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Primary bone lymphoma is a rare type of lymphoid neoplasm with favorable prognosis, where Primary Non Hodgkin Lymphoma of bone (PB-NHL) is most common with the subtype. Amongst PB-NHL, diffuse large Bcell lymphoma represents the majority of cases. The mandible is a very uncommon site of involvement, presenting as a painful bone mass with high suspicion of osteomyelitis.We report the case of a 45-year-old male with no significant past medical history who was admitted to the hospital with a large right jaw mass and pain after recent tooth removal. The original tissue biopsy was not diagnostic, and cultures were found to be negative for microorganisms. Due to enlargement of the mass, a fine needle aspiration (FNA) was done. At the time of rapid onsite evaluation of the FNA, atypical lymphoid cells were seen, and material was obtained for flow cytometry (FC) evaluation. This revealed an aberrant clonal B-cell population. The consequent immunohistochemical evaluation of original material supported the diagnosis of PB-NHL. After chemotherapy patient improved.After an extensive English language literature review, we identified and summarized the clinical presentations, diagnostic procedures, histopathologic features, treatment methods, and outcomes of forty-two cases of periodontal PB-NHL. Based on our findings, we propose a set of clinical features at initial presentation to increase the clinical suspicion of periodontal PB-NHL for practitioners.Based on our institution's experience and the literature review conclusions, we propose the University of Texas Medical Branch diagnostic approach for PB-NHL and suggest that FNA and FC should be utilized as the essential diagnostic component. The fast and efficient diagnosis of PB-NHL can facilitate the correct treatment and sufficiently improve patient care.

IntroductionOrgan-at-risk segmentation for head and neck cancer radiation therapy is a complex and time-consuming process (requiring up to 42 individual structure, and may delay start of treatment or even limit access to function-preserving care. Feasibility of using a deep learning (DL) based autosegmentation model to reduce contouring time without compromising contour accuracy is assessed through a blinded randomized trial of radiation oncologists (ROs) using retrospective, de-identified patient data.MethodsTwo head and neck expert ROs used dedicated time to create gold standard (GS) contours on computed tomography (CT) images. 445 CTs were used to train a custom 3D U-Net DL model covering 42 organs-at-risk, with an additional 20 CTs were held out for the randomized trial. For each held-out patient dataset, one of the eight participant ROs was randomly allocated to review and revise the contours produced by the DL model, while another reviewed contours produced by a medical dosimetry assistant (MDA), both blinded to their origin. Time required for MDAs and ROs to contour was recorded, and the unrevised DL contours, as well as the RO-revised contours by the MDAs and DL model were compared to the GS for that patient.ResultsMean time for initial MDA contouring was 2.3 hours (range 1.6-3.8 hours) and RO-revision took 1.1 hours (range, 0.4-4.4 hours), compared to 0.7 hours (range 0.1-2.0 hours) for the RO-revisions to DL contours. Total time reduced by 76% (95%-Confidence Interval: 65%-88%) and RO-revision time reduced by 35% (95%-CI,-39%-91%). All geometric and dosimetric metrics computed, agreement with GS was equivalent or significantly greater (pConclusionDL autosegmentation demonstrated significant time-savings for organ-at-risk contouring while improving agreement with the institutional GS, indicating comparable accuracy of DL model. Integration into the clinical practice with a prospective evaluation is currently underway.

Primary bone lymphoma (PBL) is a rare extranodal presentation within lymphomas and primary bone malignancies. Pathologic fracture (PF) is a common complication of metastatic bone disease but is, rarely, the presentation of a primary bone tumor. We report a case of an 83-year-old man with a history of untreated prostate cancer, presenting with atraumatic fracture of his left femur after months of intermittent pains and weight loss. Radiographic workup revealed a lytic lesion suspicious for PF secondary to metastatic prostate cancer; however, initial core biopsy results were inconclusive for malignancy. A complete blood count with differential and complete metabolic panel was within normal limits. During surgical fixation and nailing of the femur, a reaming biopsy was performed as a repeat measure and revealed diffuse large B-cell lymphoma. Staging with positron emission tomography and computed tomography found no evidence of lymphatic or visceral involvement and chemotherapy was promptly initiated. This case highlights the diagnostic workup challenges for PF secondary to PBL, especially in the setting of concurrent malignancy. Because of the non-specific presentation of a lytic lesion on imaging associated with atraumatic fracture, we highlight PBL as an important diagnostic consideration.

