DLP Values Research Articles

Survey on the distribution of medical imaging frequencies and dose levels for CT examinations in a comprehensive hospital in Shanghai.

With the continuous advancement and clinical application of CT technology, the increasing collective dose burden from CT scans and associated potential health risks have become significant concerns in radiation protection. Current research increasingly focuses on the cumulative effective dose (CED) resulting from multiple CT scans, often revealing patients with high CEDs, even exceeding 100 mSv. However, reports on CEDs from multiple CT scans in China are scarce. Therefore, we investigated the distribution of CT scan frequencies and CEDs at a comprehensive hospital in Shanghai, examining data from October 1, 2022, to April 30, 2024, sourced from the hospital's radiology information system. The effective dose (E) was estimated using conversion factors k and DLP values from Radiation Dose Structured Reports (RDSR). We assessed the number of CT examinations conducted per patient and evaluated the CED over 1.6 years. During this period, 112,339 CT examinations were performed. Significant differences in CT examination frequencies were observed across different age groups and examination regions (P < 0.01). A total of 78.43% of patients underwent only one CT examination in 1.6 years, while 0.03% had more than 10 examinations, with a maximum of 15. Of the patients, 67.78% (76,142 individuals) received a CED less than 10 mSv, 0.05% (53 patients) received a CED over 50 mSv, and one patient exceeded 100 mSv. In conclusion, this study underscored the necessity of monitoring patients with high CT examination frequencies and CEDs, highlighting the importance of justification and optimization in medical radiation protection.

Development of Acceptable Quality Dose (AQD) and image quality-related diagnostic reference levels for common computed tomography investigations in a tertiary care public sector hospital of Khyber Pakhtunkhwa, Pakistan.

To describe the first experience of patient dose optimization in developing AQD, SSDE and image quality-related DRLs for common CT examinations in the adult age group using the concept of AQD. The recent published IQSC from 0 to 4 were used by radiologists for the assessment of image quality. The entire data were collected for five types (brain CT, chest CT, chest HRCT, abdomen KUB CT and abdomen + pelvic CT) CT investigations based on anatomic region (head, chest and abdomen + pelvic). The entire datasets of 264 patients were categorized into three groups based on their weights: group-1 (41-60kg), group-2 (61-80kg) and group-3 (81-100kg). Only score-3 images were considered to assess median and 75th percentile values of CTDIvol and DLP to obtain AQDs and DRLs, respectively. Following the practical training of four radiologists on image quality scoring criteria for CT images, 264 (92%) out of 288 patient images were clinically acceptable as per IQSC for the study. The AQD (median) values in terms of CTDIvol for the mentioned weight groups were 25.8, 2.7, and 30.6mGy, while the median DLP values for these groups were 496, 510 and 557 mGycm, respectively, for brain CT. The 75th percentile values in terms of CTDIvol were 30.2, 35.3 and 36.2mGy, while in terms of DLP, they were 583, 619 and 781 mGycm for brain CT, respectively. Similar results are presented for the above-mentioned procedures, as well as in terms of SSDE. The first ever experience in obtaining AQD, SSDE and DRLs values for specific CT procedures couples image quality with dose indices, showing comparable values with other relevant studies. Hence, it will provide a baseline for comparison within the facility for future studies and facilitate dose optimization for other facilities aiming for improvement.

Investigating the Effects of Tube Current and Tube Voltage on Patient Dose in Computed Tomography Examinations with Principial Component Analysis and Cluster Analysis: Phantom Study.

