Mean Effective Dose Research Articles

MP53-20 PREDICTING SURVIVAL OUTCOMES AFTER BRACHYTHERAPY USING THE AUA AND PHOENIX DEFINITION OF BIOCHEMICAL FAILURE

You have accessJournal of UrologyProstate Cancer: Localized: Radiation Therapy (MP53)1 Apr 2020MP53-20 PREDICTING SURVIVAL OUTCOMES AFTER BRACHYTHERAPY USING THE AUA AND PHOENIX DEFINITION OF BIOCHEMICAL FAILURE Zeynep G. Gul*, Rollin K. Say, Shirin Razdan, and Nelson N. Stone Zeynep G. Gul*Zeynep G. Gul* More articles by this author , Rollin K. SayRollin K. Say More articles by this author , Shirin RazdanShirin Razdan More articles by this author , and Nelson N. StoneNelson N. Stone More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000915.020AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Biochemical failure (BF) after radiation therapy is defined by the Phoenix definition as the nadir PSA +2. After radical prostatectomy, the AUA definition of BF is a PSA >0.2. The objective of the current study was to compare the AUA and Phoenix definitions of BF as predictors of distant metastasis (DM) and overall survival (OS). METHODS: 2319 men with T1-T4N0M0 prostate cancer were treated with brachytherapy. The mean follow-up was 105 months (8.75 years) and the mean biological effective dose (BED) was 195. Cox regression analysis were performed to determine the associations of AUA BF and Phoenix BF on DM and OS. The other variables included in the analysis were total BED, initial PSA, age at diagnosis, Gleason Score (6 vs 7-10), and clinical stage (T1/T2 vs T3/T4). RESULTS: BF occurred in 413 (17.8%) and 260 (11.2%) men according to the AUA and Phoenix definition, respectively. DM were seen in 71 patients (3.1%). 449 men (19.4%) died during follow up and 65 (2.8%) died from prostate cancer. Both the AUA and Phoenix definitions were significantly associated with DM and OS. CONCLUSIONS: The AUA and Phoenix definitions of BF are similar in their ability to predict DM and OS. Using the AUA definition would allow for better comparisons of outcomes following radical prostatectomy and brachytherapy. Source of Funding: None © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e790-e790 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Zeynep G. Gul* More articles by this author Rollin K. Say More articles by this author Shirin Razdan More articles by this author Nelson N. Stone More articles by this author Expand All Advertisement PDF downloadLoading ...

Comparison of the Effectiveness of Single-Component and Multicomponent Interventions for Reducing Radiation Doses in Patients Undergoing Computed Tomography

Computed tomography (CT) radiation doses vary across institutions and are often higher than needed. To assess the effectiveness of 2 interventions to reduce radiation doses in patients undergoing CT. This randomized clinical trial included 864 080 adults older than 18 years who underwent CT of the abdomen, chest, combined abdomen and chest, or head at 100 facilities in 6 countries from November 1, 2015, to September 21, 2017. Data analysis was performed from October 4, 2017, to December 14, 2018. Imaging facilities received audit feedback alone comparing radiation-dose metrics with those of other facilities followed by the multicomponent intervention, including audit feedback with targeted suggestions, a 7-week quality improvement collaborative, and best-practice sharing. Facilities were randomly allocated to the time crossing from usual care to the intervention. Primary outcomes were the proportion of high-dose CT scans and mean effective dose at the facility level. Secondary outcomes were organ doses. Outcomes after interventions were compared with those before interventions using hierarchical generalized linear models adjusting for temporal trends and patient characteristics. Across 100 facilities, 864 080 adults underwent 1 156 657 CT scans. The multicomponent intervention significantly reduced proportions of high-dose CT scans, measured using effective dose. Absolute changes in proportions of high-dose scans were 1.1% to 7.9%, with percentage reductions in the proportion of high-dose scans of 4% to 30% (abdomen: odds ratio [OR], 0.82; 95% CI, 0.77-0.88; P < .001; chest: OR, 0.92; 95% CI, 0.86-0.99; P = .03; combined abdomen and chest: OR, 0.49; 95% CI, 0.41-0.59; P < .001; and head: OR, 0.71; 95% CI, 0.66-0.76; P < .001). Reductions in the proportions of high-dose scans were greater when measured using organ doses. The absolute reduction in the proportion of high-dose scans was 6.0% to 17.2%, reflecting 23% to 58% reductions in the proportions of high-dose scans across anatomical areas. Mean effective doses were significantly reduced after multicomponent intervention for abdomen (6% reduction, P < .001), chest (4%, P < .001), and chest and abdomen (14%, P < .001) CT scans. Larger reductions in mean organ doses were 8% to 43% across anatomical areas. Audit feedback alone reduced the proportions of high-dose scans and mean dose, but reductions in observed dose were smaller. Radiologist's satisfaction with CT image quality was unchanged and high during all periods. For imaging facilities, detailed feedback on CT radiation dose combined with actionable suggestions and quality improvement education significantly reduced doses, particularly organ doses. Effects of audit feedback alone were modest. ClinicalTrials.gov Identifier: NCT03000751.