The purpose of this study was to examine if the use of a bolus helmet when treating the head with intensity modulated proton therapy (IMPT) will maintain organs at risk (OAR) sparing while improving the clinical target volume (CTV) coverage. A bolus helmet is a device that aims to improve on the traditionally used range shifter in proton therapy by improving dose distribution characteristics. Ten patients were retrospectively selected who had 2 separate treatment planning scans performed, a scan with the bolus helmet and a second scan without. Plans were created using both scans. Dose to organs at risk (OAR) including the left optic nerve, right optic nerve, optic chiasm, and normal brain minus CTV (brain-CTV), as well as CTV coverage were compared between the 2 plans. The use of the bolus helmet displayed lower mean OAR doses as well as higher CTV coverage, suggesting that use of the bolus helmet provides benefit when treating the head with IMPT.

The 2019 coronavirus (COVID-19) pandemic has affected medical physics and radiation oncology departments and the delivery of radiation therapy. Among the changes implemented in response to the onset of the pandemic was a shift to remote treatment planning by health care institutions. The purpose of this study was to determine whether the overall frequency of errors changed after the implementation of remote radiation therapy treatment planning during the COVID-19 pandemic. Reported incidents were obtained from an incident reporting database operated by a multisite cancer care facility in the Northeast. Researchers compared the frequency of reported events in a period prior to the start of the pandemic (March 2019 to February 2020) with a period after the onset of the pandemic (March 2020 to February 2021). No significant increase in reported incidents was detected suggesting the efficiency and safety of remote radiotherapy treatment planning.

Volumetric modulated arc therapy (VMAT) and 3D dynamic conformal arc therapy (DCAT) are 2 methods proven useful for the clinical implementation of stereotactic body radiation therapy (SBRT) for lung lesions however, similar comparisons of SBRT liver lesions are lacking. The purpose of this study was to determine if the conformity of dose, irradiated volume, and dose to organs at risk (OAR) are equivalent or improved with the use of DCAT as an alternative treatment method when compared to standard VMAT for SBRT delivery of palliative and early-stage liver lesions. Twenty patients with liver lesions sized 2.0 to 5.0 cm were selected for this study. Plans were created with both DCAT and VMAT techniques for each patient. Metrics evaluated included the mean heart, kidney, large bowel, small bowel, esophagus, and stomach doses, the lung volume receiving 20 Gy (V

Although auto-contouring methods were created to reduce the workload for the radiation oncology team, concern lies in whether auto-contouring can improve efficiency regarding generated contours of a treatment plan. Researchers have measured differences between auto-contouring algorithms and manual contour methods specific to the contouring of organs at risk (OAR). The problem lies in the paucity of literature specific to perceptions of auto-contouring and the impact on workflow efficiency. The purpose of this study was to measure medical dosimetrists' perceptions of how auto-contouring software impacts the treatment planning process. To measure perceptions, researchers surveyed medical dosimetrists about their perspectives on consistency and efficiency of auto-contouring during treatment planning. A (Qualtrics, Provo, UT) survey was created based on the 2 research questions in this study. The survey was distributed through email to 2598 full members of the American Association of Medical Dosimetrists (AAMD) who were certified by the MDCB; mostly medical dosimetrists but also included a small group of medical physicists. The email open rate was 39% (1024/2598) but the response rate for those who read the email was only 8.4% (86/1024). Of the survey respondents, 67% (59/86) used auto-contouring software; thus, eligible to complete the remainder of the survey. Majority of participants agreed that auto-contouring software decreases time spent contouring per patient; however, most agreed that manual contouring is more efficient. Therefore, it was inferred that a combination of both auto and manual contouring have an impact on workload efficiency.

In this era of patient-centered, outcomes-driven and adaptive radiotherapy, deep learning is now being successfully applied to tackle imaging-related workflow bottlenecks such as autosegmentation and dose planning. These applications typically require supervised learning approaches enabled by relatively large, curated radiotherapy datasets which are highly reflective of the contemporary standard of care. However, little has been previously published describing technical infrastructure, recommendations, methods or standards for radiotherapy dataset curation in a holistic fashion. Our radiation oncology department has recently embarked on a large-scale project in partnership with an external partner to develop deep-learning-based tools to assist with our radiotherapy workflow, beginning with autosegmentation of organs-at-risk. This project will require thousands of carefully curated radiotherapy datasets comprising all body sites we routinely treat with radiotherapy. Given such a large project scope, we have approached the need for dataset curation rigorously, with an aim towards building infrastructure that is compatible with efficiency, automation and scalability. Focusing on our first use-case pertaining to head and neck cancer, we describe our developed infrastructure and novel methods applied to radiotherapy dataset curation, inclusive of personnel and workflow organization, dataset selection, expert organ-at-risk segmentation, quality assurance, patient de-identification, data archival and transfer. Over the course of approximately 13 months, our expert multidisciplinary team generated 490 curated head and neck radiotherapy datasets. This task required approximately 6000 human-expert hours in total (not including planning and infrastructure development time). This infrastructure continues to evolve and will support ongoing and future project efforts.