The aim of this study was to investigate the effects of tube current and tube voltage choices on patient dose in adult and pediatric CT protocols by qualitative analysis using Principal Component Analysis (PCA), cluster analysis, and statistical analysis.Dose length product (DLP), Effective mAs (Eff. mAs), and volume-weighted CT dose index (CTDIvol) dose descriptors were obtained from 16 adult and pediatric head phantom CT examinations. Different tube voltage and tube current values were selected in both pediatric head and adult head CT imaging protocols, and PCA and cluster analysis were applied to the data obtained for qualitative analysis of the relationship between CTDIvol, Eff. mAs and Total DLP values. The two principial components (PC) with the highest values among those obtained as a result of the PCA method were used. PC1 was 70.97%, and PC2 was 28.03%. In the cluster analysis, it was observed that the values obtained from pediatric and adult phantom CT scans were classified into two different clusters. The correlation coefficient for adult patients was r = 0.998, and for pediatric patients, the correlation coefficient was r = 0.947. When the obtained clusters were examined, the degree of closeness or distance of the variables could be observed. In the study, as a result of the analysis of CTDIvol, Eff. mAs and Total DLP data based on manufacturer data at different kV and mA values with PCA and cluster analysis, it was shown that pediatric patients could be exposed to more radiation than the adult patients.

The impact of automatic tube current modulation related settings of a modern GE CT scanner on image quality and patient dose; details do matter.

To investigate the operation principles of the automatic tube current modulation (ATCM) of a modern GE healthcare CT scanner, and the impact of related settings on image quality and patient dose. A dedicated phantom (Mercury 4.0) was scanned using two of the most frequently used clinical scanning protocols (chest and abdomen-pelvis). The preset protocol settings were used as starting points (reference conditions). Scan direction, scan mode (helical vs. axial), total beam width, tube potential (kVp), and ATCM settings were then modified individually to understand their impact on radiation dose and image quality. Regarding the ATCM settings, the SmartmA minimum and maximum mA limits, and the noise index (NI) values were varied. As surrogates of patient dose, the CTDIvol and DLP values of each scan were used. As surrogates of image quality were used the image noise and the detectability index (d') of five different materials (air, solid water, polystyrene, iodine, and bone) embedded in the Mercury phantom calculated with the ImQuest software. The scanning direction did not have any effect on ATCM curves, unlike what has been observed in CT scanners from other manufacturers. Total beam width does matter, however, the SmartmA limit settings and kVp selection had the greatest impact on image quality and dose. It was seen that improper minimum mA limit settings practically invalidated the ATCM operation. In contrast, when full modulation was allowed without restrictions, noise standard deviation, and detectability index became much more consistent across the wide range of phantom diameters. For lower kVp settings an impressive dose reduction was observed that requires further investigation. SmartmA is a tool that if not properly used may increase the patient doses considerably. Therefore, its settings should be carefully adjusted for each preset different clinical protocol.

Improving the Quality of CT Images of Stroke Patients Using the SSDE and K-Means Segmentation in the Radiology Installation of RSUD A.W. Sjahranie Samarinda

Stroke examination using a CT scan is a technique that produces 3D brain images without having to do surgery. The purpose of this study was to determine the dose received by each patient who underwent a CT-scan procedure and to improve the image quality of the results. Optimization of the dose for each patient is based on a comparison between the calculated SSDE value and the DRL in the form of CTDIvol and DLP, which are implemented in Indonesia. Improving the quality of CT-Scan images through digital processing using the segmentation method to determine the stroke area. The method used is K-Means segmentation. The results obtained for the SSDE value are the dose received by the patient which is higher than the dose issued by the device or the value. However, the SSDE, CTDIvol, and DLP values are still below the DRL standard range set by BAPETEN, so they are still within the safe inspection threshold. The average CTDIvol value, which is the output dose value of the device from 22 patients, was 41.84 mGy and the 75th percentile value was 42.7 mGy. The average DLP value is 1054.08 mGy.cm and the 75th percentile value of the DLP value is 964.13 mGy.cm. The average value of the SSDE value which is the value of the dose received by the patient is 43.39 mGy and the 75th percentile value is 42.440 mGy. Based on these results, the value of the dose received by the patient is higher than the value of the dose issued by the device. Segmentation using the K-Means method with the number of clusters k = 3 produces an accuracy of 86.3%. This means that the patient receives a dose of CT-Scan radiation within safe limits and his image can be processed properly, as evidenced by the high success of the segmentation process.

