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With recent clinical adoption of online adaptive radiation therapy (oART) and the increased workload associated with adaptive radiation therapy (RT), proper staffing for medical physicists is paramount to safe clinical operation. However, there is currently no consensus on the full-time equivalent (FTE) requirements for safe administration of cone beam computed tomography (CBCT)-guided oART. This study aimed to quantitatively assess medical physics workload and staffing needs of a CBCT-guided oART program. We conducted a detailed analysis of the CBCT-guided adaptive planning and treatment workflows, encompassing tasks such as patient consultation, treatment planning, plan review, training, quality assurance, and treatment delivery. Using data from machine logs, clinical database queries, and staff surveys, we present a framework for estimating FTE values for different staffing scenarios, considering medical physicists' roles as planners, adaptors, or both. FTE calculations, based on an example workload of 100 adaptive and 200 nonadaptive patients per year, for 3 staffing scenarios were provided: medical physicists as planners and adaptors (2.9 FTE), medical physicists as planners but not adaptors (2.6 FTE), and medical physicists as adaptors but not planners (1.4 FTE). These findings offer calculation guidance and benchmarks for staffing requirements in CBCT-guided oART programs, emphasizing the need for specific staffing models to accommodate the complexities of adaptive RT. This study outlines a framework for calculating FTE requirements for medical physicists in a CBCT-guided oART program. By analyzing the processes for 3 common adaptive RT workflows, this work can provide effective workforce planning and resource allocation estimates. This analysis can be used either before the implementation of an oART program, for program development, or as a review of current practices to ensure operational efficiency and proper staffing levels are maintained. [ABSTRACT FROM AUTHOR]

Although standardization has been shown to improve patient safety and improve the efficiency of workflows, implementation of standards can take considerable effort and requires the engagement of all clinical stakeholders. Engaging team members includes increasing awareness of the proposed benefit of the standard, a clear implementation plan, monitoring for improvements, and open communication to support successful implementation. The benefits of standardization often focus on large institutions to improve research endeavors, yet all clinics can benefit from standardization to increase quality and implement more efficient or automated workflow. The benefits of nomenclature standardization for all team members and institution sizes, including success stories, are discussed with practical implementation guides to facilitate the adoption of standardized nomenclature in radiation oncology. [ABSTRACT FROM AUTHOR]

Stereotactic body radiation therapy (SBRT) is increasingly used as a definitive treatment option for patients with prostate adenocarcinoma. The aim of this study was to assess the late toxicity, patient-reported quality of life outcomes, and biochemical recurrence rates after prostate SBRT with simultaneous integrated boost (SIB) targeting lesions defined by magnetic resonance imaging (MRI). Patients were eligible if they had biopsy-proven low- or intermediate-risk prostate adenocarcinoma, one or more focal lesions on MRI, and an MRI-defined total prostate volume of <120 mL. All patients received SBRT delivered to the entire prostate to a dose of 36.25 Gy in 5 fractions with an SIB to the lesions seen on MRI to 40 Gy in 5 fractions. Late toxicity was defined as any possible treatment-related adverse event occurring after 3 months from the completion of SBRT. Patient-reported quality of life was ascertained using standardized patient surveys. A total of 26 patients were enrolled. Six patients (23.1%) had low-risk disease and 20 patients had intermediate-risk disease (76.9%). Seven patients (26.9%) received androgen deprivation therapy. Median follow-up was 59.5 months. No biochemical failures were observed. Three patients (11.5%) experienced late grade 2 genitourinary (GU) toxicity requiring cystoscopy, and 7 patients (26.9%) had late grade 2 GU toxicity requiring oral medications. Three patients (11.5%) had late grade 2 gastrointestinal toxicity characterized by hematochezia requiring colonoscopy and steroids per rectum. There were no grade 3 or higher toxicity events observed. The patient-reported quality-of-life metrics at the time of last follow-up were not significantly different than the pre-treatment baseline. The results of this study support that SBRT to the entire prostate to a dose of 36.25 Gy in 5 fractions with focal SIB to 40 Gy in 5 fractions has excellent biochemical control and is not associated with undue late gastrointestinal or GU toxicity or long-term quality of life decrement. Focal dose escalation with an SIB planning approach may be an opportunity to improve biochemical control while limiting dose to nearby organs at risk. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to summarize treatment guidelines for the performance of single isocenter LINAC radiosurgery of multiple brain metastases developed and used by 3 experienced centers. This article is not meant to provide consensus guidelines. Rather, this is a practical, "how we do it" reference without substantial discussion. To serve as a treatment reference, the great majority of the information is presented in topic-specific tables. [ABSTRACT FROM AUTHOR]

