Estimating Local Diagnostic Reference Levels for Mammography in Dubai.

As the total volume of mammograms in Dubai is increasing consistently, it is crucial to focus on the process of dose optimization by determining dose reference levels for such sensitive radiographic examinations as mammography. This work aimed to determine local diagnostic reference levels (DRLs) for mammography procedures in Dubai at different ranges of breast thickness. A total of 2599 anonymized mammograms were randomly retrieved from a central dose survey database. Mammographic cases for screening women aged from 40 to 69 years were included, while cases of breast implants and breast thickness outside the range of 20-100 mm were excluded. Mean, median, and 75 percentiles were obtained for the mean glandular dose (MGD) distribution of each mammography projection for all compressed breast thickness (CBT) ranges. The local DRLs for mammography in Dubai were found to be between 0.80 mGy and 0.82 mGy for the craniocaudal (CC) projection and between 0.89 mGy and 0.971.8 mGy for the mediolateral oblique (MLO) projection. Local DRLs were proposed according to different breast thicknesses, starting from 20 to 100 mm. All groups of CBT showed a slight difference in MGD values, with higher values in MLO views rather than CC views. The local DRLs in this study were lower than some other Middle Eastern countries and lower than the standard reference levels reported by the International Atomic Energy Agency (IAEA) at 3 mGy/view.

Effectiveness of an educational module in improving knowledge, awareness and perception among pregnant women regarding the safe use of prenatal ultrasound.

Background: Lack of public understanding, perception and awareness of the biological effects of prenatal ultrasound has led to the non-medical use of ultrasound. An educational programme is required to enlighten pregnant women and the public regarding prenatal ultrasound safety. Objective: To evaluate the effectiveness of educational modules (video and brochure) in improving knowledge, awareness and perception (KAP) among pregnant women regarding prenatal ultrasound safety. Methods: This is a quasi-experimental study with a pre-and post-test design. This study recruited 51 pregnant women as respondents from the Obstetrics and Gynaecology clinic (O&G) of Hospital Canselor Tuanku Muhriz (HCTM). The first phase of the study was conducted by distributing a set of closed-ended questionnaires with multiple choice and Likert scale answers to assess the KAP of pregnant women regarding the safe use of prenatal ultrasound, followed by educational modules where the respondents were allocated into three groups (17 watched a video, 17 received brochure and 17 received combined media). After the intervention, the respondents' KAP were assessed using the same questionnaire. Results: The Wilcoxon signed rank test showed that educational modules like video, brochure and combined media had a statistically significant increase in post-test scores over the pre-test scores (video: mean rank = 9.00, p < 0.05) (brochure: mean rank = 9.79,p < 0.05) and (combined media: mean rank = 10.17, p > 0.05). The Kruskal Wallis test indicated that educational video was more effective in improving the KAP of pregnant women than the brochure and combined media (mean rank = 34.62, p < 0.05). Among the parameters, the occupation has the strongest positive correlation with the post-test knowledge score in improving the KAP of pregnant women regarding the safe use of prenatal ultrasound. Conclusion: The educational video is the most effective approach for enhancing pregnant women's KAP. The educational module on the safety of prenatal ultrasound is thought to dispel myths by providing accurate information to audiences from various backgrounds.

Stability and Reproducibility of Radiomic Features Based Various Segmentation Technique on MR Images of Hepatocellular Carcinoma (HCC).

Hepatocellular carcinoma (HCC) is considered as a complex liver disease and ranked as the eighth-highest mortality rate with a prevalence of 2.4% in Malaysia. Magnetic resonance imaging (MRI) has been acknowledged for its advantages, a gold technique for diagnosing HCC, and yet the false-negative diagnosis from the examinations is inevitable. In this study, 30 MR images from patients diagnosed with HCC is used to evaluate the robustness of semi-automatic segmentation using the flood fill algorithm for quantitative features extraction. The relevant features were extracted from the segmented MR images of HCC. Four types of features extraction were used for this study, which are tumour intensity, shape feature, textural feature and wavelet feature. A total of 662 radiomic features were extracted from manual and semi-automatic segmentation and compared using intra-class relation coefficient (ICC). Radiomic features extracted using semi-automatic segmentation utilized flood filling algorithm from 3D-slicer had significantly higher reproducibility (average ICC = 0.952 ± 0.009, p < 0.05) compared with features extracted from manual segmentation (average ICC = 0.897 ± 0.011, p > 0.05). Moreover, features extracted from semi-automatic segmentation were more robust compared to manual segmentation. This study shows that semi-automatic segmentation from 3D-Slicer is a better alternative to the manual segmentation, as they can produce more robust and reproducible radiomic features.