Evaluation of Skin and Organ Dose of Patients Caused by Computed CT and Comparison with Monte Carlo Simulation Software GEANT4 (GATE)

Today, the use of CT scan as a type of diagnostic tool has increased dramatically. Therefore, controlled use and in accordance with protective regulations in order to reduce the harmful effects of radiation, it is necessary. The purpose of this study was to measure the dose received by patients in computed CT scan protocols and compare it with Monte Carlo simulation using GEANT4 software. Radiation parameters were collected from 11 patients referred to Tohid Hospital in Sanandaj to measure DLP quantity in common protocols. In this study, DLP values for Chest Abdomen protocol were measured and compared with simulation values. Our results show Monte Carlo software outputs experimental data well and is a good benchmark for this software. Thus, the simulated and measured doses agreed well.

Evaluasi Nilai Diagnostic Reference Level (DRL) pada pemeriksaan CT Scan Thorax Kontras klinis tumor paru di RS X Jakarta

A contrast thorax CT scan is a CT scan procedure in the chest area (thorax) that uses a contrast agent to improve visualization of organs and structures in the chest. Lung tumors are the growth of abnormal lumps in lung tissue which can be benign or malignant. Awareness of the potential and increasing radiation dose in all CT scan examinations encourages radiographers to want and be able to minimize radiation exposure as the main goal in radiological examinations and also strive for radiation protection during examinations. CT scan radiation dose accounts for 70% of the total dose received from medical imaging. High or low doses of radiation received can increase the risk of cancer. The large dose of radiation received by a patient during a CT scan, therefore regulations are needed that will guarantee monitoring of the radiation dose received by the patient to ensure that the dose received is commensurate with medical purposes. The radiation dose to the patient needs to be optimized by applying the Diagnostic Reference Level (DRL) to optimize medical exposure protection for the patient. Dosage evaluation in clinical contrast chest CT scan examinations for lung tumors and the application of DRL in these examinations have never been carried out at RS X Jakarta. Objective: This study aims to determine the DRL value in clinical contrast thorax CT scan examination of lung tumors at RS CTDIvol and DLP values from clinical contrast Thorax CT Scan examination of lung tumors. The DRL value is calculated at Quartile 3 (75 percentile) using the descriptive frequency test and Wilcoxon test in the SPSS application, then compared with the latest IDRL value. Results: Quartile 3 value (75 percentile) from CTDIvol and DLP CT scan chest contrast clinical lung tumors, namely The CTDIvol value was 12.55 mGy and the DLP was 439 mGy.cm. Conclusion: The DRL value in the clinical contrast thorax CT scan for lung tumors at Hospital X Jakarta. is still below the recommended standard, which shows that the radiation output dose in this examination practice is within normal limits and is classified as safe.

Assessment of radiation exposure among pediatric patients referred for CT imaging at three government hospitals in Addis Ababa, Ethiopia.

Due to the high sensitivity of their growing tissues to ionizing radiation, pediatric patients are at a greater risk of cancer development. This study aimed to evaluate the level of radiation exposure experienced by pediatric patients undergoing a common CT examination at the three government hospitals in Addis Ababa, Ethiopia. Structured formats were designed for data collection at three government hospitals, and then information about pediatric patients' demography, CT protocols, and CT systems was retrieved and recorded from March 2018 up to July 2018. CT dose indicators: CTDIvol (mGy) and DLP (mGy.cm) values for abdomen, chest, and head CT scans were recorded based on pediatric patients' age ⩽1, (1-5], (5-10], and (10-15] years old. The data were analyzed through SPSS version 25 software. Finally, the third quartile values of CTDIvol and DLP were determined and compared with other international DRLs. The third quartile values of radiation dose descriptors for abdomen, chest, and head CT scans, respectively, in terms of CTDIvol (mGy): 58, 10, 17, 51; 23, 23, 34, 51; 62, 41, 50, 51; and in terms of DLP (mGy.cm), 377, 314, 624, 664; 523, 571, 406, 739; 927, 806, 929, and 1197 corresponded to pediatric patients of age ⩽1, (1-5], (5-10], and (10-15] years old, respectively. There were significant differences in the radiation dosage of some CT examinations between the same age groups, indicating a need for dose optimization. Therefore, this study recommends the need for enhancing radiation safety, ensuring appropriate imaging practices, and prioritizing the well-being of pediatric patients who visit CT examinations in Addis Ababa, Ethiopia.

