scholarly journals RADI-15. CLUSTERING AND GROUPING OF BRAIN METS IN RADIOSURGERY TREATMENTS

2019 ◽  
Vol 1 (Supplement_1) ◽  
pp. i24-i24
Author(s):  
Khaled Salah ◽  
John Mckenna ◽  
Gabor Jozsef ◽  
Jonathan Knisely
Keyword(s):  
Maximum Dose ◽  
Treatment Plan ◽  
Normal Brain ◽  
Dose Distributions ◽  
Treatment Plans ◽  
Prescription Dose ◽  
Clustering Approach ◽  
Centers Of Mass ◽  
Dose Volumes ◽  
Single Isocenter

Abstract INTRODUCTION: Radiosurgical treatment of numerous lesions in the brain with ‘single-isocenter’ radiosurgery on a linac often requires using multiple isocenters. With our TPS (Elements, Brainlab) multiple plans need to be generated for each set of lesions, and a sum plan calculated. We investigated how to distribute multiple lesions into two groups for two isocenters to achieve a good summed dose distribution. METHODS: The DICOM RS file is exported and the PTV data is extracted by a MATLAB program that calculates the convex hulls, estimated radii, and the centers of mass for each PTV. Two approaches were tried: (1) Lesions close to each other (closer than a certain limit) are put in different groups and (2) Create clusters by kMeans clustering, which allows close lesions but the groups are distant from each other. MATLAB programs were written for all approaches. Treatment plans were generated for three patients (20, 13, 15 lesions) using each method and compared with the actual treatment plan used to treat the patient based on the intuitive grouping of lesions by the planners. Dose maximums outside the lesions, and volumes in the normal tissue exceeding 75, 50 and 25% of the prescription dose were evaluated. RESULTS AND DISCUSSION: The coverage of all lesions for all plans were 95% of the prescription dose. The first approach allowed lowering the maximum dose between lesions, but with summing dose distributions this advantage disappeared. The maximum dose and the 75, 50 and 25% dose volumes were also all worse than in plans generated by experienced planners and higher normal brain doses are delivered if closely spaced lesions are separated into different isocenters for treatment. However, the clustering approach resulted in the same or better values of these same parameters, i.e. improved dose distributions over the dosimetrist’s intuitively chosen separation.

scholarly journals PS1 - 189 A Universal Predictive Model for Dose Fall-Off in MLC-Based Stereotactic Brain Radiosurgery

2016 ◽  
Vol 43 (S4) ◽  
pp. S8-S8
Author(s):  
M. Ruschin ◽  
A. Sahgal ◽  
H. Soliman ◽  
B. Chugh ◽  
S. Myrehaug ◽  
...  
Keyword(s):  
Clinical Decision Making ◽  
Treatment Plan ◽  
Clinical Decision ◽  
Target Volume ◽  
Adjustment Factor ◽  
Ongoing Work ◽  
Toxicity Risk ◽  
Treatment Plans ◽  
Prescription Dose ◽  
Prediction Band

Predictive modeling of dose fall-off in radiosurgery could assist in clinical decision-making when prescribing a treatment plan with minimized toxicity risk. The purpose of this study is to develop a predictive dose fall-off model. Materials/Methods: We retrospectively reviewed treatment plans from 257 patients (365 lesions) with total doses ranging from 20 to 35Gy in 5 fractions. For each plan, we measured both total volume of the external contour (EXT) and BrainMinusPTV (BMP) receiving P=20% to P=80% of the prescription dose. The model has form y=Fa(PTV)b+/-delta. y=volume of EXT or BMP (cc’s); a and b are curve-fitting coefficients; PTV=total planning target volume (cc’s); F is an adjustment factor (>1) to account for number of targets; delta is the 95% prediction band. F, a, b, and delta were modeled such that dose-fall can be forecast for any PTV and dose level. Results: The model coefficients were as follows: Coefficient EXT BMP a 19927(100×P)exp(-2) 17122(100×P)exp(-2) b 0.42(100×P)exp(0.17) 0.63 F -0.0156×(100×P)+2.5517 delta 384467×(100×P)exp(-2.3159) The table can be used to determine the model for any P from 20% to 80%. Example: the EXT receiving 50%, P=0.5, a=8.0, b=0.82, F=1.8, delta=45. Thus, EXT-50=8(PTV0.82) or 1.8×8(PTV0.82) for 1-3 or >3 targets, respectively,+/-45cc’s. The model was verified against published values of dose fall-off from linacs. Conclusion: A predictive dose fall-off model was generated for linac-based radiosurgery. The model can be used for quality assurance or for inter-institutional comparisons. Ongoing work is being conducted to extend the model to a SRS cones system.