Properly planned single isocenter volumetric modulated arc therapy (VMAT) radiosurgery plans exhibit high quality and efficiency. We report here the largest clinical experience to date, to our knowledge, comparing manual planning with a new automated platform designed to standardize and simplify radiosurgery planning and delivery processes. We treated 693 patients with single isocenter VMAT radiosurgical plans generated by either our conventional manual (mVMAT) or a recently implemented automated (HyperArcTM) technique. All plans targeted the gross tumor volume without margin. Radiochromic film was used for patient-specific quality assurance (PSQA). We evaluated local control and toxicity data for a subgroup of 107 patients having 377 metastatic tumors that were treated with HyperArc. The median Radiation Therapy Oncology Group (RTOG) conformity index was 1.14 and was not different between the 2 techniques. The median Paddick gradient index was 5.42 for HyperArc versus 7.09 for mVMAT (P <.001). The median mean brain doses were 4.6% and 5.1% for HyperArc and mVMAT, respectively (P =.04). The PSQA for both techniques met clinical criteria, but 97% of the HyperArc plans satisfied the gamma tolerance limit recommended by the American Association of Physicists in Medicine Task Group No. 218, compared with 94% of the mVMAT plans (P =.02). The median treatment-planning times were not significantly different. The median treatment times were 10.5 and 11.4 minutes for HyperArc and mVMAT, respectively (P <.001). The Kaplan-Meier estimate of local control was 90.1% at 1 year. HyperArc produces high-quality radiosurgical plans that are at least as good as mVMAT plans created by an expert manual planner with easier planning and more efficient delivery workflow. A less experienced planner can produce very high-quality radiosurgical plans even for patients with more than 10 targets. The use of a single-isocenter technique for multiple targets with no PTV margin did not compromise clinical outcomes, and 1-year local control for treated targets remained congruent with historical series. [ABSTRACT FROM AUTHOR]

The Calypso Beacon transponder has been modified by the addition of a nitinol anchor feature to allow for positional stability when implanted bronchoscopically into the lung. The purpose of this study was to confirm the feasibility and safety of anchored transponder placement and feasibility of lung target localization and tracking. This study enrolled patients with histologically confirmed cancer in the lung (primary or metastatic) who were scheduled to receive external beam radiation therapy. Three anchored transponders were implanted via flexible bronchoscopy into small (approximately 2- to 2.5-mm diameter) airways. Patient alignment at each radiation fraction was performed with the Calypso system, and anchored transponder position was tracked during radiation delivery. The primary endpoint was defined as the ability to localize at least 85% of the patients during the first week of treatment. Four follow-up visits were specified including a posttreatment assessment and every 3 months up to 1 year. A total of 69 patients underwent anchored transponder placement, and all 207 implanted anchored transponders were visible on the treatment-planning simulation computed tomography scan. Sixty-seven patients underwent radiation therapy, and localization was successful in 66 cases (98.5%). With 1 failure in 67 cases, the P value for rejecting the null hypothesis was <.001 and the primary objective of the study met. Five adverse events in 5 patients were potentially attributed to the study device or implantation procedure, consisting of pneumonia (2 cases), pleural abscess (1 case), and pneumothorax (2 cases). Two serious events (cardiac arrest and acute hypotension) were attributed to anesthesia during the implantation procedure. This study strongly supports that anchored transponders are safe, positionally stable, and useful for lung tumor localization and monitoring. [ABSTRACT FROM AUTHOR]

This report details our institutional workflow and technique for use of the Calypso electromagnetic transponder system with respiratory gating for localization and tracking of lung tumors during stereotactic radiation therapy for early stage thoracic malignancies. Sixteen patients underwent bronchoscopic fiducial placement of 3 transponders in small airways in proximity to the primary tumor. Transponders were placed <19 cm from the most anterior skin location of the patient for appropriate tracking functionality. Patients underwent simulation with 4-dimensional assessment and were treated with transponder based positional gating if tumors moved >5 mm in any direction. Tumor motion <5 mm was not gated and treated using an internal target volume approach. A 5 mm uniform planning target volume was used. Before treatment, fiducial placement and tumor location were verified by daily kilovoltage (kV) and cone beam computed tomography image guidance. Tracking limits were placed based on the movement of the transponders from the centroid of the structures on the maximum intensity projection image. The Calypso treatment system paused treatment automatically if beacons shifted beyond the predefined tracking limits. All 16 patients underwent successful implantation of the electromagnetic transponders. Eight patients exhibited tumor motion sufficient to require respiratory gating, and the other 8 patients were treated using a free breathing internal target volume technique. Difficulty with transponder sensing was experienced in 3 patients as a result of anatomic interference with the placement of the sensing arrays; each of these cases was successfully treated after making setup modifications. Triggered imaging of fiducials during treatment was consistent with real-time positioning determined by the Calypso tracking system. Respiratory gated electromagnetic based transponder guided stereotactic body radiation therapy using the workflow described is feasible and well tolerated in selected patients with early stage lung malignancies. [ABSTRACT FROM AUTHOR]