The prone position is frequently used for breast irradiation in an effort to minimize dose to normal tissue and reduce skin toxicities. Immobilization required for prone breast irradiation can cause collision issues with the linear accelerator, disrupting treatment and negatively affecting the patient experience. The purpose of this retrospective study was to determine if an isocenter location guideline could be developed to prevent collisions with the prone breast immobilization device and gantry head, while still creating a clinically acceptable treatment plan. Clearance isocenter guidelines were established by measuring clearance between the Civco Horizon breast board and Varian linear accelerator. Fourteen patients with known clearance issues at a single institution were selected for this study and re-planned using clearance isocenter guidelines. Collision plans were compared to clearance plans created within the established clearance threshold through the institutions breast treatment guidelines based on arm II of the Radiation Therapy Oncology Group (RTOG) 1005 recommendations. Researchers in this study demonstrated clinical relevance by establishing that a clearance isocenter location guideline can be developed to prevent collisions with the prone breast immobilization and gantry head, while still creating a clinically acceptable treatment plan.

Patient quality assurance (QA) is a required part of the treatment care path, and plan failure can lead to increased personnel hours or delay of treatment. The recommendation by the American Association of Physicists in Medicine is that gamma analysis be used to evaluate measured volumetric modulated arc therapy plans. Vendors have developed many different measurement geometries for patient QA devices which could yield varying pass rates when used with the recommended tolerances, normalization, and criterion. For this study, clinically treated stereotactic body radiation therapy plans were used to evaluate differences in gamma dose tolerances and sampled dose distribution complexity for centralized or peripheral measurement geometries on a cylindrical phantom. Random errors were then introduced into a subset of these plans, and the differences in pass rates between the geometries were correlated with differences in the observed mathematical differences. Finally, a single clinically relevant target coverage deviation was introduced to another subset of plans to evaluate whether a particular geometry is measurably better at identifying clinically relevant errors. It was found that centralized geometries resulted in more lenient dose tolerances and less complex sampled dose distributions compared to peripheral geometries. Pass rates were uniformly lower in the peripheral measurement geometry, and the difference in pass rates between the geometries correlated strongly with the difference in dose tolerance and weakly with the difference in the chosen complexity metrics. However, neither of the geometries were sufficiently sensitive enough to detect clinically relevant changes to target coverage when using recommended tolerances and criteria, and no statistically significant difference was found between their pass rates. Given these findings, the authors concluded that stereotactic body radiation therapy plans could fail patient QA when measured in the peripheral geometry but pass in the centralized geometry, with possibly neither having correlation to true clinical deviation.

Musculoskeletal disorders (MSDs) account for almost 70 million physician office visits per year in the United States and are the most common workplace injuries. These are conditions involving the nerves, tendons, muscles, and supporting structures of the body. Previous studies have concluded that computer users are at high risk of developing work-related musculoskeletal disorders (WRMSDs). As computer users, medical dosimetrists are at risk of developing WRMSDs, yet there is a lack of information regarding the incidence of WRMSDs among medical dosimetrists. The purpose of this study was to determine the incidence of WRMSDs and variables of workstation ergonomics that contribute to the increased risk of WRMSDs in medical dosimetrists. A Qualtrics survey was created to support the 3 research questions guiding this study. The survey was distributed to 2,646 full members of the American Association of Medical Dosimetrists (AAMD), which included only certified medical dosimetrists (CMDs), via email. The distribution of email surveys sent through the AAMD email distribution list resulted in 988 emails opened, for a contact rate of 37% (988/2646). One hundred sixty-four responses were recorded yielding a completion rate of 17% (164/988). Fifty-five percent (90/163) of participants responded that they have experienced WRMSDs. Forty-four percent (289/652) of responses indicated WRMSDs have a slight or moderate interference on work. Sixty-two percent (94/152) of participants felt that their workstations were not ergonomically designed; even greater 68% (104/153) did not feel their workstations were designed for their individually needs. Of those respondents 64% (98/152) would like to see further adaptations made to their workspaces.

Background: Emerging research supports 3D printing can provide customizable, low-cost, and replicable items for application in occupational therapy, but more research is necessary to inform occupational therapists on why and how 3D printing would be applicable and feasible in practice. Method: This study is a cost-effective analysis aimed to identify practical considerations of a selection of 3D printed items in comparison to commercially available items. Ten items of adaptive equipment were downloaded from open-sourced 3D printing design websites and printed. The estimated cost of material was calculated and each print time was recorded. Items with comparable design and function were selected from a thorough internet search for analysis and comparison to the 3D printed items. Results: The results demonstrate that each 3D printed item had a positive benefit in terms of material cost and print time compared to the cost and shipping time of each comparable item. Conclusion: The 3D printed items were the more cost-effective for all items, but most significantly for niche designs with fewer available commercial alternatives. 3D printing successfully replicated commonly used adaptive equipment for a comparable cost, while allowing for customization and the ability to provide the item in-house to clients.