Evaluation of Patient's Dose and Estimate of Cancer Risk in Electrophysiology Studies and Ablation in Cath Lab Center of Afshar Hospital, Yazd, Iran

Introduction: Today electrophysiology studies and ablation have been developed due to increasing arrhythmias disorder of heart. In these diagnostic – treatments methods, the use of fluoroscopy can be causes patient radiation dose, therefore evaluation of patient's absorbed dose is necessary to protection of the radiation. The aim of this study was to evaluate the absorbed dose in patients undergoing electrophysiology and cardiac ablation and to estimate their risk of cancer in Yazd Afshar Hospital. Methods: This study was a cross-sectional study. In this study, the mean absorbed dose of referral patients for electrophysiology studies and ablation had been measured in the cat. Lab of Afshar Hospital, Yazd. The dosimeter had been used in this research was KAP meter, the M4 DIAMENTOR made in Germany that was able to measure dose-area product and time of the fluoroscopy. The patient effective dose was calculated by the PCXMC software from dose-area product. Results: The mean dose-area in ablation and electrophysiology studies was respectively 153.34±105.32 and 5.62 14.88 Gy.cm2 and the radiation time range was recorded 3.32 to 68.65 minutes and 1.03 to 6.28 minutes, respectively. The mean effective dose of ablation and electrophysiology studies were respectively 16.38 and 1.65 mSv. The cancer risk per ten thousands of patients, who were under the ablation and electrophysiology examinations were estimated 13 and 1.3 people, respectively. Conclusion: Increasing of patient dose due to ablation in this study relation to the other studies can be due to long old of image intensifier device.

Organ Doses, Effective Dose, and Cancer Risk From Coronary CT Angiography Examinations.

OBJECTIVE. The purposes of this study were to determine organ and effective doses and to estimate the risk of exposure-induced cancer death (REID) associated with coronary CT angiography (CCTA) examinations. SUBJECTS AND METHODS. CCTA examinations were performed in three stages: calcium score, monitoring, and cardiac phases for all patients. Effective dose was calculated using two methods. The first was based on the scanner-derived dose-length product, and the second entailed use of an organ and effective dose calculator software application. Organ doses were calculated on the basis of the tissue weighting factors of International Commission on Radiation Protection report 103. REID values were assessed with a cancer risk estimator software application. RESULTS. The study included 185 patients (95 men, 90 women). For women, breast doses were high at 52.04 ± 14.08 mGy. The mean effective dose in the women was greater than that in the men (24.05 vs 16.30 mSv, p < 0.05). The mean REID values in patients undergoing CCTA with a 64-MDCT scanner were 13.4 per 10,000 men (1 in 746) and 19.6 per 10,000 women (1 in 508). The REID values were considerably higher for the younger women. CONCLUSION. The results of this study will help referring physicians justify requesting CCTA examinations by considering their benefits for diagnosis on the one hand and awareness of the risk of radiation-induced cancer on the other. In the case of CCTA scans that are properly justified by clinical indication, patients and physicians should not be concerned about the radiation risks.

Evaluation of the Portuguese population exposure to ionizing radiation due to x-ray and nuclear medicine procedures from 2013 to 2017

This work provides an estimation of the exposure of the Portuguese population to ionizing radiation due to radiodiagnostic (x-ray and nuclear medicine (NM)) procedures, between 2013 and 2017, using the methodology proposed by the European Commission. Obtained results show that the estimated annual mean effective dose to the Portuguese population due to x-ray procedures increased by about 16%, from 0.75 ±0.48 mSv per caput in 2013 to 0.89 ±0.56 mSv per caput in 2017. The x-ray exam type that contributes the most to the collective dose in Portugal is Computed Tomography (CT). In the case of nuclear medicine, an increase in the annual effective dose from 0.088 ±0.001 mSv per caput in 2013 to 0.090 ±0.002 mSv per caput in 2017 was observed, with the procedures that contribute the most to the collective dose being bone imaging and cardiac procedures. This study intends to raise awareness to the need of optimization of radiation dose in medical procedures.