Penentuan Nilai Diagnostic Reference Level (DRL) pada Pasien Abdomen menggunakan CT-Scan 128 di Instalasi RSUD A.W. Sjahranie Samarinda

Diagnostic Reference Level (DRL) is a form of investigative level used as a tool to help optimize protection in radiation exposure for diagnostic and interventional procedures. In simple terms, DRL is the amount of dose that is set and becomes a reference in identifying the reception of high radiation doses received by patients for certain types of examinations. DRL aims to optimize the use of radiation in medicine and help avoid overexposure to radiation. The purpose of this study was to determine the local DRL value on the examination of the abdomen at the Radiology Installation of A.W. Sjahranie Hospital Samarinda. Data processing in this study was carried out with quantitative analysis techniques, namely descriptive statistics. This analysis technique used secondary data obtained from the results of recaptures or archival books for examination of the abdomen. Data processing was carried out with a measure of diversity through the calculation of the third quartile (Q3) in the data distribution. It was assumed that 75% of patients performed examinations with a common diagnosis. The results of these calculations are visualized in the form of a graph of the relationship of CTDIvol with the number of patients and a graph of the relationship of DLP with the number of patients. In the abdomen examination, a CTDIvol value of 12 mGy and a DLP value of 1545.5 mGy.cm. The conclusion obtained from this study is the DRL value at A.W. Sjahranie Hospital Samarinda is relatively low, but it still needs to be optimized by medical physicists.

Establishing national clinical diagnostic reference levels and achievable doses for CT examinations in Brazil: A prospective study

PurposeDiagnostic reference levels (DRL) and achievable doses (AD) are important tools for radiation dose optimization. Therefore, a prospective study was performed which aimed to establish a multi-parametric, clinical indication based – DRL(DRLCI) and clinical indication – AD (ADCI) for adult CT in Brazil. MethodsThe prospective study included 4787 patients (50 ± 18 years old; male:female 2041:2746) at 13 Brazilian sites that have been submitted to head, paranasal sinus, cervical spine, chest, or abdomen-pelvis CT between January and October 2021 for 13 clinical indications. The sites provided the following information: patient age, gender, weight, height, body mass index[BMI], clinical indications, scanner information(vendor, model, detector configuration), scan parameters (number of scan phases, kV, mA, pitch) and dose-related quantities (CT dose index volume- CTDIvol, dose length product- DLP). Median(AD) and 75th(DRL) percentile CTDIvol and DLP values were estimated for each body region and clinical indications. Non-normal data were analyzed with the Kruskal-Wallis test. ResultsIn majority of Brazilian sites, body region and clinical indications based DRLs were at or lower than the corresponding DRLs in the US and higher than Europe. Although radiation doses varied significantly for patients in different body mass index groups (p < 0.001), within each body region, there were no differences in radiation doses for different clinical indications (p > 0.1). Radiation doses for 7/13 clinical indications were higher using iterative reconstruction technique than for the filtered back projection. ConclusionsThere was substantial variation in Brazil DRLCI across different institutions with higher doses compared to the European standards. There was also a lack of clinical indication-based protocol and dose optimization based on different clinical indications for the same body region.