Radiation pneumonitis (RP) is a potential toxic side effect of thoracic radiotherapy. Optimal planning techniques must maintain tumor coverage while limiting dose to normal lung tissue to reduce the risk of patients developing RP. The addition of a noncoplanar arc may be beneficial by increasing treatment angles and providing an ideal dose distribution for tumor coverage while decreasing dose to organs at risk (OAR). The purpose of this research was to compare the effects on the normal bilateral lung tissue receiving 20 Gy, 10 Gy and 5 Gy (V20, V10, V5) and the mean lung dose (MLD) values when medial lung tumors are treated with 3 partial coplanar arcs vs 2 partial coplanar arcs combined with a partial sagittal arc. Researchers hypothesized that a beam arrangement of 2 partial coplanar arcs and 1 partial sagittal arc would reduce V20, V10, V5, and MLD values when compared to a 3 partial coplanar arc plan. In a retrospective study of 5 patients with bulky, medial right lung lesions without nodal involvement, cases were planned with both a noncoplanar and a coplanar arc geometry. Results were evaluated using a two-tailed t-test to determine the statistical significance (p < 0.05) of changes to total lung volume analyzation metrics when a noncoplanar sagittal arc was incorporated compared to the standard lung treatment using only coplanar arcs. Although some patient cases showed minor improvement in the V20, V10, V5, and MLD metrics, the study results were not statistically significant and showed no advantage with the introduction of an anterior sagittal arc over a coplanar beam arrangement.

Adequate dose homogeneity and full prescription dose delivery to the scalp still remains a dosimetric problem during scalp irradiation due to the anatomical shape of the cranium. Confounding variables such as gravity, the irregular and convex shape of the cranium, air gaps between scalp surface and commercial bolus, and potential inconsistencies in a 3D printed bolus can negatively impact the dose delivered to the scalp surface during scalp irradiation. The purpose of this retrospective case study was to implement the use of a 3D milled rigid bolus technique combined with volumetric modulated arc therapy (VMAT) treatment planning and evaluate the dosimetric efficacy in delivering dose to the surface of the scalp. The 8-patient retrospective case study consisted of patients with a scalp lesion treated using a 3D milled bolus, VMAT, 6 megavoltage (MV) photon beams, and aligned for treatment using daily conebeam computed tomography (CT) and 6° of freedom couch positioning. Dose volume histograms (DVHs) were used to evaluate maximum dose delivered to the planning target volumes (PTVs) while the dose homogeneity index (DHI) was calculated and compared to that of an ideal value of 1. The researchers evaluated the minimum dose delivered to the individual PTVs after plan normalization. The researchers found that the 3D milled bolus coupled with volumetric modulated arc therapy increased surface dose homogeneity, while also increasing the percentage of planning target volumes receiving full prescription dose. With statistically significant results, patient specific 3D milled rigid bolus offers a viable bolus option for treatment of superficial scalp lesions when combined with volumetric modulated arc therapy treatment planning. However, a larger sample size used in a scientific research study across multiple institutions would be desirable to validate these case study findings.

Purpose To understand how verification computed tomography-quality assurance (CT-QA) scans influenced clinical decision-making to replan patients with head and neck cancer and identify predictors for replanning to guide intensity-modulated proton therapy (IMPT) clinical practice. Patients and Methods We performed a quality-improvement study by prospectively collecting data on 160 consecutive patients with head and neck cancer treated using spot-scanning IMPT who underwent weekly verification CT-QA scans. Kaplan-Meier estimates were used to determine the cumulative probability of a replan by week. Predictors for replanning were determined with univariate (UVA) and multivariate (MVA) Cox model hazard ratios (HRs). Logistic regression was used to determine odds ratios (ORs). P Results Of the 160 patients, 79 (49.4%) had verification CT-QA scans, which prompted a replan. The cumulative probability of a replan by week 1 was 13.7% (95% confidence interval [CI], 8.82-18.9), week 2, 25.0% (95% CI, 18.0-31.4), week 3, 33.1% (95% CI, 25.4-40.0), week 4, 45.6% (95% CI, 37.3-52.8), and week 5 and 6, 49.4% (95% CI, 41.0-56.6). Predictors for replanning were sinonasal disease site (UVA: HR, 1.82, P = .04; MVA: HR, 3.64, P = .03), advanced stage disease (UVA: HR, 4.68, P 60 Gy equivalent (GyE; relative biologic effectiveness, 1.1) (UVA: HR, 1.99, P Conclusions Weekly verification CT-QA scans frequently influenced clinical decision-making to replan. Additional studies that evaluate the practice of monitoring IMPT-treated patients with weekly CT-QA scans and whether that improves clinical outcomes are warranted.