scholarly journals Longitudinal Grouping of Target Volumes for Volumetric-Modulated Arc Therapy of Multiple Brain Metastases

2021 ◽  
Vol 11 ◽  
Author(s):  
Yingjie Xu ◽  
Junjie Miao ◽  
Qingfeng Liu ◽  
Peng Huang ◽  
Pan Ma ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Brain Tissue ◽  
Volumetric Modulated Arc Therapy ◽  
Target Volume ◽  
Normal Brain ◽  
Normal Brain Tissue ◽  
Arc Therapy ◽  
Target Volumes ◽  
Prescription Dose ◽  
Single Isocenter

PurposeTreatment of multiple brain metastases with single-isocenter volumetric modulated arc therapy causes unnecessary exposure to normal brain tissue. In this study, a longitudinal grouping method was developed to reduce such unnecessary exposure.Materials and MethodsThis method has two main aspects: grouping brain lesions longitudinally according to their longitudinal projection positions in beam’s eye view, and rotating the collimator to 90° to make the multiple leaf collimator leaves conform to the targets longitudinally group by group. For 11 patients with multiple (5–30) brain metastases, two single-isocenter volumetric modulated arc therapy plans were generated using a longitudinal grouping strategy (LGS) and the conventional strategy (CVS). The prescription dose was 52 Gy for 13 fractions. Dose normalization to 100% of the prescription dose in 95% of the planning target volume was adopted. For plan quality comparison, Paddick conformity and the gradient index of the planning target volume, and the mean dose, the V100%, V50%, V25%, and V10% volumes of normal brain tissue were calculated.ResultsThere were no significant differences between the LGS and CVS plans in Paddick conformity (p = 0.374) and the gradient index (p = 0.182) of the combined planning target volumes or for V100% (p = 0.266) and V50% (p = 0.155) of the normal brain. However, the V25% and V10% of the normal brain which represented the low-dose region were significantly reduced in the LGS plans (p = 0.004 and p = 0.003, respectively). Consistently, the mean dose of the entire normal brain was 12.04 and 11.17 Gy in the CVS and LGS plans, respectively, a significant reduction in the LGS plans (p = 0.003).ConclusionsThe longitudinal grouping method can decrease unnecessary exposure and reduces the low-dose range in normal brain tissue.

CyberKnife radiosurgery for trigeminal neuralgia: unanticipated iatrogenic effect following successful treatment

2011 ◽  
Vol 115 (5) ◽  
pp. 940-944 ◽  
Author(s):  
Anuj V. Peddada ◽  
D. James Sceats ◽  
Gerald A. White ◽  
Gyongyver Bulz ◽  
Greg L. Gibbs ◽  
...  
Keyword(s):  
Case Report ◽  
Trigeminal Neuralgia ◽  
Stereotactic Radiosurgery ◽  
Oral Mucositis ◽  
Maximum Dose ◽  
Treatment Plan ◽  
Cyberknife Radiosurgery ◽  
Prescription Dose ◽  
Entire Treatment ◽  
Iatrogenic Effect

This case report of 74-year-old man with trigeminal neuralgia is presented to underscore the importance of evaluating the entire treatment plan, especially when delivering large doses where even a low percentage of the prescription dose can contribute a substantial dose to an unintended target. The patient was treated using the CyberKnife stereotactic radiosurgery system utilizing a nonisocentric beam treatment plan with a 5-mm fixed collimator generating 111 beams to deliver 6000 cGy to the 79% isodose line with a maximum dose of 7594 cGy to the target. Two weeks after treatment the patient's trigeminal neuralgia symptoms resolved; however, the patient developed oral mucositis due to the treatment. This case report reviews the cause of mucositis and makes recommendations on how to prevent unintended targets from receiving treatment.