Intensity modulated radiation therapy (IMRT) is widely used in the treatment of head and neck cancers (HNC). There is not enough evidence to suggest that some radiation oncologists (ROs) are associated with better outcomes in patients with HNC. We conducted a cross-sectional analysis to evaluate the effect of ROs' characteristics on outcomes in patients with HNC treated with IMRT. The study used the Surveillance Epidemiology and End Results-Medicare linked database to identify patient characteristics. Physician records were obtained from the American Medical Association. Logistic regression models with propensity scores were analyzed to look for an association between RO characteristics and patient outcomes. RO characteristics showed that approximately 30% of ROS completed their training in or after the year 2000 (recently trained), and 17% were in top decile of treatment volume (high volume). Less than 3% of ROs work in academic settings. We found that ROs who were recently trained have higher odds (odds ratio [OR]: 1.10; 95% confidence interval [CI], 1.011-1.191) compared with those who were not. In addition, ROs who were treating high volumes of patients have higher odds (OR: 1.08; 95% CI, 1.010-1.165) compared with those treating low volumes of an event of adverse effect of IMRT or death among patients. ROs who work in academic settings have a protective effect (OR: 0.72; 95% CI, 0.569-0.925). ROs who were recently trained and had a high treatment volume are associated with poorer outcomes among patients with HNC who receive IMRT treatment. [ABSTRACT FROM AUTHOR]

Background Radiosurgery is becoming an increasingly used modality for the medically inoperable early stage lung cancer patient. The optimal fiducial marker with respect to retention rate has yet to be identified. Methods We retrospectively reviewed our experience with electromagnetic navigational bronchoscopic fiducial marker placement in preparation for stereotactic radiosurgery. Results Forty-eight patients, treated between 2010 and January 2013, were retrospectively reviewed. All patients had a diagnosis of early stage lung cancer. Comparison of initial fiducial placement procedure data with imaging at the time of treatment was accomplished for all patients in this data set. Fiducial retention rates were as follow: VortX coil fiducials were retained in 59 of 61 (96.7%) cases; two-band fiducials were retained in 24 of 33 (72.7%) of instances; and gold seed fiducials were retained in 23 of 33 (69.7%) of cases. Retention was statistically superior when comparing the VortX coil with the two-band fiducial or the gold seed ( p = 0.004 and p = 0.0001). Anatomic location by lobe was analyzed, but no statistically significant differences were observed. Conclusions The VortX coil fiducial marker showed a statistically significant increase in retention rate compared with gold seeds or two-band fiducials. This may translate to cost savings through placing fewer markers per patient as retention is high. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this study was to determine whether radiation dose inhomogeneity within the prostate predisposes to late urinary strictures after moderately hypofractionated definitive external beam radiation therapy for prostate cancer. Methods and materials One hundred seventy-three men with clinically localized prostate cancer met the inclusion criteria for this analysis. All patients received 70 Gy to the prostate delivered over 28 fractions, had at least 2 years of clinical follow-up, and had dose-volume histogram information available for review. The endpoint of this study was the development of a urethral stricture that required a procedural intervention such as urethral dilation or suprapubic catheterization. Dosimetric parameters were evaluated for effect on the rate of urethral stricture formation by univariate Cox proportional hazards modeling. Results The median follow-up was 49.5 months (range, 24.6-108 months). At 5 years, the actuarial rate of intervention for urethral strictures across all patients was 4.9%. The maximum point dose within the prostate ( P = .034, hazard ratio = 1.006) and the mean prostate dose ( P = .039, hazard ratio = 1.004) were the only parameters predictive of urethral stricture formation. All patients who developed a urethral stricture were treated by a plan with a maximum prostate dose of > 75 Gy (median, 77.67 Gy). Conclusions For patients receiving moderately hypofractionated prostate radiation therapy over 28 fractions, a maximum point dose of 75 Gy within the prostate was associated with an increased probability of developing a urethral stricture that required procedural intervention. The hypothesis that hypofractionation increases susceptibility to toxicity from heterogeneity within the prostate should be confirmed by analyzing data from randomized trials with a conventionally fractionated control arm for comparison. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To demonstrate plan quality and provide a practical, systematic approach to the treatment planning technique for single isocenter cranial radiosurgery with volumetric modulated arc therapy (VMAT; RapidArc, Varian Medical systems, Palo Alto, CA). Methods and materials: Fifteen patients with 1 or more brain metastases underwent single isocenter VMAT radiosurgery. All plans were normalized to deliver 100% of the prescription dose to 99%-100% of the target volume. All targets per plan were treated to the same dose. Plans were created with dose control tuning structures surrounding targets to maximize conformity and dose gradient. Plan quality was evaluated by calculation of conformity index (CI = 100% isodose volume/target volume) and homogeneity index (HI = maximum dose/prescription dose) scores for each target and a Paddick gradient index (GI = 50% isodose volume/100% isodose volume) score for each plan. Results: The median number of targets per patient was 2 (range, 1-5). The median number of non-coplanar arcs utilized per plan was 2 (range, 1- 4). Single target plans were created with 1 or 2 non-coplanar arcs while multitarget plans utilized 2 to 4 non-coplanar arcs. Prescription doses ranged from 5-16 Gy in 1-5 fractions. The mean conformity index was 1.12 (± SD, 0.13) and the mean HI was 1.44 (± SD, 0.11) for all targets. The mean GI per plan was 3.34 (± SD, 0.42). Conclusions: We have outlined a practical approach to cranial radiosurgery treatment planning using the single isocenter VMAT platform. One or 2 arc single isocenter plans are often adequate for treatment of single targets, while 2-4 arcs may be more advantageous for multiple targets. Given the high plan quality and extreme clinical efficiency, this single isocenter VMAT approach will continue to become more prevalent for linac-based radiosurgical treatment of 1 or more intracranial targets and will likely replace multiple isocenter techniques. [Copyright &y& Elsevier]