Purpose Electrocardiogram-gated computed tomography with coronary angiography can be used for cardiac substructure sparing (CSS) optimization, which identifies and improves avoidance of cardiac substructures when treating with intensity modulated radiotherapy (IMRT). We investigated whether intensity modulated proton therapy (IMPT) would further reduce dose to cardiac substructures for patients with mediastinal lymphoma. Patients and Methods Twenty-one patients with mediastinal lymphoma were enrolled and underwent electrocardiogram-gated computed tomography angiography during or shortly after simulation for radiotherapy planning. Thirteen patients with delineated cardiac substructures underwent comparative planning with both IMPT and IMRT. Plans were normalized for equivalent (95%) target volume coverage for treatment comparison. Results Thirteen patients met criteria for this study. The median size of the mediastinal lymphadenopathy was 7.9 cm at the greatest diameter. Compared with IMRT-CSS, IMPT-CSS significantly reduced mean dose to all cardiac substructures, including 3 coronary arteries and 4 cardiac valves. Use of IMPT significantly reduced average whole-heart dose from 9.6 to 4.9 Gy (P Conclusions For patients with mediastinal lymphoma, IMPT-CSS treatment planning significantly reduced radiation dose to cardiac substructures. The significant improvements outlined in this study for proton therapy suggest possible clinical improvement in alignment with previous analyses of CSS optimization.

Decreasing radiotoxicity to the heart, lungs, and contralateral breast has proven to lower the risk of secondary malignancy and improve overall outcomes when treating chest wall (CW) and regional lymph nodes in postmastectomy breast cancer patients. In this retrospective study, 11 postmastectomy patients were selected and planned with a novel hybrid treatment method and a traditional volumetric arc therapy (VMAT) approach for comparison. This hybrid technique was able to optimize tangential beams to minimize heart dose and the VMAT contribution to improve dose conformity around the planning target volume (PTV). Overall, this hybrid technique produced more homogenous target dose coverage and demonstrated a decrease of integral dose to organs at risk (OAR), while the VMAT technique demonstrated a higher affinity for maintaining dose conformity. Further observation of dose distributions also revealed that the hybrid plans were more effective in sparing low-dose spread to healthy tissue in both right- and left-sided cases. This observation was made evident by the reduction in heart V5 and Dmean, decreases in all parameters regarding the contralateral lung, as well as all values other than the V20 of the ipsilateral lung. This unique hybrid planning technique could present an alternative to standard intensity-modulated radiation therapy (IMRT) planning when treating postmastectomy CW and regional lymph nodes, as it has shown the capacity to decrease cardiac, lung, and contralateral breast toxicity while maintaining quality PTV coverage.

The purpose of this study was to investigate the dosimetric impact of weight loss in head and neck (H&N) patients and examine the effectiveness of adaptive planning. Data was collected from 22 H&N cancer patients who experienced weight loss during their course of radiotherapy. The robustness of Intensity Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) treatment plans were compared including the potential need for replanning. The dosimetric impact of weight loss was evaluated by calculating a verification plan for each patient on an assessment CT scan taken during the course of treatment. Using a regression analysis, significance was tested for the dosimetric change in target volumes and 10 specific organs at risk (OAR) using an anatomical separation difference in the H&N at corresponding levels. For both the IMRT and VMAT plans, a significant correlation was found for the dose to 5% of the high risk Planning Target Volume (PTV) (D5), dose to 95% of the intermediate risk PTV and Clinical Target Volume (CTV) (D95), and the percentage of the pharynx receiving 65 Gy. An independent t-test was also performed for each metric in the VMAT and IMRT plans showing the dose to 95% of the intermediate risk PTV as significant. No quantitative method for finding the threshold of anatomical separation difference requiring a replan was established. Based on the increase in dose to organs at risk and increased target coverage due to separation loss, it was concluded that adaptive radiotherapy may not always be necessary when alignment of bony anatomy and remaining soft tissue is within tolerance. Physician judgment and preference is needed in such situations.

