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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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CONCLUSION: R0 resection, the goal of neoadjuvant treatment, can be achieved in 70% of patients presenting with locally advanced pancreatic cancer. The median DFS was 31 months (95% CI: 11. 3-51.1). No relationship was found with tumor size, degree of vascular involvement, carcinoembryonic antigen test (CEA), CA 19-9, degree of tumor regression on scan, fall in CA 19-9, or SUV on PET scan and subsequent survival. PMID: 29212734 [PubMed - as supplied by publisher]
Source: The Oncologist - Category: Cancer & Oncology Authors: Tags: Oncologist Source Type: research
Rationale: Regorafenib is the new standard third-line therapy in metastatic colorectal cancer (mCRC). However, the reported 1-year overall survival rate does not exceed 25%. Patient concerns: A 55-year-old man affected by mCRC, treated with regorafenib combined with stereotactic body radiotherapy (SBRT), showing a durable response. Interventions: After 6 months of regorafenib, a PET/CT scan revealed a focal uptake in a solid lung nodule which was treated with SBRT, whereas continuing regorafenib administration. Fourteen months later, the patient had further progression in a parasternal lymph node, but treatment wit...
Source: Medicine - Category: Internal Medicine Tags: Research Article: Clinical Case Report Source Type: research
This study aimed to investigate the relationship between dose and radiation-induced liver disease (RILD) in patients with hepatocellular carcinoma (HCC) receiving 3-dimensional conformal radiotherapy (3DCRT). Twenty-three patients with HCC who received conventional fractionated 3DCRT, including 7 who were diagnosed with classic RILD, were enrolled in this retrospective investigation. Cone-beam computed tomography (CBCT) scans were acquired at the time of treatment for each patient. The beams from each patient's treatment plan were applied to each pretreatment CBCT (the modified CBCT or mCBCT) to construct the delivered dos...
Source: Medical Dosimetry - Category: Radiology Authors: Tags: Medical Physics Contribution: Source Type: research
Conclusion: Our study, the largest of its kind, confirms that, when using 18F-FDG PET/CT for staging, restaging, or surveillance of malignant cutaneous melanoma in patients without previously known or suspected lower-limb melanoma lesions, imaging the lower extremities offers little additional clinically relevant information and stopping the scan at the proximal thighs has essentially no clinical impact.
Source: Nuclear Medicine Communications - Category: Nuclear Medicine Tags: Original Articles Source Type: research
Conclusions mDIBH is efficient and can effectively decrease mean heart dose in patients with unfavorable cardiac anatomy who need IMLN-RT, thus simplifying planning and delivery for them. The reduction in mean heart dose is proportional to the reduction in maximum heart distance.
Source: Practical Radiation Oncology - Category: Cancer & Oncology Source Type: research
Conclusion Two-dimensional treatment techniques risk geographic miss of IMNs and exposure of excess normal tissue to radiation. An IMN-CTV defined by the IMVs from the first to third ICs with 0.5-cm medial and lateral margin expansion encompasses almost all i-IMNs identified on PET-CT imaging. Inclusion of the fourth IC offers modest coverage improvement, and its inclusion should be weighed against potential increase in cardiac exposure. Summary The use of 2-dimensional treatment techniques for adjuvant internal mammary lymph node (IMN) radiation may cause geographic miss of tumor and expose normal tissue to radiation inju...
Source: Practical Radiation Oncology - Category: Cancer & Oncology Source Type: research
Conclusions For pancreas SBRT, we recommend combining the GTVs from a multiphasic CT simulation with bolus-tracking, including, at a minimum, a Boolean “OR” of the LA and PV phases.
Source: Practical Radiation Oncology - Category: Cancer & Oncology Source Type: research
To determine the potential role of 68Ga-PSMA positron emission tomography/computed tomography (PET/CT) in radiotherapy (RT) planning for prostate cancer (PCa).
Source: Radiation Oncology - Category: Cancer & Oncology Authors: Tags: Research Source Type: research
Conclusions This case shows a successful robotic management of recurrent endometrial cancer.
Source: Journal of Minimally Invasive Gynecology - Category: OBGYN Source Type: research
Rationale: Thyroid metastasis from nasopharyngeal carcinoma is rare. Metastasis of nasopharyngeal carcinoma to the thyroid gland with subsequent metastatic abdominal lymph nodes hasn’t been reported before. We want to share our experience about the treatment choice. Patient concerns: A 27-year-old man was diagnosed with nasopharyngeal nonkeratinizing carcinoma in August 2004. In March 2013 he underwent a thyroid carcinoma radical operation, and histological examination revealed metastasis to the thyroid gland from nasopharyngeal carcinoma. An 18F-FDG-PET/CT scan and biopsy showed metastatic abdominal lymph nodes...
Source: Medicine - Category: Internal Medicine Tags: Research Article: Clinical Case Report Source Type: research
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