Purpose: To evaluate treatment planning and delivery for patients treated during our initial year of experience with RapidArc™ radiation therapy. Methods and Materials: RapidArc was used to treat 52 patients at The University of Alabama at Birmingham between May 2008 and April 2009. A single ionization chamber phantom with film and a two-dimensional ionization chamber array were used for quality assurance measurements. Of the 52 patients, 44 had a static gantry dynamic multileaf collimated (SG-DMLC) IMRT treatment plan, seven of which had quality assurance (QA) measurements. Results: The mean difference between ionization chamber measurement and calculation was 1.2% ± 0.9% (1 standard deviation). For film, the mean fraction of pixels with γ > 1 (3%/3 mm criterion) was 4.6% and for the two-dimensional chamber array was 1.4%. For the seven corresponding SG-DMLC plans, the results were similar. Differences in important dosimetric indicators were typically within 1% relative to SG-DMLC. The volume of nontarget tissue that received >20 Gy was less for RapidArc compared with SG-DMLC, whereas the volume that received more than 10 Gy was larger. The mean difference between the measured and planned leaf positions and the monitor units obtained from machine log files was 0.0 ± 0.5 mm and 0.4 ± 0.3 MU, respectively. Mean delivery times were 1.5 ± 0.2 and 3.3 ± 0.4 min for one- and two-arc plans, respectively. On average, SG-DMLC delivery took 4.4 min longer. Conclusions: RapidArc plans have quality comparable to our standard SG-DMLC IMRT technique, and are delivered with similar accuracy in shorter time. [Copyright &y& Elsevier]

Purpose: To evaluate the relative plan quality of single-isocenter vs. multi-isocenter volumetric modulated arc therapy (VMAT) for radiosurgical treatment of multiple central nervous system metastases. Methods and Materials: VMAT plans were created using RapidArc technology for treatment of simulated patients with three brain metastases. The plans consisted of single-arc/single-isocenter, triple-arc (noncoplanar)/single-isocenter, and triple-arc (coplanar)/triple-isocenter configurations. All VMAT plans were normalized to deliver 100% of the 20-Gy prescription dose to all lesions. The plans were evaluated by calculation of Paddick and Radiation Therapy Oncology Group conformity index scores, Paddick gradient index scores, and 12-Gy isodose volumes. Results: All plans were judged clinically acceptable, but differences were observed in the dosimetric parameters, with the use of multiple noncoplanar arcs showing small improvements in the conformity indexes compared with the single-arc/single-isocenter and triple-arc (coplanar)/triple-isocenter plans. Multiple arc plans (triple-arc [noncoplanar]/single-isocenter and triple-arc [coplanar]/triple-isocenter) showed smaller 12-Gy isodose volumes in scenarios involving three metastases spaced closely together, with only small differences noted among all plans involving lesions spaced further apart. Conclusion: Our initial results suggest that single-isocenter VMAT plans can be used to deliver conformity equivalent to that of multiple isocenter VMAT techniques. For targets that are closely spaced, multiple noncoplanar single-isocenter arcs might be required. VMAT radiosurgery for multiple targets using a single isocenter can be efficiently delivered, requiring less than one-half the beam time required for multiple isocenter set ups. VMAT radiosurgery will likely replace multi-isocenter techniques for linear accelerator-based treatment of multiple targets. [Copyright &y& Elsevier]