scholarly journals The effects of a preoperative multidisciplinary conference on outcomes for high-risk patients with challenging surgical treatment options: a retrospective study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Masayoshi Koike ◽  
Mie Yoshimura ◽  
Yasushi Mio ◽  
Shoichi Uezono
Keyword(s):  
Patient Safety ◽  
Retrospective Study ◽  
High Risk ◽  
Treatment Plan ◽  
Treatment Options ◽  
High Risk Patients ◽  
Appropriate Treatment ◽  
Risk Patients ◽  
Treatment Plans ◽  
Multidisciplinary Conference

Abstract Background Surgical options for patients vary with age and comorbidities, advances in medical technology and patients’ wishes. This complexity can make it difficult for surgeons to determine appropriate treatment plans independently. At our institution, final decisions regarding treatment for patients are made at multidisciplinary meetings, termed High-Risk Conferences, led by the Patient Safety Committee. Methods In this retrospective study, we assessed the reasons for convening High-Risk Conferences, the final decisions made and treatment outcomes using conference records and patient medical records for conferences conducted at our institution from April 2010 to March 2018. Results A total of 410 High-Risk Conferences were conducted for 406 patients during the study period. The department with the most conferences was cardiovascular surgery (24%), and the reasons for convening conferences included the presence of severe comorbidities (51%), highly difficult surgeries (41%) and nonmedical/personal issues (8%). Treatment changes were made for 49 patients (12%), including surgical modifications for 20 patients and surgery cancellation for 29. The most common surgical modification was procedure reduction (16 patients); 4 deaths were reported. Follow-up was available for 21 patients for whom surgery was cancelled, with 11 deaths reported. Conclusions Given that some change to the treatment plan was made for 12% of the patients discussed at the High-Risk Conferences, we conclude that participants of these conferences did not always agree with the original surgical plan and that the multidisciplinary decision-making process of the conferences served to allow for modifications. Many of the modifications involved reductions in procedures to reflect a more conservative approach, which might have decreased perioperative mortality and the incidence of complications as well as unnecessary surgeries. High-risk patients have complex issues, and it is difficult to verify statistically whether outcomes are associated with changes in course of treatment. Nevertheless, these conferences might be useful from a patient safety perspective and minimize the potential for legal disputes.

scholarly journals Multicriterial CNN based beam generation for robotic radiosurgery of the prostate

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Stefan Gerlach ◽  
Christoph Fürweger ◽  
Theresa Hofmann ◽  
Alexander Schlaefer
Keyword(s):  
Deep Learning ◽  
Treatment Planning ◽  
Treatment Plan ◽  
Plan Quality ◽  
New Approach ◽  
Beam Generation ◽  
Radiological Features ◽  
Improve Treatment ◽  
Robotic Radiosurgery ◽  
Treatment Plans

AbstractAlthough robotic radiosurgery offers a flexible arrangement of treatment beams, generating treatment plans is computationally challenging and a time consuming process for the planner. Furthermore, different clinical goals have to be considered during planning and generally different sets of beams correspond to different clinical goals. Typically, candidate beams sampled from a randomized heuristic form the basis for treatment planning. We propose a new approach to generate candidate beams based on deep learning using radiological features as well as the desired constraints. We demonstrate that candidate beams generated for specific clinical goals can improve treatment plan quality. Furthermore, we compare two approaches to include information about constraints in the prediction. Our results show that CNN generated beams can improve treatment plan quality for different clinical goals, increasing coverage from 91.2 to 96.8% for 3,000 candidate beams on average. When including the clinical goal in the training, coverage is improved by 1.1% points.

scholarly journals Outcomes of Peer Review for Radiotherapy Treatment Plans With Palliative Intent

2018 ◽  
Vol 14 (12) ◽  
pp. e794-e800
Author(s):  
Dina Thompson ◽  
Kimberly Cox ◽  
James Loudon ◽  
Ivan Yeung ◽  
Woodrow Wells
Keyword(s):  
Peer Review ◽  
Treatment Plan ◽  
Palliative Radiotherapy ◽  
Cancer Center ◽  
Palliative Intent ◽  
Treatment Plans ◽  
Important Quality ◽  
Radiation Medicine ◽  
Radiotherapy Treatment