Diagnostic value of low dose dual-source CT cerebral perfusion imaging in patients with hyperacute cerebral infarction

Objective To evaluate image quality and radiation dosage of CT cerebral perfusion (CTP) imaging of 70 kV with different tube current and scanning passes and its diagnostic value for hyperacute cerebral infarction. Methods A total of 190 patients with suspected hyperacute cerebral infarction in Lishui Central Hospital of Zhejiang Province from December 2017 to February 2019 were selected prospectively, and all patients were divided into 4 groups according to random number table and received non-contrast CT examination and dual-source CT cerebral perfusion imaging with 70 kV protocol simultaneously within 6 hours after the onset of symptoms: group A, 120 mA, 21 scanning time points; group B, 100 mA, 21 scanning time points; group C, 100 mA, 17 scanning time points; group D, 80 mA, 21 scanning time points. The values of perfusion parameters such as cerebral blood flow (CBF), crerbral blood volume (CBV), mean transit time (MTT), time to peak (TTP) were acquired. Image quality was evaluated and effective dose (ED) was recorded. The quantitative variables of image quality and radiation dosage were compared between four groups using one-way analysis of variance test. Results There was no differences between groups on the CBF, CBV, MTT, TTP maps for all CTP values (P>0.05), and all images could meet the diagnostic requirements. The subjective image quality score of vessel sharpness and overall image quality of both internal carotid artery and middle cerebral artery and the degree of noise of internal carotid in artery in group A was higher than that in group D (P<0.05). The score of vessel sharpness of internal carotid in artery ingroup A was higher than those in both groups B and C (P<0.05). The scores of vessel sharpness of both internal carotid artery and middle cerebral artery internal carotid in artery ingroups B and C were higher than that in group A (P<0.05). The mean EDs of non-contrast CT in group A, B, C, D were 1.10, 2.11, 1.76, 1.42, 1.40 mSv; compared to group A, ED was reduced approximately 16.6% (0.35/2.11), 32.7% (0.69/2.11) and 33.6% (0.71/2.11), respectively (P<0.05). The diagnostic accuracy of low dose dual source CTP for detecting hyperacute cerebral infarction was 93.5% (172/184), while that of non-contrast CT was 52.2% (96/184);for detecting hyperacutelacunar cerebral infarction, it was 72.1% (31/43) and 16.3% (7/43) respectively (P<0.05). Conclusion Appropriate reduction of tube current (100 mA) and scanning passes (17 scanning time points) can reduce the radiation dosage and acquire comparable image quality for 70 kV protocol CTP. Compared with non-contrast CT, low dose dual-source CTP is more sensitive to hyperacute cerebral infarction, especially hyperacute lacunar cerebral infarction. Key words: Cerebral infarction; Radiation dosage; Tomography, X-ray computed

Study of the anti-inflammatory effect of the combined extract BNO 1016 in a leukotriene-dependent in vivo inflammation model

A significant role in the pathogenesis of rhinosinusitis is played by an inflammatory reaction in the maxillary sinuses of the nasal cavity. Leukotrienes are the most powerful mediators of inflammation, especially at the early stages. The effect of combined dry extract BNO 1016 could be useful for the inhibition of the inflammation in rhinosinusitis. Thus, it appears reasonable to study the anti-inflammatory activity of the combined dry extract BNO 1016.Materials and methodsThe tested drug is the combined dry extract BNO 1016 produced by “Bionorica SE”. The reference drug is Ibuprofen. Leukotriene inflammation was induced by subplantar injection of zymozan into the right hind paw of male and female Wistar rats. Volumes of the resulting edema were measured and levels of anti-inflammatory activity together with mean effective dose (ED50) were calculated.ResultsThe highest anti-inflammatory activity was observed at a dose level of 500 mg/kg of BNO 1016 during all time-points of the experiment and reached 65.2% 2 h after induction of inflammation. The anti-inflammatory activity of BNO 1016 at 500 mg/kg was credibly higher than that of Ibuprofen at all time-points of the experiment. Based on the data obtained from this leukotriene-dependent inflammation experiment the mean effective dose (ED50) for anti-inflammatory activity of dry combined extract BNO 1016 was calculated with help of Probit analysis.ConclusionThe combined dry extract BNO 1016 shows a high level of anti-inflammatory activity in leukotriene-dependent inflammation which is very promising for the improvement of the treatment of patients. However, additional preclinical and clinical research on this drug should be carried out.