Purpose: To use angular beam''s-eye-view dosimetrics (BEVD) information to improve the computational efficiency and plan quality of inverse planning of aperture-modulated arc therapy (AMAT). Methods and Materials: In BEVD-guided inverse planning, the angular space spanned by a rotational arc is represented by a large number of fixed-gantry beams with angular spacing of ∼2.5 degrees. Each beam is assigned with an initial aperture shape determined by the beam''s-eye-view (BEV) projection of the planning target volume (PTV) and an initial weight. Instead of setting the beam weights arbitrarily, which slows down the subsequent optimization process and may result in a suboptimal solution, a priori knowledge about the quality of the beam directions derived from a BEVD is adopted to initialize the weights. In the BEVD calculation, a higher score is assigned to directions that allow more dose to be delivered to the PTV without exceeding the dose tolerances of the organs at risk (OARs) and vice versa. Simulated annealing is then used to optimize the segment shapes and weights. The BEVD-guided inverse planning is demonstrated by using two clinical cases, and the results are compared with those of a conventional approach without BEVD guidance. Results: An a priori knowledge–guided inverse planning scheme for AMAT is established. The inclusion of BEVD guidance significantly improves the convergence behavior of AMAT inverse planning and results in much better OAR sparing as compared with the conventional approach. Conclusions: BEVD-guidance facilitates AMAT treatment planning and provides a comprehensive tool to maximally use the technical capacity of the new arc therapeutic modality. [Copyright &y& Elsevier]

Purpose: To study the effect on tumor control probability of selectively boosting the dose to hypoxic subvolumes.Methods and Materials: A Monte Carlo model was developed that separates the tumor into two compartments, one of which receives a primary dose, and one of which receives a higher boost dose. During radiation delivery, each compartment consists of three clonogen subpopulations: those that are well oxygenated, those that are temporarily hypoxic (geometrically transient hypoxia), and those that are permanently hypoxic (geometrically stable hypoxia). The spatial location of temporary hypoxia within the tumor volume varies over time, whereas, the spatial location of permanent hypoxia does not. The effect of reoxygenation was included. Clonogen proliferation was not included in the model.Results: A modest boost dose (120%–150% of the primary dose) increases tumor control probability to that found in the absence of permanent hypoxia. The entire hypoxic subvolume need not be included to obtain a significant benefit. However, only tumors with a geometrically stable hypoxic volume will have an improved control rate.Conclusions: Tumors with an identifiable geometrically stable hypoxic volume will have an improved control rate if the dose to the hypoxic volume is escalated. Further work is required to determine the spatiotemporal evolution of the hypoxic volumes before and during the course of radiotherapy. [Copyright &y& Elsevier]

Purpose The purpose of this study was to evaluate dose prescription and recording compliance to international standard (International Commission on Radiation Units & Measurements [ICRU]-83) in patients treated with intensity modulated radiation therapy (IMRT) among academic institutions. Methods and materials Ten institutions participated in this study to collect IMRT data to evaluate compliance to ICRU-83. Under institutional review board clearance, data from 5094 patients—including treatment site, technique, planner, physician, prescribed dose, target volume, monitor units, planning system, and dose calculation algorithm—were collected anonymously. The dose-volume histogram of each patient, as well as dose points, doses delivered to 100% (D 100 ), 98% (D 98 ), 95% (D 95 ), 50% (D 50 ), and 2% (D 2 ), of sites was collected and sent to a central location for analysis. Homogeneity index (HI) as a measure of the steepness of target and is a measure of the shape of the dose-volume histogram was calculated for every patient and analyzed. Results In general, ICRU recommendations for naming the target, reporting dose prescription, and achieving desired levels of dose to target were relatively poor. The nomenclature for the target in the dose prescription had large variations, having every permutation of name and number contrary to ICRU recommendations. There was statistically significant variability in D 95, D 50 , and HI among institutions, tumor site, and technique with P values < .01. Nearly 95% of patients had D 50 higher than 100% (103.5 ± 6.9) of prescribed dose and varied among institutions. On the other hand, D 95 was close to 100% (97.1 ± 9.4) of prescribed dose. Liver and lung sites had a higher D 50 compared with other sites. Pelvic sites had a lower variability indicated by HI (0.13 ± 1.21). Variability in D 50 is 101.2 ± 8.5, 103.4 ± 6.8, 103.4 ± 8.2, and 109.5 ± 11.5 for IMRT, tomotherapy, volume modulated arc therapy, and stereotactic body radiation therapy with IMRT, respectively. Conclusions Nearly 95% of patient treatments deviated from the ICRU-83 recommended D 50 prescription dose delivery. This variability is significant ( P < .01) in terms of treatment site, technique, and institution. To reduce dosimetric and associated radiation outcome variability, dose prescription in every clinical trial should be unified with international guidelines. [ABSTRACT FROM AUTHOR]