Reduced versus standard dose contrast volume for contrast-enhanced abdominal CT in overweight and obese patients using photon counting detector technology vs. second-generation dual-source energy integrating detector CT

PurposeTo compare image quality of contrast-enhanced abdominal-CT using 1st-generation Dual Source Photon-Counting Detector CT (DS-PCD-CT) versus 2nd-generation Dual-Source Energy Integrating-Detector CT (DS-EID-CT) in patients with BMI ≥ 25, applying two different contrast agent volumes, vendor proposed protocols and different virtual monoenergetic images (VMI). Method68 overweight (BMI ≥ 25 kgm2) patients (median age: 65 years; median BMI 33.3 kgm2) who underwent clinically indicated, portal-venous contrast-enhanced abdominal-CT on a commercially available 1st-generation DS-PCD-CT were prospectively included if they already have had a pre-exam on 2nd-generation DS-EID-CT using a standardized exam protocol. Obesity were defined by BMI-calculation (overweight: 25–29.9, obesity grade I: 30–34.9; obesity grade II: 35–39.9; obesity grade III: > 40) and by the absolute weight value. Body weight adapted contrast volume (targeted volume of 1.2 mL/kg for the 1st study and 0.8 mL/kg for the 2nd study) was applied in both groups. Dual Energy mode was used for both the DS-PCD-CT and the DS-EID-CT. Polychromatic images and VMI (40 keV and 70 keV) were reconstructed for both the DS-EID-CT and the DS-PCD-CT data (termed T3D). Two radiologists assessed subjective image quality using a 5-point Likert-scale. Each reader drew ROIs within parenchymatous organs and vascular structures to analyze image noise, contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). ResultsMedian time interval between scans was 12 months (Min: 6 months; Max: 36 months). BMI classification included overweight (n = 10, 14.7 %), obesity grade I (n = 38, 55.9 %), grade II (n = 13, 19.1 %) and grade III (n = 7, 10.3 %). The SNR achieved with DS-PCD-CT at QIR level 3was 12.61 vs. 11.47 (QIR 2) vs. 10.53 (DS-EID-CT), irrespective of parenchymatous organs. For vessels, the SNR were 16.73 vs. 14.20 (QIR 2) vs. 12.07 (DS-EID-CT). Moreover, the obtained median noise at QIR level 3 was as low as that of the DS-EID-CT (8.65 vs. 8.65). Both radiologists rated the image quality higher for DS-PCD-CT data sets (p < 0.05). The highest CNR was achieved at 40 keV for both scanners. T3D demonstrated significantly higher SNR and lower noise level compared to 40 keV and 70 keV. Median CTDIvol and DLP values for DS-PCD-CT and DS-EID-CT were 10.90 mGy (IQR: 9.31 – 12.50 mGy) vs. 16.55 mGy (IQR: 15.45 – 18.17 mGy) and 589.50 mGy * cm (IQR: 498.50 – 708.25 mGy * cm) vs. 848.75 mGy * cm (IQR: 753.43 – 969.58 mGy * cm) (p < 0.001). ConclusionImage quality can be maintained while significantly reducing the contrast volume and the radiation dose (27% and 34% lower DLP and 31% lower CDTIvol) for abdominal contrast-enhanced CT using a 1st-generation DS-PCD-CT. Moreover, polychromatic reconstruction T3D on a DS-PCD-CT enables sufficient diagnostic image quality for oncological imaging.

Analisis Nilai CTDIvol Dan DLP Pada Pemeriksaan CT Scan Brain Non Kontras Dewasa Untuk Periode Januari – Desember 2022 Di Instalasi Radiologi Rumah Sakit X Jakarta Pusat

Background: CT scans are used for various types of examinations such as examinations of the head, thorax, abdomen and so on. The most frequently performed CT scan is a CT scan of the head. However, in the medical field, especially radiology, CT scans have the highest dose compared to other radiation equipment. Efforts to reduce radiation doses and radiation effects are by estimating the correct dose given to CT Scan patients using an optimization index called DRL (Diagnostic Level Reference), namely by evaluating the values ​​of CTDIvol and DLP on CT scans of the head, which have been determined in accordance with BAPETEN/I-DRL 2021 standards.&#x0D; Method: This research is a descriptive quantitative study with an observational approach which aims to analyze CTDIvol and DLP values ​​based on retrospective data on non-contrast brain CT scans at the Radiology Installation at Hospital X, Central Jakarta.&#x0D; Results: Calculation of the 2nd quartile (50th percentile) value of CTDIvol and DLP in Adult Non-Contrast Brain CT Scan examinations for the January-December 2022 Period at the Radiology Installation at X Hospital, Central Jakarta is CTDIvol 55.51 mGy and DLP 867.00 mGy* cm.&#x0D; Conclusion: The 50 percentile value of CTDIvol and DLP in the Adult Non-Contrast Brain CT Scan examination for the January-December 2022 period at the Radiology Installation at X Hospital, Central Jakarta is in accordance with the standards set by BAPETEN/I-DRL 2021. Where is the value for CT Non-Contrast Head Scan, namely a CTDIvol value of 60 mGy and a DLP value of 1275 mGy*cm.