Ultra-low-dose computed tomography for attenuation correction of cadmium-zinc-telluride single photon emission computed tomography myocardial perfusion imaging

BackgroundThe applicability of ultra-low-dose computed tomography (CT) for attenuation correction (AC) of single-photon-emission computed tomography myocardial perfusion imaging (SPECT-MPI) remains elusive. Methods and resultsOne-hundred patients underwent one-day 99mTc-tetrofosmin stress-rest MPI and non-contrast enhanced cardiac CT with 120, 80, and 70 kilovolt peak (kVp) tube voltage and tube current of 200 milliamperes for creation of AC maps. Normalized percent myocardial uptake from SPECT-MPI using 80 kVp scans for AC showed excellent correlation vs AC from 120 kVp scans for stress [intraclass correlation (ICC) = 0.988, 95% CI = 0.986-0.989, P < .001] and rest (ICC = 0.985, 95% CI = 0.983-0.987, P < .001) with narrow Bland-Altman limits of agreement (BA-LA) (− 5.3% to 4.5% and − 5.4% to 4.4%, respectively) and minimal bias (− 0.4% and − 0.5%, respectively). Correlation of AC SPECT-MPI based on 70 vs 120 kVp scans was excellent for stress (ICC = 0.988, 95% CI = 0.986-0.989, P < .001) and rest (ICC = 0.986, 95% CI = 0.984-0.987, P < .001) with narrow BA-LA (− 5.3% to 4.4% and − 5.2% to 4.5%, respectively) and small bias (− 0.4% and − 0.3%, respectively). Mean effective radiation dose for the 120, 80 and 70 kVp scans were 0.58 ± 0.07, 0.19 ± 0.02, and 0.12 ± 0.01 mSv, respectively. ConclusionsAttenuation maps for MPI obtained from ultra-low radiation dose CT scans are interchangeable with attenuation maps from standard-dose CT while offering a substantial reduction in radiation dose exposure.

Substantial radiation dose reduction with consistent image quality using a novel low-dose stone composition protocol.

To assess a novel low-dose CT-protocol, combining a 150kV spectral filtration unenhanced protocol (Sn150kVp) and a stone-targeted dual-energy CT (DECT) in patients with urolithiasis. 232 (151 male, 49 ± 16.4years) patients with urolithiasis received a low-dose non-contrast enhanced CT (NCCT) for suspected urinary stones either on a third-generation dual-source CT system (DSCT) using Sn150kVp (n = 116, group 1), or on a second-generation DSCT (n = 116 group 2) using single energy (SE) 120kVp. For group 1, a subsequent dual-energy CT (DECT) with a short stone-targeted scan range was performed. Objective and subjective image qualities were assessed. Radiation metrics were compared. 534 stones (group 1: n = 242 stones; group 2: n = 292 stones) were found. In group 1, all 215 stones within the stone-targeted DECT-scan range were identified. DE analysis was able to distinguish between UA and non-UA calculi in all collected stones. 11 calculi (5.12%) were labeled as uric acid (UA) while 204 (94.88%) were labeled as non-UA calculi. There was no significant difference in overall Signal-to-noise-ratio between group 1 and group 2 (p = 0.819). On subjective analysis both protocols achieved a median Likert rating of 2 (p = 0.171). Mean effective dose was significantly lower for combined Sn150kVp and stone-targeted DECT (3.34 ± 1.84mSv) compared to single energy 120kVp NCCT (4.45 ± 2.89mSv) (p < 0.001), equaling a 24.9% dose reduction. The evaluated novel low-dose stone composition protocol allows substantial radiation dose reduction with consistent high diagnostic image quality.