We present a framework for collecting data which elucidates detailed clinical flow timelines for different treatment sites, modalities, planners, and physicians in radiotherapy treatments. A web based tool, the Whiteboard, was developed which allows communication between the physicians and staff about the current state of the radiotherapy treatment plan and provides detailed time data for each stage of the patient's journey from simulation to treatment. Detailed timestamped data was collected over a period of 6 years which included 22 discrete steps of the treatment planning process. Whiteboard data was combined with data in the treatment planning database Aria (Varian Medical Systems, Palo Alto, CA) using the Eclipse Scripting API to include treatment plan information. Over 6 years, 110,477 patient statuses were time-logged for 9683 courses of treatment using our Whiteboard software, which allowed determination of patient volumes per individual and the time to perform planning tasks. The mean planning volume per dosimetrist was 375.8 ± 142.4 plans and 71.03 ± 27.10 plan revisions per year. The mean planning volume per physician was 218.9 ± 110.8 plan approvals with 41.55 ± 43.73 plan revisions per year. Physician contour time was a mean of 79.59 ± 84.61 hours, but varied greatly by diagnosis category and physician. The longest median modality planning time of 119.6 hours was for the IMRT plans with 8 or more fields. The shortest median times were 48.25, 49.53, and 50.98 hours for plans with 5, 4, and 3 fields, respectively. We demonstrated a framework that could help facilities in staff planning and aid in workload distribution, and could be used to improve understanding of radiotherapy timelines for patients, payers, and other institutions involved in radiotherapy processes. [ABSTRACT FROM AUTHOR]

A substantial barrier to the single- and multi-institutional aggregation of data to supporting clinical trials, practice quality improvement efforts, and development of big data analytics resource systems is the lack of standardized nomenclatures for expressing dosimetric data. To address this issue, the American Association of Physicists in Medicine (AAPM) Task Group 263 was charged with providing nomenclature guidelines and values in radiation oncology for use in clinical trials, data-pooling initiatives, population-based studies, and routine clinical care by standardizing: (1) structure names across image processing and treatment planning system platforms; (2) nomenclature for dosimetric data (eg, dose-volume histogram [DVH]-based metrics); (3) templates for clinical trial groups and users of an initial subset of software platforms to facilitate adoption of the standards; (4) formalism for nomenclature schema, which can accommodate the addition of other structures defined in the future. A multisociety, multidisciplinary, multinational group of 57 members representing stake holders ranging from large academic centers to community clinics and vendors was assembled, including physicists, physicians, dosimetrists, and vendors. The stakeholder groups represented in the membership included the AAPM, American Society for Radiation Oncology (ASTRO), NRG Oncology, European Society for Radiation Oncology (ESTRO), Radiation Therapy Oncology Group (RTOG), Children's Oncology Group (COG), Integrating Healthcare Enterprise in Radiation Oncology (IHE-RO), and Digital Imaging and Communications in Medicine working group (DICOM WG); A nomenclature system for target and organ at risk volumes and DVH nomenclature was developed and piloted to demonstrate viability across a range of clinics and within the framework of clinical trials. The final report was approved by AAPM in October 2017. The approval process included review by 8 AAPM committees, with additional review by ASTRO, European Society for Radiation Oncology (ESTRO), and American Association of Medical Dosimetrists (AAMD). This Executive Summary of the report highlights the key recommendations for clinical practice, research, and trials. [ABSTRACT FROM AUTHOR]