ESTIMATION OF RADIATION DOSE AND ORGANS AT RISK (OAR) ON ABDOMINAL CT-SCAN USING SIZE-SPECIFIC DOSE ESTIMATES (SSDE) METHOD

A study has been carried out on the estimation of radiation dose and Organs at Risk (OAR) on abdominal CT-Scan examination using the SSDE method. The data used in this study were secondary data from medical records such as CTDIVol, DLP, and abdominal images of patients. This study aims to determine the size of SSDE, DE, and DEOAR and to determine whether DE is still within tolerance limits to ensure the feasibility of using CT-Scans in these installations. The SSDE value is obtained by multiplying the converted def value (f) and the CTDIVol, while the DE value is obtained by multiplying the DLP value and the conversion factor (k), finally, the DEOAR value is obtained by multiplying the CTDIVol and the organ/tissue weight factor. The results showed that the patient's average SSDE score was 12.04 ± 1.06 mGy, with a male SSDE value of 12.55 ± 1.30 mGy and a female SSDE value of 12.38 ± 2.47. While the average patient DEOAR value obtained was 7.57 ± 0.72 mGy and the patient's average DEOAR value for skin and bone surface was 0.09 ± 0.01 and red bone marrow and large intestine was 1.06 ±0.13. The DE value of this study is still below the tolerance value set by BAPETEN, which is less than 17.46 mGy.

Penentuan Dosis Efektif Pada Abdo Pelvis dan Organ Kritis dari Hasil Penyinaran Computed Tomography Scanner (CT Scan)

Determination of the effective dose on the abdo pelvis and organs at risk has been carried out from the results of the CT Scan irradiation at Sanglah General Hospital.The study began by collecting secondary data from the results of an abdominal CT scan, namely the CTDIvol and DLP values. Then the data was grouped based on gender of 40 patients with an age range of 20-70 years. The value of the effective dose in the abdo pelvis is obtained by multiplying the DLP value and the conversion coefficient k. While the effective dose to organs at risk is obtained from the product of the CTDIvol and wt. The results of the effective dose in the abdo pelvis were obtained in the range of 4.596-6.738 mSv for male patients while for female patients it was 4.209-5.232 mSv. The results of the effective dose in the abdo pelvis are still at the threshold set by BAPETEN, which is 13.275 mSv, so the CT scan is still suitable for use. Average effective dose values for critical organs were 0.2882 mSv for the liver, 0.8646 mSv for the kidney, and 0.5764 mSv for the gonad. The highest dose was received by the gonads. This shows that the gonads are the organs that have the highest sensitivity in receiving radiation doses in the abdo pelvis