The head and neck (H&N) region is frequently replanned during intensity-modulated proton therapy (IMPT), but replanning disrupts clinical workflow and presents additional burden on patients. The purpose of this study was to establish a standard treatment planning approach to minimize H&N replanning by identifying a correlation between dosimetric variables and replan frequency. In a retrospective study of 27 bilateral oropharyngeal cancer patients treated with IMPT at a single institution, cases were evaluated using Fisher's exact tests and logistic regression for a significant relationship between replan frequency and the following variables: beam number, clinical target volume (CTV) coverage, presence of dental fillings, and robustness. The reason and timing for replan initiation, and patient immobilization was also recorded to identify trends. Results suggested that beam number, CTV coverage, presence of dental fillings, and the initial robustness curve on the high-dose CTV did not individually contribute to replanning frequency. Setup variation in the soft tissue of the neck was the most prominent reason for replanning. A lack of correlation between the number of replans and the studied dosimetric variables highlights the necessity of verification CT and adaptive replanning in IMPT of H&N cancer. Departments may therefore benefit from a methodical replan workflow. One development showing potential to enhance clinical replan processes is machine learning-based automatic adaptive replanning.

Radiotherapy to an intact breast was previously determined to have a positive correlation between breast separation measurement and hot spot dose. As breast separation measurement increased, hot spot dose increased. The purpose of this retrospective study was to determine if this correlation persisted despite current techniques including field-in-field (FiF) blocking and mixed photon energies. Radiation treatment plans on unilateral intact breasts from 90 female, early stage breast cancer patients treated with lumpectomy were analyzed. Plans were created using 3-dimensional conformal radiation therapy (3D-CRT) nondivergent opposing tangent beams, FiF technique, and 6 MV with or without higher energy photons. Data collected included breast separation measurement, hot spot point dose and location, number of beams, photon energy, clinical target volume (CTV) coverage and breast volume coverage. Correlations between breast separation measurement and each of these values were determined. The positive correlation between breast separation measurement and hot spot dose persisted despite incorporating FiF and mixed photon energies. Correlations were also found between breast separation and the number of beams as well as breast separation and photon energy. Larger breast separations tended to be treated with additional beams of higher photon energy. There were no correlations found between breast separation and CTV or breast volume coverage. The data in this study suggested the medical dosimetrist should expect hot spots above prescription dose of 106%, 107%, and 108% for small, medium and large breast separation sizes respectively. Additionally, adding a high energy photon bean may be indicated with medium and large breast separations.

Applying dual, or mixed photon energies during radiation therapy is a common practice in 3-dimensional conformal radiation therapy (3D-CRT). Mixed photon energies are used to provide uniform dose coverage to a planning target volume (PTV) that ranges in depth from the skin surface. Though the application of mixed photon energies in 3D-CRT was once the convention for treating anal cancers with lymph node involvement (AC-LNI), the advantages offered by volumetric modulated arc therapy (VMAT) prove to be the optimal form of therapy for AC-LNI. Recently, multiple researchers have uncovered benefits in employing multiple photon energies in VMAT planning for prostate cancer. A retrospective study was completed to assess the impact of implementing mixed energy VMAT planning in comparison to conventional single energy VMAT planning for AC-LNI. Data from 20 patients with AC-LNI was collected to analyze the dosimetric effects of mixed energy VMAT treatments in terms of PTV conformity index, PTV homogeneity index, monitor unit usage, and organs at risk sparing. For each patient 3 treatment plans were created: a single energy 6 MV plan, a single energy 10 MV plan, and a mixed 6 MV and 10 MV energy plan. Analysis of the resulting dosimetric outcomes showed statistical significance. The current study concluded that mixed energy VMAT plans have some effect on treating AC-LNI when compared to single energy VMAT plans.

The aim of this retrospective study was to determine if the split x-jaw planning technique could be used with Varian linear accelerators to improve plan conformity and limit dose to organs at risk (OAR) for planning target volumes that require field sizes larger than the 15 cm extent of the multileaf collimator in the x-jaw position. Traditional planning techniques include limited and open x-jaw methods. The study population included 20 randomly selected patients with endometrial carcinoma. Treatment plans for each patient were designed using split, limited, and open x-jaw volumetric modulated arc radiotherapy for comparison purposes. Dose statistics including the PTV conformity index and dose to OAR were used to evaluate plan performance. The split x-jaw planning method had the most consistent conformity index (0.98 ± 0.02), followed by the open (01 ± 0.03), and the limited (1.04 ± 0.05) techniques. On average, the split method better spared the OAR. In comparison to the limited and open techniques, the split method reduced the dose to the bowel by 3.8%, rectum by 3.2%, sigmoid by 2.1%, right femoral head by 3.5%, and left femoral head by 3.9%. The split and open techniques showed comparable bladder results and were superior over the limited method. The monitor units were highest with the split method leading to increased treatment times. The split x-jaw planning technique should be used with Varian linear accelerators to produce superior volumetric modulated arc radiotherapy plans for planning target volumes larger than the maximum extent of the multileaf collimator in the x-jaw direction.