Objective To investigate the effect of hypofractionated external beam radiation therapy (RT) on sexual function in patients treated for localized prostate cancer, and also to determine the effect of radiation dose to the penile bulb or crura of the corpus cavernosum on sexual function outcome. Materials and Methods Forty-one patients treated with hypofractionated RT without androgen deprivation were prescribed 67.6-70.2 Gy to the prostate, delivered in 26-28 fractions. The primary endpoint was erectile dysfunction (ED) category based on the Sexual Health Inventory for Men (SHIM) score closest to 2 years from RT. The penile bulb and crura were contoured and mean radiation dose calculated for each structure. Results The mean pretreatment SHIM score was 19.8, and the mean posttreatment SHIM score was 15.1. The ED category was decreased by ≥2 in 50% of patients with a mean penile bulb of >20 Gy compared with that in 9% of patients with a mean penile bulb dose of ≤20 Gy ( P = .003). Mean dose to the crura was highly correlated with mean dose to the penile bulb (Pearson correlation = 0.842; P <.001) but did not reach statistical significance as a predictor of ED after radiation. Conclusion Radiation dose to the penile bulb is predictive of posttreatment ED in patients treated with dose-escalated hypofractionated prostate RT. The cutpoint at which this effect was observed with this treatment is substantially lower than the previous reports. [ABSTRACT FROM AUTHOR]

Abstract: The clinical application of intensity modulated radiotherapy (IMRT) for adjuvant treatment of breast cancer has been the subject of increasing study in recent years. IMRT results in improved target coverage, reduced dose inhomogeneity within the breast, and reduced dose to the heart, lungs, and contralateral breast. However, this has been at the cost of larger volumes of low-dose radiation to these structures, thus increasing the theoretic risk for second malignancies. Our goal was to develop an IMRT beam arrangement that did not result in additional low-dose spill to organs at risk while maintaining equal or better target coverage. Five patients with early-stage left-sided breast cancer, who underwent breast conservation surgery and adjuvant radiation therapy, were chosen for this comparative study. The conventional radiation treatment (CRT) plan was comprised of standard wedged tangential fields. An IMRT plan consisting of 6 tangential beams (3 medial and 3 lateral) was generated by using the gantry, collimator, and table angles of the standard plan used for the CRT plan, and moving the table +10° and −10° on each side. The prescription dose for both CRT and IMRT plans was 45 Gy, 1.8 Gy/fraction, prescribed to the isocenter, which was placed near the center of the breast. IMRT plans provided significantly better coverage of the left breast than the CRT plans (p = 0.03). Although the dose heterogeneity was greater with the IMRT plans, the difference was not significant (p = 0.68). The mean volumes of the heart, lung, and right breast were lower in patients planned with IMRT at all dose levels from 5% to 100% dose (5% increments). This difference was significant for volumes receiving 2.25 Gy for the heart (p = 0.003), and volumes receiving 2.25, 4.5, 6.75, 33.75, 36, 38.25, and 42.75 Gy for the lung (p = 0.014, 0.04, 0.044, 0.05, 0.049, 0.045, and 0.05, respectively). Surprisingly, breast IMRT resulted in significantly lower right breast volumes irradiated at all dose levels compared to CRT. A 6-tangential-field IMRT technique achieved significantly better left breast coverage while maintaining lower doses to risk organs at all dose levels and therefore reduced the potential for induction of a second malignancy. [Copyright &y& Elsevier]

Purpose: Intensity modulated radiation therapy (IMRT) has been shown to significantly reduce dose to normal tissue while maintaining coverage of the clinical target volume (CTV) in patients with intact breast cancer. We compared delivery of whole breast irradiation utilizing three techniques: electronic tissue compensation (ECOMP), inverse-planned dynamic multileaf collimation IMRT (DMLC), and tomotherapy (TOMO). Patients and Methods: Ten patients with early stage, left-sided breast cancer were selected for planning. CTV was defined as breast encompassed in a standard tangent field minus the superficial 5 mm from the skin edge. Normal tissue contours included the heart, lungs, and contralateral breast. Plans included delivery of 45 Gy in 25 fractions and were normalized to ensure > or =95% coverage of the CTV. Isodose distributions and dose-volume histograms for CTV and normal tissue were compared between plans. The time it took to plan each patient excluding contouring, as well as number of monitor units (MUs) required to execute each plan were additionally tabulated. Results: The TOMO plans resulted in significantly greater heterogeneity (CTV V(115)) versus ECOMP (p = 0.0029). The ECOMP plans resulted in significantly lower doses to heart, lung, and contralateral breast when compared with TOMO plans. The ECOMP plans were generated in the shortest time (12 min) and resulted in the lowest number of MUs when compared with DMLC (p = 0.002, p < 0.0001) and TOMO (p = 0.0015, p < 0.0001). Conclusions: The ECOMP plans produced superior dose distributions in both the CTV and normal tissue when compared with TOMO or DMLC plans. In addition, ECOMP plans resulted in the lowest number of MUs and labor cost. [ABSTRACT FROM AUTHOR]