Establishment of CTPA Local Diagnostic Reference Levels with Noise Magnitude as a Quality Indicator in a Tertiary Care Hospital.

This study aimed to establish the local diagnostic reference levels (LDRLs) of computed tomography pulmonary angiography (CTPA) examinations based on body size with regard to noise magnitude as a quality indicator. The records of 127 patients (55 males and 72 females) who had undergone CTPAs using a 128-slice CT scanner were retrieved. The dose information, scanning acquisition parameters, and patient demographics were recorded in standardized forms. The body size of patients was categorized into three groups based on their anteroposterior body length: P1 (14-19 cm), P2 (19-24 cm), and P3 (24-31 cm), and the radiation dose exposure was statistically compared. The image noise was determined quantitatively by measuring the standard deviation of the region of interest (ROI) at five different arteries-the ascending and descending aorta, pulmonary trunk, and the left and right main pulmonary arteries. We observed that the LDRL values were significantly different between body sizes (p < 0.05), and the median values of the CT dose index volume (CTDIvol) for P1, P2, and P3 were 6.13, 8.3, and 21.40 mGy, respectively. It was noted that the noise reference values were 23.78, 24.26, and 23.97 HU for P1, P2, and P3, respectively, which were not significantly different from each other (p > 0.05). The CTDIvol of 9 mGy and dose length product (DLP) of 329 mGy∙cm in this study were lower than those reported by other studies conducted elsewhere. This study successfully established the LDRLs of a local healthcare institution with the inclusion of the noise magnitude, which is comparable with other established references.

Effect of miscentering and low-dose protocols on contrast resolution in computed tomography head examination.

BACKGROUND: Unoptimized protocols, including a miscentered position, might affect the outcome of diagnostic in CT examinations. In this study, we investigate the effects of miscentering position during CT head examination on the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). METHOD: We simulate the CT head examination using a water phantom with a standard protocol (120 kVp/180 mAs) and a low dose protocol (100 kVp/142 mAs). The table height was adjusted to simulate miscentering by 5 cm from the isocenter, where the height was miscentered superiorly (MCS) at 109, 114, 119, and 124 cm, and miscentered inferiorly (MCI) at 99, 94, 89, and 84 cm. Seven circular regions of interest were used, with one drawn at the center, four at the peripheral area of the phantom, and two at the background area of the image. RESULTS: For the standard protocol, the mean CNR decreased uniformly as table height increased and significantly differed (p < 0.05) at +20 cm for MCS (435.70 ± 9.39) and -20 cm for MCI (438.91 ± 10.94) from the isocenter. Similarly, significant reductions (p < 0.05) were also noted for SNR for MCS (at +20 cm) and MCI (at -20 cm). For the low dose protocol, both CNR and SNR were significantly reduced (p < 0.05) at table heights of +20 and -20 cm from the isocenter. CONCLUSION: Miscentering is proven to significantly affect the image quality in both low and standard dose protocols for head CT procedure. This study implies that accurate patient centering is one of the approaches that can improve CT optimization practice.

Ultrasound exposure during pregnancy affects rabbit foetal parathyroid hormone (PTH) level.

The aim of this study was to investigate the changes in parathyroid hormone (PTH) level of rabbit foetal bodies exposed to ultrasound at different gestational stages. A total of 9 pregnant rabbits (Oryctolagus cuniculus) were insonated for 60 minutes at the middle of 1(st), 2(nd) and 3(rd) gestational stages for group A (n=14 newborns), group B (n=7 newborns) and group C (n=24 newborns) respectively. Seven pregnant rabbits with 41 newborns severed as negative control group. Blood samples were withdrawn from each newborn rabbits for Parathyroid Hormone-Intact (PTH-I) test. Results of the independent samples t-test implied statistically significant differences (P<0.05) between the control group and the 1(st) stage (P=0.001), the 2(nd) stage (P<0.001) and the 3(rd) stage group (P<0.001). This in-vivo study revealed diagnostic ultrasound heating has the potential of affecting foetal PTH level. This study observed significantly low PTH level for all the treated groups. A further study should be instituted to determine whether this finding in rabbit may also occur in human by means of clinical trials.