Browsing by Author "Vicente, Ana Cristina"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Arms up vs. arms down: CT dose optimizationPublication . Borlinhas, Filipa; Vicente, Ana Cristina; Venâncio, JoséIntroduction - Computed Tomography (CT) technologies are evolving in terms radiation dose optimization. When a transition of CT technology takes place, every procedure should be revised and questioned in terms of radiation dose optimization. A procedure such as positioning a patient for a CT examination may be considered simple, but it may become radical concerning radiation dose. The CT examination of Neck+Thorax+Abdomen+Pelvis (NTAP) requires a large anatomical region to be irradiated and, in most of the cases, the patients have to be scanned regularly to evaluate oncologic disease. Radiographers gathered efforts in order to optimize the delivered radiation dose of this type of examinations, and positioning of the patient during the scout was found as a dose reduction parameter. The aim of this work is to emphasize the need to constantly revise CT examination protocols and clinical practice. Methods - Two different positioning to perform the NTAP CT examination scout were tested, one with a patient with arms up and the other with arms down. In the past, these examinations were performed with arms down so it was only necessary to do the new CT examination scouts with arms up. Dose estimations provided by the CT equipment were reported and compared between the two different positioning during the scout. Results - The radiation dose for the entire NTAP examination was lower when the scout was performed with arms up. Considering AEC technology, contrast media phases, anatomical regions specificities, and patient comfort, these tests were performed without compromising the diagnosis of the patient, but significant changes had to be applied to the protocol. Conclusions - The CT technology evolution implies changes in clinical practice and examination procedures. It is extremely important that the Radiology professionals revise their practices periodically in order to find procedures that can be optimized in terms of radiation dose.
- CR radiation dose optimization strategies: clinical practice approachPublication . Borlinhas, Filipa; Afonso, José; Vicente, Ana Cristina; Venâncio, JoséIn medical radiation exposures, namely in Computed Tomography (CT), there is an inverse relationship between the image noise and radiation dose. Radiographers need to recognize the situations that require optimization and to apply optimization strategies, without compromise patient diagnosis. The purpose of this work, based on a literature review and on the analysis of routine CT procedures, is to provide an overview of CT optimization techniques feasible to implement in routine practice. The key parameters and the main situations that affect image quality and patient dose will be discussed. Several CT parameters can be adjusted such as potential and tube current, rotation time, Automatic Exposure Control (AEC), detectors configuration, slice thickness, Pitch, table speed, post-processing with the filter kernels, and so on. These parameters vary with patient anatomical region of interest, examination length, positioning, clinical information, and acquisition phases. Furthermore, there are new reconstruction algorithms developed by manufacturers that also help to optimize dose by reducing artifacts and image noise, and many studies state their superior results. Also, the knowledge on the CT parameters trade-offs between radiation dose and image quality is essential for dose optimization, so this will also be highlighted and described in this work. The solution for the excess of radiation dose problem is not only to reduce radiation dose in general but also to adequate and personalize this optimization to each patient and clinical situation. The literature points out some solutions to handle this problem and is very important that the Radiographers are familiar with those when performing CT examinations in practice.