Purpose: Peer review of a proposed treatment plan is increasingly recognized as an important quality activity in radiation medicine. Although peer review has been emphasized in the curative setting, applying peer review for treatment plans that have palliative intent is receiving increased attention. This study reports peer review outcomes for a regional cancer center that applied routine interprofessional peer review as a standard practice for palliative radiotherapy. Methods and Materials: Peer review outcomes for palliative radiotherapy plans were recorded prospectively for patients who began radiotherapy between October 1, 2015, and September 30, 2017. Recommended and implemented changes were recorded. The content of detailed discussions was recorded to gain insight into the complexities of palliative treatment plans considered during peer review. Results: Peer review outcomes were reviewed for 1,413 treatment plans with palliative intent. The proportions of detailed discussions and changes recommended were found to be 139 (9.8%) and 29 (2.1%), respectively. The content of detailed discussions and changes recommended was categorized. Major changes represented 75.9% of recommended changes, of which 84.2% were implemented clinically. Conclusion: Many complexities exist that are specific to palliative radiotherapy. Interprofessional peer review provides a forum for these complexities to be openly discussed and is an important activity to optimize the quality of care for patients with treatment plans that have palliative intent.

Willingness to Travel for Cellular Therapy: The Influence of Follow-Up Care Location, Oncologist Continuity, and Race

2021 ◽  
pp. OP.21.00312
Author(s):  
Zachary A. K. Frosch ◽  
Esin C. Namoglu ◽  
Nandita Mitra ◽  
Daniel J. Landsburg ◽  
Sunita D. Nasta ◽  
...  
Keyword(s):  
Travel Time ◽  
Cellular Therapy ◽  
Treatment Plan ◽  
Admission Rate ◽  
B Cell Lymphoma ◽  
Travel Times ◽  
Importance Weights ◽  
Follow Up Care ◽  
Treatment Plans

PURPOSE Patients weigh competing priorities when deciding whether to travel to a cellular therapy center for treatment. We conducted a choice-based conjoint analysis to determine the relative value they place on clinical factors, oncologist continuity, and travel time under different post-treatment follow-up arrangements. We also evaluated for differences in preferences by sociodemographic factors. METHODS We administered a survey in which patients with diffuse large B-cell lymphoma selected treatment plans between pairs of hypothetical options that varied in travel time, follow-up arrangement, oncologist continuity, 2-year overall survival, and intensive care unit admission rate. We determined importance weights (which represent attributes' value to participants) using generalized estimating equations. RESULTS Three hundred and two patients (62%) responded. When all follow-up care was at the center providing treatment, plans requiring longer travel times were less attractive ( v 30 minutes, importance weights [95% CI] of –0.54 [–0.80 to –0.27], –0.57 [–0.84 to –0.29], and –0.17 [–0.49 to 0.14] for 60, 90, and 120 minutes). However, the negative impact of travel on treatment plan choice was mitigated by offering shared follow-up (importance weights [95% CI] of 0.63 [0.33 to 0.93], 0.32 [0.08 to 0.57], and 0.26 [0.04 to 0.47] at 60, 90, and 120 minutes). Black participants were less likely to choose plans requiring longer travel, regardless of follow-up arrangement, as indicated by lower value importance weights for longer travel times. CONCLUSION Reducing travel burden through shared follow-up may increase patients' willingness to travel to receive cellular therapies, but additional measures are required to facilitate equitable access.

scholarly journals A Creature Called CIH: From a Quantum Explanation of Psychological Disorders to a Classical Limit of Behavior

2017 ◽  
Author(s):  
Saeideh Mohseni Nezhad
Keyword(s):  
Impulse Control ◽  
Classical Limit ◽  
Treatment Plan ◽  
Psychological Disorders ◽  
Conduct Disorders ◽  
Quantum Limit ◽  
Quantum Model ◽  
Quantum Field Theories ◽  
Treatment Plans ◽  
Suitable Treatment

The objective of this study is to present a Quantum Model for designing and predicting suitable treatment plans for different psychological disorders. The theory has been extracted from Quantum Field Theories and is modeled on a Conceptual Isolated Human (CIH), which is a totally abstract idea. The Quantum limit of the model explains the way disorders are formed, and its classical limit forecasts the observable CIH behavior. Then, a pattern has been presented for treatment plans based on the CIH Quantum Model, which is named ‘Systematic Balancing’. Finally, Systematic Balancing is presented in this article in order to explain and predict the treatment plan for the category of 'Disruptive, Impulse-Control, and Conduct Disorders in DSM-5'.

scholarly journals Assessment of the capacity of future Dentists to elaborate treatment plans for dental trauma