This document reports the design of a retrospective study to validate the clinical acceptability of a deep-learning-based model for the autosegmentation of organs-at-risk (OARs) for use in radiotherapy treatment planning for head & neck (H&N) cancer patients.

This chapter highlights the important lessons about wartime learning. It seeks to know what enabled the marines — masters of conventional maneuver warfare — to adapt to the demands of a decidedly unconventional counterinsurgency doctrine. It also explores why do some militaries learn faster than others and what can we do to ensure that the Marine Corps — and all of our war-fighting organizations — are ready to learn as quickly as possible the next time we send troops into harm's way. The chapter's central premise is that the First World War is uniquely relevant to the challenges that today's leaders face as they prepare for tomorrow's wars. It then shifts to outline at least three reasons why the First World War — and the years leading up to it — is relevant to the challenges military leaders face today. The first reason involves the rate of technological change, the second reason concerns the character of technological change, and the third reason involves the relative absence of great-power wars in recent times. The chapter offers a theory of wartime learning — assessment, command, and training (ACT) theory — to explore how the German Army mastered the elastic defense in depth.

This chapter explains assessment, command, and training (ACT) theory in detail, describing its predictions and the kinds of evidence that confirm or reject its validity. The chapter covers a detailed discussion of definitions, case selection, and scope conditions. ACT theory seeks to explain why some wartime militaries are better than others at learning so as to correctly update how they fight. With such knowledge, the chapter modifies the definitions of learning and doctrine to understand how a specific subset of organizations (militaries) learn while under extraordinary conditions (warfare). It focuses specifically on one type of learning: how militaries update, revise, and otherwise change their war-fighting doctrines. The chapter then explores how learning helps a military force become more effective on the battlefield. It details how the wartime militaries, assessment mechanisms, and centralized training are particularly relevant to both battlefield effectiveness and doctrinal learning.

This book develops a novel theory to explain how wartime militaries learn. It focuses on the Western Front, which witnessed three great-power armies struggle to cope with deadlock throughout the First World War, as the British, French, and German armies all pursued the same solutions-assault tactics, combined-arms, and elastic defense in depth. By the end of the war, only the German army managed to develop and implement a set of revolutionary offensive, defensive, and combined-arms doctrines that in hindsight represented the best way to fight. The book identifies three organizational variables that determine how fighting militaries generate new ideas, distinguish good ones from bad ones, and implement the best of them across the entire organization. These factors are: the degree to which leadership delegates authority on the battlefield; how effectively the organization retains control over soldier and officer training; and whether or not the military possesses an independent doctrinal assessment mechanism. Through careful study of the British, French, and German experiences in the First World War, the book provides a model that shows how a resolute focus on analysis, command, and training can help prepare modern militaries for adapting amidst high-intensity warfare in an age of revolutionary technological change.

This chapter investigates the case of the French Army on the Western Front. It argues that the French Army was arguably the most decentralized and adaptive army on the Western Front. French infantry units experimented sooner and more aggressively than their British and German counterparts. The chapter then analyses the army's assault tactics and elastic defenses, as well as the army's moderately decentralized command and control for most of the war. The chapter also discusses French Army's high command — the Grand Quartier Général (GQG). It recounts how the GQG struggled to isolate, identify, and promote the sort of assault, combined-arms, and defensive tactics needed. The chapter highlights two factors to take into account when testing assessment, command, and training (ACT) theory against the French Army. First, political and strategic imperatives limited the army's doctrinal options. Second, is that the French Army occupies a blind spot in the English-language military historiography on tactical change during the First World War.

This chapter reviews three confounding factors and alternative ways to explain events. It begins with analyzing Germany's experience during the First World War and their inept political and strategic decisions. The chapter also explores the author's assumption that the British, French, and German armies should have converged on a superior war-fighting doctrine that combined flexible assault tactics, integrated artillery–infantry operations, and elastic defenses in depth. Genius and individual leadership offer yet another tempting way to account for change. The chapter unfolds the story of wartime learning during the First World War. It introduces two shadow cases — the US Army in Vietnam (1965–1973) and Iraq (2003–2010) — so as to suggest that assessment, command, and training (ACT) theory can explain more than just learning on the Western Front. The chapter concludes by identifying important policy implications for contemporary defense strategists.

This chapter highlights the German Army's experience on the Western Front. It shows that the German Army learned more effectively as it shifted toward moderately decentralized command practices, developed coherent and independent assessment mechanisms, and exerted centralized control over training. The Germans were the first to reach this ideal setup and were also the first to adopt (most of) the elements of a superior combined-arms doctrine. The chapter also illustrates the way organizational structure influences learning. It argues that the German Army was structured to learn. Its often-cited command practices were part of the story, but its assessment mechanisms and highly centralized training systems were also important. The chapter reveals that the German Army was not more creative or original than its competitors. It was, however, better at turning good concepts into practical doctrine. Ultimately, the chapter examines the importance of tactical performance in the military effectiveness equation, and how the German Army learned faster than its adversaries.

