PSF reconstruction for Compton-based prompt gamma imaging.

In this study, we investigate the performance of the list-mode ordered subset expectation maximization algorithm with a shift-variant point spread function model (LM-OSEM-SV-PSF). We also evaluate how well the PG images reconstructed using a SV-PSF model reproduce the distal falloff of the proton beam. SV-PSF parameters were estimated by simulation data of point sources at various positions. Simulated PGs were produced in a water phantom irradiated with a proton beam. Compared to the LM-OSEM algorithm, the LM-OSEM-SV-PSF algorithm improved the quality of the reconstructed PG images and the estimation of PG falloff positions. In addition, the 4.44 and 5.25 MeV PG emissions can be accurately reconstructed using the LM-OSEM-SV-PSF algorithm. However, for the 2.31 and 6.13 MeV PG emissions, the LM-OSEM-SV-PSF reconstruction provides limited improvement. We also found that the LM-OSEM algorithm followed by a shift-variant Richardson-Lucy deconvolution could reconstruct images with quality visually similar to the LM-OSEM-SV-PSF reconstructed images while requiring shorter computation time. PMID: 29189207 [PubMed - as supplied by publisher]
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research

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Despite widespread concerns of radiotherapy toxicity in children with head and neck tumors, recent Children ’s Oncology Group (COG) findings suggest that the use of 45 Gy results in an unacceptably high rate of local recurrences in patients with Group III orbital rhabdomyosarcoma. We therefore evaluated outcomes in our pediatric patients who received 45 GyRBE using proton therapy to a post-induction che motherapy target volume.
Source: International Journal of Radiation Oncology * Biology * Physics - Category: Radiology Authors: Source Type: research
In this study the role of pencil beam proton therapy (PBS) in reducing the doses to the cochlea in children receiving CSI and correlation to the early ototoxicity are analysed.
Source: International Journal of Radiation Oncology * Biology * Physics - Category: Radiology Authors: Source Type: research
Pediatric optic pathway glioma (POPG) is frequently treated with radiotherapy (RT). We evaluated the radiographic response and clinical outcomes after proton therapy (PBT).
Source: International Journal of Radiation Oncology * Biology * Physics - Category: Radiology Authors: Source Type: research
There are no established imaging biomarkers that predict response during chemoradiation for patients with locally-advanced NSCLC (LA-NSCLC). At our institution, proton therapy (PT) patients undergo repeat CT-simulations twice during radiation. We hypothesized that tumor regression measured on these scans would separate early and late responders, and that early response would translate into better outcomes.
Source: International Journal of Radiation Oncology * Biology * Physics - Category: Radiology Authors: Source Type: research
Research on side effects of radiotherapy has been a steadily growing field of interest, as advances in treatment (e.g. multimodality imaging, proton therapy, targeted agents) have led to both increased life expectancy in cancer survivors and a greater degree of control in sparing organs-at-risk (OARs) [1]. Adequate delineation of OARs is crucial when investigating the association between radiation dose and side effects and when optimizing treatment planning. However, manual contouring of OARs is very time-consuming [2] and is prone to inter-observer variability [3,4].
Source: Radiotherapy and Oncology - Category: Radiology Authors: Tags: Original Article Source Type: research
ConclusionDespite the dosimetric precision of proton therapy, orbital asymmetry will develop after>40 GyRBE to multiple bones of the orbital rim. These data may be used to guide treatment planning and counsel patients on expected cosmesis.
Source: Practical Radiation Oncology - Category: Cancer & Oncology Source Type: research
CONCLUSION: There were large differences in morbidity predictions between cohorts and modalities, indicating that the validity of NTCP models and parameters across institutions and treatment modalities should be carefully investigated prior to clinical application. PMID: 31630864 [PubMed - as supplied by publisher]
Source: Radiotherapy and Oncology : journal of the European Society for Therapeutic Radiology and Oncology - Category: Radiology Authors: Tags: Radiother Oncol Source Type: research
Penn Medicine Lancaster General Health has started construction of a $48 million proton therapy center. The proton therapy center, part of Lancaster General Health's Ann B. Barshinger Cancer Institute, will be the second site in Pennsylvania to offer the high-tech form of radiation therapy to cancer patients when it opens in the fall of 2021. The first proton therapy center in Pennsylvania opened a t Penn, in a 75,000-square-foot building that is part of the Abramson Cancer Center, in 2010. Penn…
Source: Health Care:Pharmaceuticals headlines - Category: Pharmaceuticals Authors: Source Type: news
PALO ALTO, Calif., Oct. 14, 2019 /PRNewswire/ -- Varian (NYSE: VAR) in collaboration with Cincinnati Children's Hospital Medical Center/University of Cincinnati Medical Center Proton Therapy Center announced the achievement of a significant milestone in the path towards clinical trials of FLASH therapy*. The combined research team utilized a Varian ProBeam® proton therapy gantry treatment room in research mode to successfully complete a FLASH delivery to a phantom target. This...This story is related to the following:Radiotherapy Systems |
Source: Industrial Newsroom - Health, Medical and Dental Supplies - Category: Medical Devices Source Type: news
Study Objectives:Children with craniopharyngioma are at risk for excessive daytime sleepiness (EDS). Multiple Sleep Latency Testing (MSLT) is the gold standard for objective evaluation of EDS; however, it is time and resource intensive. We compared the reliability, sensitivity, and specificity of the modified Epworth Sleepiness Scale (M-ESS) and MSLT in monitoring EDS in children with craniopharyngioma.Methods:Seventy patients (ages 6 to 20 years) with craniopharyngioma completed the M-ESS and were evaluated by polysomnography and MSLT. Evaluations were made after surgery, if performed, and before proton therapy.Results:MS...
Source: Journal of Clinical Sleep Medicine : JCSM - Category: Sleep Medicine Source Type: research
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