hodgkin lymphoma: a comparative planning study

2037 Involved node and involved field volumetric modulated arc vs. fixed beam intensity modulated radiotherapy for female patients with early stage Hodgkin lymphoma: a comparative planning study

Volumetric Intensity-Modulated Arc Therapy Vs. Conventional IMRT in Head-and-Neck Cancer: A Comparative Planning and Dosimetric Study

Volumetric intensity-modulated arc therapy (RA) allows for rapid delivery of highly conformal dose distributions. In this study, planning and dosimetry of RA were compared with conventional intensity-modulated radiation therapy (IMRT) plans of head-and-neck cancer patients. Computed tomography scans of 12 patients who had completed IMRT for advanced tumors of the naso-, oro- and hypopharynx were replanned using RA using either one or two arcs. Calculated doses to planning target volume (PTV) and organs at risk (OAR) were compared between IMRT and RA plans. Dose distributions for single arc (n = 8) and double arc (n = 4) plans were verified using film dosimetry in three to five coronal planes using a quality assurance phantom. RA plans allowed for a mean reduction in number of monitor units (MU) by nearly 60%, relative to seven field sliding window IMRT plans. RA plans achieved similar sparing of all OAR as IMRT. Double arc RA provided the best dose homogeneity to PTV with a lower standard deviation of PTV dose (1.4 Gy), vs. single arc plans (2.0 Gy) and IMRT (1.7 Gy). Film measurements showed good correspondence with calculated doses; the mean gamma value was 0.30 (double arc) and area of the film with a gamma exceeding 1 was 0.82%. RA is a fast, safe, and accurate technique that uses lower MUs than conventional IMRT. Double arc plans provided at least similar sparing of OAR and better PTV dose homogeneity than single arc or IMRT.