2020 ◽  
Vol 9 (8) ◽  
pp. e255985718
Author(s):  
Daniela Atili Brandini ◽  
Denise Pedrini ◽  
Caio Vinicius Lourenço Debortoli ◽  
Luiza Monzoli Côvre ◽  
Marina Fuzette Amaral
Keyword(s):  
Treatment Plan ◽  
Dental Trauma ◽  
Great Difficulty ◽  
Cross Sectional ◽  
Adequate Treatment ◽  
Root Fracture ◽  
Occlusal Adjustment ◽  
Treatment Plans ◽  
Dentoalveolar Trauma ◽  
Systemic Condition

The prognosis of dental trauma depends on professionals with solid and updated knowledge. The objective was to evaluate the ability of undergraduate dentistry students to develop treatment plans for dental trauma. This cross-sectional, observational, quantitative  study had a sample of 242 participants. A clinical case involving avulsion of tooth 11 and complex coronary root fracture of tooth 21 was selected. All data relating to the patient's exams were added to a clinical record, which was delivered to students in the final year of the undergraduate dentistry course for three years consecutive. The students were instructed to develop a treatment plan for this case. The factors most considered in avulsion treatment plans were: how, when and where the trauma occurred, the patient's age and systemic condition. Of the students, 39.7% developed an adequate treatment plan, the main mistake being the lack of occlusal adjustment. In addition, 9,9% of students had an adequate treatment plan for coronary artery fracture. The recovery of periodontal biological space and the indication of intraradicular retainers were the main difficulties. It is concluded that undergraduate dentistry students had great difficulty in formulating treatment plans suitable for more severe cases of dentoalveolar trauma involving several specialties.

scholarly journals Transition from conformal to advanced radiotherapy techniques in treatment planning of gynecological cancer patients

2021 ◽  
pp. 77-77
Author(s):  
Borislava Petrovic ◽  
Olivera Ivanov ◽  
Milana Marjanovic ◽  
Jelena Licina ◽  
Ivan Gencel ◽  
...  
Keyword(s):  
At Risk ◽  
Cancer Patients ◽  
Maximum Dose ◽  
Organs At Risk ◽  
Gynecological Cancer ◽  
Conformal Radiation Therapy ◽  
Significant Difference ◽  
Treatment Plans ◽  
Radiation Induced ◽  
Risk Treatment

Background/ Aim. Transition from standard to highly conformal radiation therapy techniques, requires implementation of complex advanced dosimetry. The aim of the work was comparison of dosimetric parameters of 3DCRT and VMAT plan, as well as complications after treatment in relation to dosimetric parameters at gynecological cancer patients. Methods. Forty-nine gynecological cancer patients were included in the study. All patients were planned for 3D CRT, but due to unacceptable doses to organs at risk, treatment plans for IMRT or VMAT were generated for 21 patients. The patients were prescribed 50.4 Gy/28 fractions (4) and 45 Gy/25 fractions (45 patients). The coverage of PTV and doses to organs at risk were recorded. PTV margins were evaluated for both techniques according to the Van Herk formula. Results. ICRU 83 criteria were fulfilled in all 3DCRT /VMAT/IMRT plans providing optimal coverage of PTV. Doses to OARS: in average, the V45Gy in small bowel in IMRT/VMAT plans was four times smaller than the same of 3DCRT plans. The V45Gy of small bowels was in average 49.4cm3 in IMRT/VMAT plans, while in 3DCRT plans it was 211.6 cm3. In case of femoral head, significant reduction in V30Gy (10.8 % vs. 33.1%) and mean dose in case of IMRT/VMAT plans was recorded (30.4 Gy in 3DCRT vs 23.6 Gy). Rectum was planned with significantly lower dose in terms of V30Gy (79.5% vs 95.2%) in IMRT/VMAT plans. Bladder was better spared in VMAT plans in terms of V40Gy (51% vs. 91%), but maximum dose was higher in VMAT plans than in 3DCRT (50.1 Gy to 48.1 Gy in average). For all OARs there is statistically significant difference registered at p>0.05. Toxicities recorded in VMAT and 3DCRT patients include mainly radiation induced cystitis and enteritis. Patients treated with 3DCRT generally have longer recovery time. Homogeneity index was 0.11 for VMAT plans and 0.09 for 3DCRT plans. Conclusions. Analysis of dosimetric parameters revealed significant differences in normal tissue doses for same 3DCRT and VMAT patient, which confirmed necessity for implementation of advanced techniques for as many patients as possible.

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