A Monte Carlo study of organ and effective doses of cone beam computed tomography (CBCT) scans in radiotherapy

Cone-beam CT (CBCT) scans utilised for image guided radiation therapy (IGRT) procedures have become an essential part of radiotherapy. The aim of this study was to assess organ and effective doses resulting from new CBCT scan protocols (head, thorax, and pelvis) released with a software upgrade of the kV on-board-imager (OBI) system. Organ and effective doses for protocols of the new software (V2.5) and a previous version (V1.6) were assessed using Monte Carlo (MC) simulations for the International Commission on Radiological Protection (ICRP) adult male and female reference computational phantoms. The number of projections and the mAs values were increased and the size of the scan field was extended in the new protocols. Influence of these changes on organ and effective doses of the scans was investigated. The OBI system was modelled in EGSnrc/BEAMnrc, and organ doses were estimated using EGSnrc/DOSXYZnrc. The MC model was benchmarked against experimental measurements. Organ dos...
Source: Journal of Radiological Protection - Category: Physics Authors: Source Type: research

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This study aimed to increase the knowledge on the relation between CBCT organ doses and weighted CTDI (CTDIW) for a thorax scanning protocol. A CBCT system was modelled using the Monte Carlo (MC) radiation transport program MCNPX2.7.0. Simulation results were validated against half-value layer (HVL), axial beam profile, patient skin dose (PSD) and CTDI measurements. For organ dose calculations, a male voxel phantom ("Golem") was implemented with the CBCT scanner computational model. After a successful MC model validation with measurements, a systematic comparison was performed between organ doses (and their distr...
Source: Radiation and Environmental Biophysics - Category: Physics Authors: Tags: Radiat Environ Biophys Source Type: research
Conclusions Laparoscopic anterior pelvic exenteration with radical colpectomy using 3D vision and multifunction instrument is a fast and safe procedure. However, we notice that further prospective trials are needed to compare this technique with other open surgery and minimally invasive approach (ie, robotically).
Source: International Journal of Gynecological Cancer - Category: Cancer & Oncology Tags: Surgeons Corner Source Type: research
Vereos PET/CT, Software version 2.0.1. Model Number: 882446 Product Usage: The Philips Vereos PET/CT system is a diagnostic imaging device that combines Positron Emission Tomography (PET) and X-ray Computed Tomography (CT) systems. The CT subsystem images anatomical cross-sections by computer reconstruction of X-ray transmission data. The PET subsystem images the distribution of PET anatomy-specific radiopharmaceuticals in the patient. The PET/CT system is used for the purposes of detecting, localizing, diagnosing, staging, re-staging, and follow-up for monitoring therapy response of various diseases in oncology, cardiolo...
Source: Medical Device Recalls - Category: Medical Devices Source Type: alerts
CONCLUSION: No significant difference in the rates of fiducial marker retention and migration were noted when comparing patients who had anchored transponders placed into small airways and a 2:1 matched cohort of patients who had other commercially available lung fiducial markers placed. In both groups, no late or chronic toxicity appeared to be related to the implanted fiducial markers. PMID: 30387242 [PubMed - as supplied by publisher]
Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research
Abstract Accurate tumor delineation is a priority in radiation therapy (RT). Metabolic imaging has a key and evolving role in target volume selection and delineation. This is especially so for non-small cell lung cancer, squamous cell cancer of the head and neck, and lymphoma, for which positron emission tomography/computed tomography (PET/CT) is complimentary to structural imaging modalities, not only in delineating primary tumors, but also often in revealing previously undiagnosed regional nodal disease. At some sites, PET/CT has been confirmed to enable target size reduction compared with structural imaging alo...
Source: Health Physics - Category: Physics Authors: Tags: Int J Radiat Oncol Biol Phys Source Type: research
At the American Society for Radiation Oncology annual meeting, Siemens Healthineers has unveiled its RT Pro edition for Biograph Vision PET/CT scanner and MAGNETOM Sola 1.5 Tesla MRI machine to help with radiation therapy planning. Bot...
Source: Medgadget - Category: Medical Devices Authors: Tags: Oncology Radiation Oncology Radiology Source Type: blogs
ConclusionsGenerally, superior vena cava syndrome is the result of extrinsic compression of the superior vena cava by tumor. Our patient ’s case represents the development of superior vena cava syndrome after an excellent response of tumor with near-complete tumor response. We suspect chemoradiation therapy as a potential etiology for the precipitation of the superior vena cava syndrome, which is currently not well reported in the medical literature.
Source: Journal of Medical Case Reports - Category: General Medicine Source Type: research
Researchers from China have developed a radiomics model that can determine...Read more on AuntMinnie.comRelated Reading: Radiomics helps distinguish lung cancer nodules on CT AIUM: Can deep learning classify liver fibrosis on US? AI, radiomics help distinguish lung nodules on CT scans MRI, radiomics help diagnose, discern ADHD subtypes AAPM: Radiomics helps fine-tune radiation therapy dose
Source: AuntMinnie.com Headlines - Category: Radiology Source Type: news
Abstract PURPOSE: Stereotactic body radiation therapy is a promising treatment modality for locally advanced pancreatic cancer. To determine the optimal radiation treatment, we compared the plan characteristics of volumetric-modulated arc therapy and intensity-modulated radiation therapy when administered with stereotactic body radiation therapy to treat pancreatic cancer. PATIENTS AND METHODS: Fifteen patients with locally advanced pancreatic cancer were treated by stereotactic body radiation therapy at a dose of 24-32Gy in four fractions with marker-guided gated volumetric-modulated arc therapy. Four dimens...
Source: Cancer Radiotherapie - Category: Cancer & Oncology Authors: Tags: Cancer Radiother Source Type: research
This study aimed to develop action levels for replanning to accommodate dosimetric variations resulting from anatomic changes during the course of treatments, using daily cone beam computed tomography (CBCT).Methods and materialsDaily or weekly CBCT images of 20 patients (10 head and neck, 5 lung, and 5 prostate cancers) who underwent resimulation per physicians' clinical decisions, mainly from the comparison of CBCT scans, were used to determine action levels. The first CBCT image acquired before the first treatment was used as the reference image to rule out effects of dose inaccuracy from the CBCT. The Pearson correlati...
Source: Practical Radiation Oncology - Category: Cancer & Oncology Source Type: research
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