Fraction-variant beam orientation optimization for non-coplanar IMRT.

Fraction-variant beam orientation optimization for non-coplanar IMRT. Phys Med Biol. 2018 Jan 19;: Authors: O'Connor D, Yu V, Nguyen D, Ruan D, Sheng K Abstract Conventional beam orientation optimization (BOO) algorithms for IMRT assume that the same set of beam angles is used for all treatment fractions. In this paper we present a BOO formulation based on group sparsity that simultaneously optimizes non-coplanar beam angles for all fractions, yielding a fraction-variant (FV) treatment plan. Beam angles are selected by solving a multi-fraction fluence map optimization problem involving 500-700 candidate beams per fraction, with an additional group sparsity term that encourages most candidate beams to be inactive. The optimization problem is solved using the Fast Iterative Shrinkage-Thresholding Algorithm. Our FV BOO algorithm is used to create five-fraction treatment plans for digital phantom, prostate, and lung cases as well as a 30-fraction plan for a head and neck case. A homogeneous PTV dose coverage is maintained in all fractions. The treatment plans are compared with fraction-invariant plans that use a fixed set of beam angles for all fractions. The FV plans reduced OAR mean dose and D2 values on average by 3.3% and 3.8% of the prescription dose, respectively. Notably, mean OAR dose was reduced by 14.3% of prescription dose (rectum), 11.6% (penile bulb), 10.7% (seminal vesicle), 5.5% (right femur), 3.5% (bladder), 4.0% (normal left lung), 15.5% (co...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research

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ConclusionFor planners A and B, the usage of PlanIQ did not show a great improvement in the sparing of organs-at-risk whereas for planner C it made a major difference. In any case, PlanIQ contributed to a lower plan quality output variability among the different planners.
Source: Radiation Physics and Chemistry - Category: Physics Source Type: research
Abstract Recent availability of MRI-guided linear accelerators has introduced a number of clinical challenges, particularly in the context of online plan adaptation. Paramount among these is verification of plan quality prior to patient treatment. Currently, there are no commercial products available for monitor unit verification that fully support the newly FDA cleared Elekta Unity 1.5 T MRI-linac. In this work, we investigate the accuracy and precision of RadCalc for this purpose, which is a software package that uses a Clarkson integration algorithm for point dose calculation. To this end, 18 IMRT patient ...
Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research
AbstractProstate cancer is the most common cancer among men in the USA. Interestingly, recent studies suggest that patients with inflammatory bowel disease (IBD) are at increased risk of developing prostate cancer. Importantly, patients with IBD who develop prostate cancer require thoughtful care when using immunosuppressants to treat the IBD in the setting of malignancy. Further, consideration must be given to the proximity of the prostate to the gastrointestinal tract when treating with radiation where there is concern for the effects of inadvertent exposure of radiation to the diseased bowel. In general, management of i...
Source: Digestive Diseases and Sciences - Category: Gastroenterology Source Type: research
CONCLUSION: RT comprises an effective treatment modality of benign brain and intracranial lesions. By minimizing its ares with optimal use, RT projects as a potent tool against such diseases. PMID: 31713498 [PubMed - as supplied by publisher]
Source: Reviews on Recent Clinical Trials - Category: Cancer & Oncology Authors: Tags: Rev Recent Clin Trials Source Type: research
This study examines outcome heterogeneity and potential to refine the TNM-8 cN-classification using radiologic extranodal extension (rENE) in a contemporary HPV-positive (HPV+) oropharyngeal carcinoma (OPC) cohort. METHODS: All HPV+ OPC treated with definitive IMRT from 2010-2015 were included. Pre-treatment CT/MR of cN+ cases were reviewed by a head-neck radiologist for rENE. Overall survival (OS) and disease-free survival (DFS) were compared between rENE-positive (rENE+) vs rENE-negative (rENE-). Multivariable analysis (MVA) for OS confirmed the prognostic value of rENE. Refined cN-classifications for new TNM stagin...
Source: Radiotherapy and Oncology : journal of the European Society for Therapeutic Radiology and Oncology - Category: Radiology Authors: Tags: Radiother Oncol Source Type: research
Publication date: February 2020Source: Safety Science, Volume 122Author(s): Natalia Silvis-Cividjian, Wilko Verbakel, Marjan AdmiraalAbstractRadiation therapy is an important technique to treat cancer. Due to the high occupational risks involved, the process is subject to severe safety regulations and standards. However, these standards do not mandate the usage of a particular hazard analysis method. The de facto methods currently used are the reliability theory-based Fault Tree Analysis (FTA) and Healthcare Failure Mode and Effects Analysis (HFMEA). Systems Theoretic Process Analysis (STPA) is a new, essentially different...
Source: Safety Science - Category: Occupational Health Source Type: research
To evaluate the results of the concurrent use of lenalidomide-dexamethasone with intensity-modulated radiation therapy (IMRT) for solitary plasmacytoma in terms of toxicity and outcomeMaterials&Methods: Forty-six patients were treated for histologically proven SP between June 2007 and June 2018 in our Department (XXX). All patients received IMRT. The median total dose was 40 Gy (range, 40-46). Prescription of concurrent lenalidomide-dexamethasone with radiotherapy was left discretion of the referring hematologist-oncologist and started the first day of radiotherapy for four cycles.
Source: International Journal of Radiation Oncology * Biology * Physics - Category: Radiology Authors: Source Type: research
Particle therapy provides steep dose gradients to facilitate dose escalation in challenging anatomical sites which has been shown not only to improve local control but also overall survival in patients with AC...
Source: Radiation Oncology - Category: Cancer & Oncology Authors: Tags: Research Source Type: research
AbstractObjectiveTo evaluate treatment outcomes after definitive chemoradiotherapy (CRT) for human papilloma virus (HPV)-negative oropharyngeal squamous cell carcinoma (OPSCC).Materials and methodsWe analyzed data concerning HPV-negative OPSCC patients treated with curative intent. All patients received concomitant high-dose cisplatin-based chemotherapy. Two different RT techniques were used: (1) sequential boost IMRT (S-IMRT) to a total dose of 70  Gy (2 Gy/fraction); (2) simultaneously integrated boost (SIB-IMRT) to a total dose of 67.5 Gy (2.25 Gy/fraction). Survival outcomes were estimated.ResultsIn...
Source: Journal of Cancer Research and Clinical Oncology - Category: Cancer & Oncology Source Type: research
We present a case of a large clival chordoma in a 54-year-old female with a past medical history of Turner's syndrome and a 1.5-year history of nasal congestion. The tumor was extending in the nasopharynx to both pterygopalatine fossae. An expanded endoscopic endonasal approach was selected. Stereotactic navigation was utilized. Bilateral transmaxillary approach with ethmoidectomy was performed, and a transclival corridor to the deepest portion of the tumor was created. The tumor was successfully dissected off the medial walls of the cavernous sinuses. Gross-macroscopic resection was achieved. Surgical reconstruction of th...
Source: Journal of Neurological Surgery Part B: Skull Base - Category: Neurosurgery Authors: Tags: Skull Base: Operative Videos Source Type: research
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