This chapter provides a basic overview of the tactical dilemma facing the British, French, and German armies on the Western Front. It investigates how the troop-to-space ratio and the imbalance between strategic and tactical mobility — combined with firepower contributed to the stalemate on the Western Front. Beyond these daunting firepower and organizational challenges, the chapter also looks at a number of coordination problems being faced by the commanders during the war: infantry–artillery coordination, the challenge around achieving surprise, and logistics. It also examines the two unenviable trade-offs encountered by the commanders which revolved around depth and breadth. The chapter then shifts to discuss the challenges of the defenders and how they had to constantly adapt during the war. It identifies the optimal doctrine for ending the stalemate. Finally, the chapter analyzes the British, French, and German armies' set of solutions to these problems and challenges: assault tactics, combined-arms, and elastic defense in depth.

This chapter begins with the British Expeditionary Force's (BEF) experience with doctrinal learning. It analyses how the prewar British Army practiced moderately centralized command and control. The BEF increased control over tactics and operations from early 1915 until at least mid-1916. The BEF also lacked a doctrinal assessment mechanism for the first half of the war and maintained a loose grip over training. The chapter then shifts to discuss the establishment of a formal assessment mechanism, called the Training Branch, in February 1917. It explores how the BEF's command practices, assessment mechanism, and training systems changed over the course of the war. Ultimately, this chapter looks at a causal link that existed between the British Army's organizational structure and practices and its ability to learn. The chapter then investigates how the Training Branch enabled the BEF to systematically capture, test, analyze, and disseminate new ideas.

Background/aim Glioblastoma, also known as glioblastoma multiforme (GBM), is the most aggressive type of primary brain tumor and a cornerstone in its treatment is radiotherapy (RT). However, RT for GBM is largely ineffective at clinically safe doses, thus, the study of radiosensitizers is of great significance. Materials and methods With accumulating evidence for the anticancer effect of compounds from cranberry, this study was designed to investigate if cranberry extract (CE) sensitizes GBM to RT in the widely used human glioblastoma cell line U87. We utilized clonogenic survival assays, cell proliferation assays, and caspase-3 activity kits. Potential proliferative and apoptotic molecular mechanisms were evaluated by reverse transcription-polymerase chain reaction. Results We found that CE alone had little effect on the survival of U87 cells. However, RT supplemented by CE significantly inhibited proliferation and promoted apoptosis of U87 cells when compared with RT alone. The proliferation-inhibitory effect of RT/CE might be attributable to the up-regulation of p21, along with the down-regulation of cyclin B and cyclin-dependent kinase 4. This pro-apoptotic effect might additionally be attributable to the down-regulation of survivin. Conclusion These results warrant further study of the potential radiosensitizing capacity of CE in glioblastoma and other cancer types.

The purpose of this case study is to develop a method to account for the difference in the daily volumes in the bladder, rectum, and targets in prostate radiotherapy and to compare the predicted dose to the actual dose to these organs. Five patients, both prospectively and retrospectively, were selected from 2 different cancer centers, with a biopsy-confirmed diagnosis of prostate cancer. The patients' planning target volume (PTV) and organs at risk (OAR) were contoured on the computed tomography (CT) dataset using either Eclipse or Monaco treatment planning systems (TPSs). Cone-beam computed tomography (CBCT) scans were collected before each daily treatment and exported to MIM software for analysis. The automatically generated reports evaluated the organ volume changes, the actual dose received during a single fraction, and the projected dose to each organ at the completion of the treatment course via comparative cumulative dose-volume histograms (DVHs). Volume changes in the bladder and rectum can cause notable variations in the prescribed dose vs the actual dose received. MIM software was proven to have utility prospectively by tabulating daily dose and projecting final doses, potentially aiding physicians in decisions about the boost plans, thus making offline adaptive radiation therapy (ART) clinically manageable.

The aim of this study is to determine if RapidPlan (RP) can be used as a prediction method to determine which left-sided supine breast cancer patients would benefit from the deep inspiration breath-hold (DIBH) technique. An RP model database was created with 72 clinically approved 3D conformal radiation therapy (3D-CRT) treatment plans. This model was validated by introducing 10 new patient data sets, creating RP-generated plans and comparing the clinically approved plan for the corresponding patient. The prediction ability of the model was then tested on the free-breathing (FB) scans of patients with clinically approved DIBH plans totaling 29 patients and results were then compared to the FB clinical plan attempts. A statistical analysis performed on the data indicated a strong correlation for the mean heart dose (R2 = 0.914; p-value