Abstract: The treatment of maxillary sinus carcinoma with forward planning can be technically difficult when the neck also requires radiotherapy. This difficulty arises because of the need to spare the contralateral face while treating the bilateral neck. There is considerable potential for error in clinical setup and treatment delivery. We evaluated intensity-modulated radiotherapy (IMRT) as an improvement on forward planning, and compared several inverse planning IMRT platforms. A composite dose-volume histogram (DVH) was generated from a complex forward planned case. We compared the results with those generated by sliding window fixed field dynamic multileaf collimator (MLC) IMRT, using sets of coplanar beams. All setups included an anterior posterior (AP) beam, and 3-, 5-, 7-, and 9-field configurations were evaluated. The dose prescription and objective function priorities were invariant. We also evaluated 2 commercial tomotherapy IMRT delivery platforms. DVH results from all of the IMRT approaches compared favorably with the forward plan. Results for the various inverse planning approaches varied considerably across platforms, despite an attempt to prescribe the therapy similarly. The improvement seen with the addition of beams in the fixed beam sliding window case was modest. IMRT is an effective means of delivering radiotherapy reliably in the complex setting of maxillary sinus carcinoma with neck irradiation. Differences in objective function definition and optimization algorithms can lead to unexpected differences in the final dose distribution, and our evaluation suggests that these factors are more significant than the beam arrangement or number of beams. [Copyright &y& Elsevier]

Purpose: The conventional single-isocenter and half-beam (SIHB) technique for matching supraclavicular fields with head-and-neck (HN) intensity-modulated radiotherapy (IMRT) fields is subject to substantial dose inhomogeneities from imperfect accelerator jaw/MLC calibration. It also limits the isocenter location and restricts the useful field size for IMRT. We propose a dynamic field-matching technique to overcome these limitations. Methods and Materials: The proposed dynamic field-matching technique makes use of wedge junctions for the abutment of supraclavicular and HN IMRT fields. The supraclavicular field was shaped with a multileaf collimator (MLC), which was orientated such that the leaves traveled along the superoinferior direction. The leaves that defined the superior field border moved continuously during treatment from 1.5 cm below to 1.5 cm above the conventional match line to generate a 3-cm-wide wedge-shaped junction. The HN IMRT fields were optimized by taking into account the dose contribution from the supraclavicular field to the junction area, which generates a complementary wedge to produce a smooth junction in the abutment region. This technique was evaluated on a polystyrene phantom and 10 HN cancer patients. Treatment plans were generated for the phantom and the 10 patients. Dose profiles across the abutment region were measured in the phantom on films. For patient plans, dose profiles that passed through the center of the neck lymph nodes were calculated using the proposed technique and the SIHB technique, and dose uniformity in the abutment region was compared. Field mismatches of +/- 1 mm and +/- 2 mm because of imperfect jaw/MLC calibration were simulated, and the resulting dose inhomogeneities were studied for the two techniques with film measurements and patient plans. Three-dimensional volumetric doses were analyzed, and equivalent uniform doses (EUD) were computed. The effect of field mismatches on EUD was compared for the two match techniques. Results: For a perfect jaw/MLC calibration, dose profiles for the 10 patients in the 3-cm match zone had an average inhomogeneity range of -1.6% to +1.6% using the dynamic-matching technique and -3.7% to +3.8% according to the SIHB technique. Measurements showed that dose inhomogeneities that resulted from 1-mm and 2-mm jaw/MLC calibration errors were reduced from as large as 27% and 45% with the SIHB technique to less than 2% and 5.7% with the dynamic technique, respectively. For -1-mm, -2-mm, +1-mm, and +2-mm jaw/MLC calibration errors, respectively, treatment plans for the 10 patients yielded average dose inhomogeneities of -5.9%, -3.0%, +2.7%, and +5.8% with the dynamic technique as compared to -22.8%, -11.1%, +9.8%, and +22.1% with the SIHB technique. Calculation based on a dose-volume histogram (DVH) showed that the SIHB technique resulted in larger changes in EUD of the PTV in the junction area than did the dynamic technique. Conclusion: Compared with the conventional SIHB technique, the dynamic field-matching technique provides superior dose homogeneity in the abutment region between the supraclavicular and HN IMRT fields. The dynamic feathering mechanism substantially reduces dose inhomogeneities that result from imperfect jaw/MLC calibration. In addition, isocenter location in the dynamic field-matching technique can be chosen for reproducible patient setup and for adequate IMRT field size rather than being dictated by the match position. It also allows angling of the supraclavicular field to reduce the volume of healthy lung irradiated, which is impractical with the SIHB technique. In principle, this technique should be applicable to any treatment site that requires the abutment of static and intensity-modulated fields. [ABSTRACT FROM AUTHOR]