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1.
Radiography (Lond) ; 29(3): 552-556, 2023 05.
Article in English | MEDLINE | ID: mdl-36958232

ABSTRACT

OBJECTIVE: To explore the potentials of adding copper (Cu) filter on image quality and patient dose of adult patients underwent chest X-ray examination METHODS: Patients were divided into four groups. Group 1, patients were exposed with no added Cu filter (standard or control), group 2 a 0.1 mm Cu filter was added, group 3 acquired with 0.2 mm Cu filter and group 4 performed with 0.3 mm Cu filter. Exposure index (EI), entrance surface dose (ESD) and dose area product (DAP) were recorded from the modality and retrospectively analyzed. The visual grading analysis score (VGAS) was used to evaluate image quality. Mann-Whitney T-Test and one-way ordinary ANOVA Test were used to evaluate statistical differences including gender-based findings. RESULTS: EI, ESD and DAP data for a total of 784 patients (422 male and 362 female) that underwent indirect digital chest radiography exam were collected. Image quality was maintained when adding 0.1 mm Cu filter achieved with ∼19% DAP reduction. Female showed a significant DAP reduction comparing to male registered in the same group. CONCLUSIONS: Reducing dose when using indirect digital chest radiography is possible with no trade-off on image quality. No loss of image quality was reported, images were broadly comparable. IMPLICATIONS FOR PRACTICE: This study highlights the importance of utilizing the additional copper filter in digital chest radiography.


Subject(s)
Copper , Radiographic Image Enhancement , Humans , Male , Adult , Female , Radiation Dosage , X-Rays , Retrospective Studies , Radiographic Image Enhancement/methods
2.
Pract Radiat Oncol ; 7(2): 126-136, 2017.
Article in English | MEDLINE | ID: mdl-28089481

ABSTRACT

PURPOSE: Local recurrence is a common and morbid event in patients with unresectable pancreatic adenocarcinoma. A more conformal and targeted radiation dose to the macroscopic tumor in nonmetastatic pancreatic cancer is likely to reduce acute toxicity and improve local control. Optimal soft tissue contrast is required to facilitate delineation of a target and creation of a planning target volume with margin reduction and motion management. Magnetic resonance imaging (MRI) offers considerable advantages in optimizing soft tissue delineation and is an ideal modality for imaging and delineating a gross tumor volume (GTV) within the pancreas, particularly as it relates to conformal radiation planning. Currently, no guidelines have been defined for the delineation of pancreatic tumors for radiation therapy treatment planning. Moreover, abdominal MRI sequences are complex and the anatomy relevant to the radiation oncologist can be challenging. The purpose of this study is to provide recommendations for delineation of GTV and organs at risk (OARs) using MRI and incorporating multiple MRI sequences. METHODS AND MATERIALS: Five patients with pancreatic cancer and 1 healthy subject were imaged with MRI scans either on 1.5T or on 3T magnets in 2 separate institutes. The GTV and OARs were contoured for all patients in a consensus meeting. RESULTS: An overview of MRI-based anatomy of the GTV and OARs is provided. Practical contouring instructions for the GTV and the OARs with the aid of MRI were developed and included in these recommendations. In addition, practical suggestions for implementation of MRI in pancreatic radiation treatment planning are provided. CONCLUSIONS: With this report, we attempt to provide recommendations for MRI-based contouring of pancreatic tumors and OARs. This could lead to better uniformity in defining the GTV and OARs for clinical trials and in radiation therapy treatment planning, with the ultimate goal of improving local control while minimizing morbidity.


Subject(s)
Adenocarcinoma/diagnostic imaging , Adenocarcinoma/radiotherapy , Magnetic Resonance Imaging/methods , Pancreatic Neoplasms/diagnostic imaging , Pancreatic Neoplasms/radiotherapy , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Conformal , Adenocarcinoma/pathology , Adult , Aged , Aged, 80 and over , Humans , Male , Neoplasm Recurrence, Local/diagnostic imaging , Neoplasm Staging , Organs at Risk/diagnostic imaging , Pancreatic Neoplasms/pathology , Practice Guidelines as Topic , Radiation Dosage , Tomography, X-Ray Computed , Tumor Burden , Young Adult
3.
Phys Med Biol ; 55(3): 681-94, 2010 Feb 07.
Article in English | MEDLINE | ID: mdl-20071761

ABSTRACT

There is much interest in positron emission tomography (PET) for measurements of regional tracer concentration in hypoxic tumour-bearing tissue, focusing on the need for accurate radiotherapy treatment planning. Generally, relevant data are taken over multiple time frames in the form of tissue activity curves (TACs), thus providing an indication of vasculature structure and geometry. This is a potential key in providing information on cellular perfusion and limited diffusion. A number of theoretical studies have attempted to describe tracer uptake in tissue cells in an effort to understand such complicated behaviour of cellular uptake and the mechanism of washout. More recently, a novel computerized reaction diffusion equation method was developed by Kelly and Brady (2006 A model to simulate tumour oxygenation and dynamic [18F]-FMISO PET data Phys. Med. Biol. 51 5859-73), where they managed to simulate the realistic dynamic TACs of (18)F-FMISO. The model was developed over a multi-step process. Here we present a refinement to the work of Kelly and Brady, such that the model allows simulation of a realistic tissue activity curve (TAC) of any hypoxia selective PET tracer, in a single step process. In this work we show particular interest in simulating the TAC of perhaps the most promising hypoxia selective tracer, (64)Cu-ATSM. In addition, we demonstrate its potential role in tumour sub-volume delineation for radiotherapy treatment planning. Simulation results have demonstrated the significant high contrast of imaging using ATSM, with a tumour to blood ratio ranging from 2.24 to 4.1.


Subject(s)
Computer Simulation , Contrast Media/pharmacokinetics , Copper Radioisotopes/pharmacokinetics , Organometallic Compounds/pharmacokinetics , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy/methods , Thiosemicarbazones/pharmacokinetics , Algorithms , Blood Vessels/metabolism , Cell Hypoxia , Coordination Complexes , Diffusion , Humans , Misonidazole/analogs & derivatives , Misonidazole/pharmacokinetics , Models, Biological , Neoplasms/blood supply , Neoplasms/metabolism , Neoplasms/radiotherapy , Oxygen/metabolism , Positron-Emission Tomography/methods
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