Comparison of image quality and focal lesion detection in abdominopelvic CT: Potential dose reduction using advanced modelled iterative reconstruction

PurposeTo evaluate radiation dose exposure, diagnostic performance, and image quality of low-dose and ultralow-dose abdominopelvic CT using the advanced modelled iterative reconstruction (ADMIRE) algorithm for focal lesion detection. MethodsOne hundred thirty-nine consecutive patients underwent contrast-enhanced abdominopelvic CT using a third-generation dual-source scanner to obtain three data sets with the following tube loads: 33.3% (ultralow-dose CT), 66.7% (low-dose CT), and 100% (standard-dose CT). The diagnostic performances of standard-dose CT, low-dose CT, and ultralow-dose CT for focal lesion detection and characterization in organs of the abdominopelvic cavity were analyzed by two readers and compared with the reference standard. Image quality was measured subjectively and objectively. ResultsFocal lesion detection showed 96.5–100% sensitivity and 97.7–100% accuracy in all representative organs on low-dose CT with acceptable image quality; it showed 87.4% sensitivity and 97.9% accuracy in the liver and 80.0% sensitivity and 88.2% accuracy in the rectal shelf on ultralow-dose CT with suboptimal image quality. Indeterminate lesions were significantly more common in the liver, pancreas, and kidneys on ultralow-dose CT than on low-dose CT. Enlarged lymph nodes showed 100% sensitivity and accuracy on ultralow-dose CT. Mean effective radiation doses of low-dose CT and ultralow-dose CT were 2.6 mSv and 1.3 mSv, respectively. ConclusionsThe diagnostic performance of low-dose CT is similar to that of standard-dose abdominopelvic CT with acceptable image quality. Ultralow-dose CT cannot safely assess focal liver, pancreas, kidneys, and rectal shelf lesions but may be useful for the evaluation of enlarged lymph nodes.

Ultra-Low-Dose CT: An Effective Follow-Up Imaging Modality for Ureterolithiasis.

Background and Purpose: Classically, abdominal X-ray (KUB), ultrasound, or a combination of both have been routinely used for ureteral stone surveillance after initial diagnosis. More recently, ultra-low-dose CT (ULD CT) has emerged as a CT technique that reduces radiation dose while maintaining high sensitivity and specificity for urinary stone detection. We aim to evaluate our initial experience with ULD CT for patients with ureterolithiasis, measuring real-world radiation doses and stone detection performance. Methods: We reviewed all ULD CT scans performed at the Veterans Affairs Palo Alto Health Care System between 2016 and 2018. We included patients with ureteral stones and calculated the mean effective radiation dose per scan. We determined stone location and size, if the stone was visible on the associated KUB or CT scout film, and if hydronephrosis was present. We performed logistic regression to identify variables associated with visibility on KUB or CT scout film and hydronephrosis. Results: One hundred eighteen ULD scans were reviewed, of which 50 detected ureteral stones. The mean effective radiation dose was 1.04 ± 0.41 mSv. Of the ULD CTs that detected ureterolithiasis, 38% lacked visibility on KUB/CT scout film and had no associated hydronephrosis, suggesting that they would be missed with a combination of KUB and ultrasound. Larger stones (odds ratio [OR]: 1.40, 95% confidence interval [CI]: 1.08, 1.96 for every 1 mm increase in stone size) were more likely to be detected by KUB/CT scout film or ultrasound, while stones in the distal ureter (OR: 0.18, 95% CI: 0.03, 0.81) were more likely to be missed by KUB/CT scout film or hydronephrosis. Conclusions: Based on our institutions' initial experience, ULD CT detects small and distal ureteral stones that would likely be missed by KUB or ultrasound, while maintaining a low effective radiation dose. An ULD CT protocol should be considered when reimaging for ureteral stones is necessary.