Probability of induced cancers related to computed tomography examinations

Computed tomography (CT) is considered as one of the most used radiation imaging modalities, and CT procedures are increasing continuously all over the world, hence leading to considerable rise in cancers and radiation related diseases risk. This study was conducted in three general hospitals in Saudi Arabia, to analyze the associated radiation cancer risk from CT procedures. The collected data included the head chest, abdomen, abdomen pelvis (AP) and chest abdomen pelvis (CAP) procedures along with exposure parameter data (DLP and scan length). The risk of cancer was estimated by multiplying the effective dose with the risk coefficients obtained from ICRP 103. The mean DLP values were higher for females (647.5 ± 323.37 mGy cm) compared to male patients (587.7 ± 338.36 mGy cm), with no statistically significant differences (p = 0.497). The overall effective doses were 1.7 ± 0.53, 3.89 ± 1.22, 6.6 ± 4.23, 5.76 ± 3.28 and 10.75 ± 5.48 mSv for the head, chest, abdomen, abdomen pelvis (AP), and chest abdomen pelvis (CAP) procedures, respectively. The risk of cancer per procedure from head, chest, abdomen, AP and CAP procedures were found to be 6.96 × 10−5, 1.59 × 10−4, 2.71 × 10−4, 2.36 × 10−4, and 4.41 × 10−4, respectively. The effective doses and therefore the probability of cancer values were found to be within the range of other studies in the literature. However, dose optimization is always required, for the purpose of minimize the dose and cancer risk. Moreover, there is a clear need to improve awareness among radiology workers of unessential risks from suboptimal techniques in addition to applying the new imaging protocols in accordance with excellent practice around the world.

Analisis Diagnostic Reference Level (DRL) Pasien Pada Pemeriksaan Abdomen Kontras dan Nonkontras Dengan Pesawat CT Scan Di RSUD Bali Mandara

In this study, data were obtained from 35 patients aged 27-76 years. The current used varies from 46-185 mAs and a constant tube voltage of 130 kV, with different clinical symptoms. The patient's DRL value on contrast and non-contrast abdominal examination was determined by calculating the third quartile value. On non-contrast abdominal examination, the DRL CTDIvol value was 10.62 mGy and the DLP DRL was 607.76 mGy.cm and on the non-contrast abdominal examination, the DRL CTDIvol value was 32.73 mGy and the DRL DLP value was 1825.10 mGy.cm. These results indicate that the DRL CTDI vol and DRL DLP values on contrast abdominal examination at Bali Mandara Hospital were still below the actor's limits set by BAPETEN, while on abdominal examination the DRL CTDI vol and DRL DLP values exceeded the limits set by BAPETEN. This is caused by exposure which is done three times. Therefore, it is necessary to restore both the Patient Operational Standards (SOP) and the exposure factor on an abdominal contrast CT scan at Bali Mandara Hospital.

Ultra-High-Resolution CT of the Head and Neck with Deep Learning Reconstruction-Assessment of Image Quality and Radiation Exposure and Intraindividual Comparison with Normal-Resolution CT.

To assess the benefits of ultra-high-resolution CT (UHR-CT) with deep learning-based image reconstruction engine (AiCE) regarding image quality and radiation dose and intraindividually compare it to normal-resolution CT (NR-CT). Forty consecutive patients with head and neck UHR-CT with AiCE for diagnosed head and neck malignancies and available prior NR-CT of a different scanner were retrospectively evaluated. Two readers evaluated subjective image quality using a 5-point Likert scale regarding image noise, image sharpness, artifacts, diagnostic acceptability, and assessability of various anatomic regions. For reproducibility, inter-reader agreement was analyzed. Furthermore, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and slope of the gray-value transition between different tissues were calculated. Radiation dose was evaluated by comparing CTDIvol, DLP, and mean effective dose values. UHR-CT with AiCE reconstruction led to significant improvement in subjective (image noise and diagnostic acceptability: p < 0.000; ICC ≥ 0.91) and objective image quality (SNR: p < 0.000; CNR: p < 0.025) at significantly lower radiation doses (NR-CT 2.03 ± 0.14 mSv; UHR-CT 1.45 ± 0.11 mSv; p < 0.0001) compared to NR-CT. Compared to NR-CT, UHR-CT combined with AiCE provides superior image quality at a markedly lower radiation dose. With improved soft tissue assessment and potentially improved tumor detection, UHR-CT may add further value to the role of CT in the assessment of head and neck pathologies.

