Objective: To assess the average glandular doses (AGD) from full-field digital mammography (FFDM) and digital breast tomosynthesis (DBT). Material and Methods: Radiographic exposure parameters target/filter, tube voltage, and tube current were collected from 50 patients. Patient information including age, breast thickness, entrance surface air kerma (ESAK) and AGD from the monitor display were also recorded. The tube outputs (tube voltage and tube loadings) at the reference points in both FFDM and DBT modes were measured. The AGD was calculated from ESAK by using the correction factors following the Technical Report Series no. 457 protocol. For the DBT mode, the AGD was calculated and corrected for the X-ray gantry rotation following the Dance et al. method. Results: The radiation doses to breasts in terms of ESAK and AGD from FFDM were 4.97±2.29 and 1.36±0.48 milligray (mGy) respectively. The third quartiles were 6.5 mGy and 1.67 mGy, findings which were lower than the standard Dose Reference Levels reported by the International Atomic Energy Agency recommendation (AGD 3 mGy/view for standard breast thickness with grid). For the DBT mode, ESAK and AGD were 6.49±2.10 mGy and 1.63±0.51 mGy. The third quartiles were 7.68 mGy and 1.81 mGy which were more than the FFDM mode by 23.0% and 17.0%, respectively. Conclusion: This study found that the AGD received from the DBT mode was higher than from the FFDM mode. Patients who underwent combination modes of mammographic examination increasingly received AGD up to 1.74 mGy. However, the AGD in our institute was still lower than the standard AGD recommendations.
Background: The trend in the use of fluoroscopic-guided transcatheter aortic valve implantation (TAVI) is increasing because the procedure is less invasive than surgical procedure. However, high radiation doses have been reported with the procedure. Moreover, the amount of radiation received by patients undergoing TAVI has never before been registered in Thailand. Objectives: This study aimed to investigate the radiation dose and the effects of sex and body mass index (BMI) on the radiation dose received by patients undergoing TAVI at Chulabhorn Hospital. Materials and methods: Data were collected on the radiation dose received by patients undergoing the TAVI procedure during the first 26 months after the operation at the Cardiology Center, Chulabhorn Hospital. We recorded patient demographic data including age, sex, and BMI and the following measures of radiation dose from the procedure: the number of exposure images, air kerma-area product (PKA), cumulative air kerma at the patient entrance reference point (Ka,r), and total fluoroscopy time. Results: In total, 68 patients (35 male and 33 female) underwent TAVI, with median exposure images, PKA, Ka,r, and total fluoroscopy time of 1,067 images, 166.14 Gy/cm2, 1,171.50 mGy, and 31.90 minutes, respectively. The patient’s sex did not affect total fluoroscopy time or the radiation dose received. Patients with BMI ≥30.0 kg/m2 had the highest median values of PKA, Ka,r, and total fluoroscopy time. Moreover, patients with BMI ≥18.5-24.9 kg/m2 received higher doses of radiation than patients with BMI ≥25.0-29.9 kg/m2; the result corresponded with longer total fluoroscopy time in the lower BMI category. Conclusion: The amount of radiation that patients received during TAVI was appropriate for diagnosis and treatment. However, to ensure patient safety, operators should consider reducing the duration of radiation during the procedure. Data from this study are a starting point for the recording of radiation doses received by patients undergoing TAVI and can be used as a future dose reference.
Objective: To investigate the effective radiation dose and image quality of computed tomography angiography (CTA) before transcatheter aortic valve implantation (TAVI). Material and Methods: This study involved 65 participants, diagnosed with aortic valve stenosis and examined with CTA before TAVI. The total mAs, kVp, volume CT dose index (CTDIvol), and dose–length product (DLP) in each scanning phase were recorded. The effective dose was calculated by multiplying the DLP by the conversion coefficient (k=0.015 mSv/[mGy.cm]). For quantitative image analysis, circular regions of interest were placed on six levels of the aorta in the axial images. The CT attenuation value, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured. For qualitative analysis, two radiologists rated the image quality of the aortic root and aortoiliac pathway. Results: The mean CTDIvol and DLP were 23.59±5.19 mGy and 881.01±193.41 mGy.cm., respectively. The mean effective dose was 13.22±2.90 mSv; the whole-aorta CTA phase received the highest dose, followed by the coronary CTA and coronary artery calcium scoring phases (9.62±2.60, 2.44±1.13, and 1.16±0.55 mSv, respectively). Image quality ranged from good to excellent in all segments of the aorta. Conclusion: The mean effective radiation dose of the pre-TAVI CT examination using 256-multidetector CT was 22.91± 5.03 mSv. The image quality in the aorta was good to excellent. The main factors that affected the radiation dose were: body mass index, total mAs, and kVp.
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