Trends in the doses of the population of the Russian Federation in 2003–2018

In the last years radiation-hygienic passportization and Joint state system of control and accounting of the individual doses of the citizens have become a trusted source of the validated data on the state of the radiation safety in the Russian Federation and have become the basis of the Russian system of the information provision of the radiation safety. Annual analysis of that data is presented in the annual information bulletin “Doses of the population of the Russian Federation”. The current study is focused on the analysis of the data from the information bulletins to evaluate the trends in the doses of the Russian population from main sources of ionizing exposure in 2003–2018. It is indicated that the mean annual doses from man-made exposure of the group A staff in that period varies from 1,0–1,4 mSv per year, group B – 0,65–0,8 mSv per year. The number of exceedances of the annual dose limits from group A staff varied from 5 to 52 per year; for group B – 0–22 per year. For the whole investigated period there were only three cases of the exceedance of the 50 mSv annual individual dose for group A staff and four cases of the exceedance of the 12,5 mSv annual effective dose for group B staff. Mean effective dose per X-ray examination in 2006–2013 was decreasing from 0,56 mSv to 0,26 mSv and started to slowly increase leading to 0,29 mSv in 2018. The same trends were identified for the mean dose from medical exposure per citizen: reduction in 2003-2013 from 0,86 mSv to 0,45 mSv with the subsequent increase up to 0,56 mSv. The biggest contributor for the dose from medical exposure is computed tomography: the number of CT examinations increased from 1,3 mln in 2003 to 11,7 mln in 2018; contribution to the collective dose – from 5,7% to 54%. Mean annual effective doses from natural exposure of the population of the Russian regions varied from 1,6 to 15,1 mSv per year with the mean value for Russia of 3,11 – 3,79 mSv/year. The highest mean annual doses exceeding 5 mSv in each year were observed in Republic of Altay, Jewish Independent Region, Stavropol and Zabaikalskiy Krai, Republic of Tyva and Irkutsk region. Total effective doses exceeding 10 mSv/year were observed in Republic of Altay and Jewish Independent Region. For ten subjects of the Russain Federation (Republics of Buryatia, Altay, Tyva, Stavropol and Zabaikalskiy Krai, Irkutsk and Chita regions, Jewish Independent Region, Aginsko-Buryatskiy and Ust’-Ordinskiy independent districts) they exceed 5 mSv/year for the whole assessed period.

ЕКСПЕРИМЕНТАЛЬНЕ ВИЗНАЧЕННЯ ЕФЕКТИВНОЇ ДОЗИ (ЕД50) СУХИХ ЕКСТРАКТІВ ЛИСТЯ ТА КОРЕНЕВИЩ IRIS HUNGARICA З ПОТЕНЦІЙНИМИ АНАБОЛІЧНИМИ ВЛАСТИВОСТЯМИ

Keywords: effective dose, anabolic activity, extract, hungarian iris. Acknowledging the importance of plants in the correction of negative nitrogen balance and mild to moderate muscular atrophy, the following advantages of herbal medicinal products over synthetic drugs were taken into account: optimal bioavailability at the systemic, organ and cellular levels; biochemical digestibility of intermediate and end products of metabolism, which decreases the probability of accumulation significantly; organotropic, allergenic and toxic action. The study objective was to determine ED50 values of Iris hungarica leaf and rhizome dry extracts by application of the least square method to the anabolic activity in the intact animals. The study was conducted in 72 white outbred male rats, weighing 230 to 240 g. The anabolic activity of the extracts is estimated by the following indicators: body weight gain of animals; relative weight of internal organs – heart, gastrocnemius muscle, testes; total protein in blood serum, gastrocnemius and cardiac muscles. The experimental animals were administered extracts in doses of 50 mg/kg, 100 mg/kg, 150 mg/kg, 200 mg/kg, 250 mg/kg, and 300 mg/kg. The mean effective dose was 148.81±23.91 mg/kg for Iris hungarica dry leafextract, and 147.27±26.11 mg/kg for Iris hungarica dry rhizome extract as determined by signs of the anabolic effect in the intact animals. Thus, the presence of anabolic effect in dry extracts of leaves and rhizomes of Hungarian iris shows the potential of herbal medicinal products, and the need for more pharmacological studies in order to create a new medicinal product for the correction of negative nitrogen balance and mild to moderate muscular atrophy.

Estimation of Absorbed and Effective Doses in Organs through Computed Tomography Examinations Using Automatic Exposure Control and Fixed Tube Current Techniques: A Phantom Case Study