Effectiveness of body size stratification for patient exposure optimization in Computed Tomography

PurposeTo establish size-dependent DRL and to estimate the effectiveness of the size-dependent DRLs over size-independent DRLs for a CT exposure optimization process. MethodsThe study included 16,933 adult CT body examinations of the most common CT protocols. Acquisitions were included following an image quality assessment.Patients were grouped into five different classes by means of the water equivalent diameter (Dw): 21 ≤ Dw < 25, 25 ≤ Dw < 29, 29 ≤ Dw < 33,33 ≤ Dw < 37 (in cm). CTDIvol, DLP, DLPtot. and SSDE median values were provided both for the sample as a whole (size-independent approach) and for each Dw class (size-dependent approach).The performance of the two approaches in classifying sub-optimal examinations was evaluated through the confusion matrix and Matthews Correlation Coefficient (MCC) metric. The 75th percentile of the CTDIvol distribution was arbitrarily chosen as a threshold level above which the acquisitions are considered sub-optimal. ResultsCTDIvol, DLP, DLPtot and SSDE typical values (median values) are statistically different across Dw groups. The confusion matrix analysis suggests that size-independent DRL could not mark potential suboptimal protocols for small and large patients. The agreement between the size-dependent and size-independent methods is strong only for the most populous classes (MCC > 0.7). For small and large patients size-independent approach fails to identify as sub-optimal around 20 % of the acquisition (MCC≪0.2). ConclusionsIt was proven by means of the confusion matrix and MCC metric that stratifying DRLs by patient size, size-dependent DRL can be a powerful strategy in order to improve the dose optimization process shown that a size-independent DRL fails to identify sub-optimal examinations for small and large patients.

Establishment of national diagnostic dose reference levels (DRLs) for routine computed tomography examinations in Jordan

Abstract Background: Dose reference levels (DRLs) are used as indicators as well as guidance for dose optimization and to ensure justification of appropriate dose for a given clinical indication. The main aims of this study were to establish local DRLs for each CT imaging protocol as a reference point to evaluate the radiation dose indices and to compare our DRLs with those established in other countries and against the internationally reported guidelines. Materials and methods: 2000 CT dose reports of different adult imaging protocols from January 2021 until April 2022 were collected retrospectively at different hospitals in Jordan. Data were collected from CT scans that were performed using different types and models of CT scanners and included four adult non-enhanced, helical CT imaging protocols; Head, Chest, Abdomen-Pelvis, and Chest-Abdomen-Pelvis. Results: The average doses of CTDIvol, DLP, and effective dose were (65.11 mGy, 1232.71 mGy·cm, 2.83 mSv) for the head scan, (16.6 mGy, 586.6 mGy·cm, 8.21 mSv) for the chest scan, (17.91 mGy, 929.9 mGy·cm, 13.9 mSv) for the abdomen-pelvis scan, and (19.3 mGy, 1152 mGy·cm, 17.25 mSv) for the chest-abdomen-pelvis scan. In comparison with results from different international studies, DLP values measured in the present study were lower for the chest-abdomen-pelvis and abdomen-pelvis CT scans, and higher for the head CT and chest CT scans. Conclusions: It is very important that each country establishes its own DRLs and compares them with those reported by other countries, especially the developed ones. It is also important that these levels are regularly updated.

Assessment of Organ Dose and Effective Dose from Head Computed Tomography in Northwestern Nigeria

The amount of radiation dose received by patient undergoing Head computed tomography examination in General Amadi rimi orthopedics and specialist hospital, Katsina has been estimated. Computed tomography dose output was used to determine the effective dose and organ dose of non-contrast to the head region of 30 patients. The tube potential ranged from 127 kVp to 130 kVp, while the mAs ranged from 130 mAs to 140. The aims of this study are, first, to assess the mean effective doses received by patients undergoing Head CT examinations and compare them with other studies. Mean values of CTDIvol. was (43.1mGy), the mean DLP values was (1206 mGy.cm), the mean effective dose (HEDLP) value was (2.4 mSv). The result was compared with the European Union reference dose level and other published factor. HEDLP was slightly higher than the values reported from the literature for the united nation and European union report by 0.4 factor. It was concluded that patient organ doses could be substantially minimized, optimized and justified. The high variation in the doses in this study may be due to differences in imaging protocols such as large range of mAs and scan length and also algorithms of the scanner.