Introduction: The study aimed to assess absorbed and effective doses in organs through computed tomography (CT) examinations using automatic exposure control (AEC) and fixed tube current (FTC) techniques. Material and Methods: Scanning parameters were obtained for routine adult CT examinations and used to estimate the organ absorbed and effective doses using CT-Expo software. The estimated effective doses were based on International Commission on Radiological Protection publication 103 recommendations. Results: Regarding the scans performed with AEC, doses to head, chest, abdomen and pelvic organs were within the range of 19.7-41.8, 6.4-17.4, 19.2-20.9, and 10.5-24.9 mGy respectively. Moreover, the effective doses for the mentioned organs were 1.6, 6.1, 6.4 and 5.4 mSv respectively. Considering FTC technique, doses to organs ranged 16.7-75.5, 4.1-52.2, 10.6-33.2 and 5.2-38.7 mGy respectively. Moreover, the mean effective doses of FTC were 2.1, 6.9, 9.4 and 6.1 mSv, respectively. Examinations performed with AEC technique induced a dose reduction of 9% and 34% for head organs, 52, 62 and 25% for chest organs, 16% and 14% for abdomen organs, and 11% and 10% for pelvic organs, compared to the FTC. A dose increase of 3% was observed for testes. The mean effective doses for scans with AEC were 13-46% lower than those obtained by FTC. Conclusion:According to the obtained results of the current study, the estimated doses for scans with AEC technique were in a lower level compared to FTC technique. Accordingly, it is recommended to utilize this technique for CT examinations to ensure optimal dose reduction to radiosensitive organs.

Assessment of radiation doses received by patients during endoscopic retrograde cholangiopancreatography according to disease location.

patients are exposed to ionizing radiation during endoscopic retrograde cholangiopancreatography (ERCP). Radiation dose depends on multiple factors. The goal of this study was to assess fluoroscopy time (FT), radiation doses and effective dose (ED) during ERCP according to the condition being treated. a descriptive study was performed of 369 consecutive ERCPs from January 2017 to June 2019. Patient demographic and procedure data were collected. FT, cumulative dose area product (DAP), fluoroscopy DAP, DA fluoroscopy, air kerma, and number of radiographs were assessed. ED was estimated using specific conversion factors. the mean age was 73.34 years and 193 subjects were male. Mean FT was 4.56 ± 0.17 min, cumulative DAP was 2,056.73 ± 188.83 cGycm2, fluoroscopy DAP was 1,722.90 ± 82.26 cGycm2 and air kerma was 85.84 ± 4.93 mGy. The number of radiographs was 2.10 ± 0.07 and the mean ED was 5.34 ± 0.49 mSv. FT was significantly longer for choledocholithiasis (CL), proximal malignant biliary stricture (PMBS) and distal malignant biliary stricture (DMBS) versus others (OT). Cumulative DAP was higher for PMBS (p < 0.002). FT, cumulative DAP, fluoroscopy DAP and air kerma values were significantly higher for complicated CL as compared to simple CL. ED was higher for CL, DMBS and PMBS, but only significantly (p < 0.002) for PMBS. FT for ERCP is variable and increases with exploration difficulty. Thus, it is longer in the case of PMBS, as well as with the amount of radiation received by the patients and ED.

Assessment of Diagnostic Reference Dose Associated with Computed Tomography Examination

The current study is aimed to estimate the diagnostic reference dose levels (DRLs), the volume computer tomogram dose index (CTDIvol), the CT air kerma-length product (PKL,CT) and the effective dose (E) for head, chest and chest-abdomen-pelvic CT examinations performed on adults in King Abdullah Medical City (KAMC), Saudi Arabia. Demographic parameters (such as age, gender, weight, height) for a sample of 535 computed tomography (CT) patients and physical scan parameters (such as patient tube voltage (kV), reference and effective mill ampere-second (mAs), scan length, number of slices, and pitch factor) were collected from a picture archiving and communication system (PACS). CTDIvol and PKL,CT were studied for different patients weights (40 -60 kg, 60-80 kg, 80-100 kg and 100-120 kg). Mean CTDIvol, PKL,CT and effective dose for a standard weight (70 kg ±10%) was evaluated according to the three CT protocols considered and the results were, as follows: for head examinations – 61.8 mGy, 1212 mGy.cm and 2.55 mSv, respectively; for chest examinations- 13.1 mGy, 657.5 mGy.cm and 9.21 mSv, respectively; for chest-abdomen-pelvic examinations - 13.9 mGy, 782.5 mGy.cm and 11.73 mSv, respectively. The effective dose for the chest examinations was lower than the corresponding value communicated by the European study group under European Commission. The effective dose for head examinations, was slightly higher than the one communicated by the European Commission study due to differences in the scan length. It needs optimizing the radiation dose delivered to patients via periodical review of scan parameters for a protocol under study.

Ultra‐low‐dose chest computed tomography without anesthesia in the assessment of pediatric pulmonary diseases

ObjectiveTo evaluate the feasibility of using ultra‐low‐dose computed tomography of the chest with iterative reconstruction without anesthesia for assessment of pulmonary diseases in children. MethodsThis prospective study enrolled 86 consecutive pediatric patients (ranging from 1 month to 18 years) that underwent ultra‐low‐dose computed tomography due to suspicion of pulmonary diseases, without anesthesia and contrast. Parameters used were: 80kVp; 15–30mA; acquisition time, 0.5s; and pitch, 1.375. The adaptive statistical iterative reconstruction technique was used. Subjective visual evaluation and quantitative assessment of image quality were done using a 5‐point scale in 12 different structures of the chest. ResultsMean age was 66 months (interquartile range, 16–147). Final diagnosis was performed in all exams, and 44 (51.2%) were diagnosed with cystic fibrosis, 27 (31.4%) with bronchiolitis obliterans, and 15 (17.4%) with congenital pulmonary airways malformations. Diagnostic quality was achieved in 98.9%, of which 82.6% were considered excellent and 16.3% were slightly blurred but did not interfere with image evaluation. Only one case (1.2%) presented moderate blurring that slightly compromised the image, and previous examinations demonstrated findings compatible with bronchiolitis obliterans. Mean effective radiation dose was 0.39±0.15mSv. Percentages of images with motion artifacts were 0.3% for cystic fibrosis, 1.3% for bronchiolitis obliterans, and 1.1% for congenital pulmonary airways malformations. ConclusionChest ultra‐low‐dose computed tomography without sedation or anesthesia delivering a sub‐millisievert dose can provide image quality to allow identification of common pulmonary anatomy and diseases.

Occupational dose during an interventional radiology procedure

The development of radiation utilization, in medical application, increases every year. One of them was the interventional radiology facility. Interventional radiology has been chosen to replace invasive procedures for diagnosing and cure several cases of the blood system. However large radiation exposure for radiation workers remains the main potential of an occupational hazard. Therefore, radiation protection plays an important role in ensuring the occupational dose does not exceed the regulated limits by BAPETEN. The purpose of this study was to determine the estimated effective dose (mSv) received by radiation workers undergoing interventional procedures. Occupational doses were measured using the thermoluminescence dosimeter (TLD) chips which placed on critical organ areas such as thyroid, thorax and gonads / ovaries during interventional procedures. In this study, the interventional procedures carried out for PCI, embolization, PTCA, limb intervention, thoracic intervention and cerebral intervention. The TLD was then read using the TLD Reader 3500 Harshaw. The results of this study showed mean effective dose received by doctors, nurses and radiographers in several hospitals in Indonesia due to carrying out interventional procedures was 0.043 ± 0.034, 0.048 ± 0.064 and 0.047 ± 0.031, respectively. The dose received by the radiation worker is still below the limit regulated by BAPETEN, which is 20 mSv / year. These doses were varied based on the type of interventional procedure and the time of fluoroscopy.

A radiological index for evaluating the impact of an abandoned uranium mining area in Salamanca, Western Spain

The establishment of a screening index would be a powerful tool to decide whether abandoned uranium mining areas should be rehabilitated or decommissioned. Thus, in this work we established a radiological index which uses the activity concentrations of different groups of gamma emitters from the natural radioactive series of 238U, 235U, and 232Th, as well as 40K and 137Cs. These activity concentrations were calculated by using the absorbed gamma radiation dose value of 175 nGy h−1 specified in the U.S. Code of Federal Regulations. We studied our index in an abandoned uranium mining area in Salamanca, Western Spain, and found that the most influential factors in this area were the presence of organic matter in the soil and the possible effect that plants and fungi may have on the retention of these aforementioned radionuclides. In addition, the results showed that contaminants are migrating in an easterly direction in line with the prevailing wind direction and we were able to identify areas in which the radiological risk is likely high. The mean effective dose rate was 2.51 ± 0.98 mSv y−1 which was equivalent to the levels obtained in previous works.

Dosimetry, biodistribution, and safety of flurpiridaz F 18 in healthy subjects undergoing rest and exercise or pharmacological stress PET myocardial perfusion imaging

The objectives of this study were to evaluate radiation dosimetry, biodistribution, human safety, and tolerability of 18F-labeled flurpiridaz (Flurpiridaz) in normal subjects undergoing rest and separate-day exercise or adenosine pharmacological stress PET imaging. Methods12 normal subjects were injected with 58.5 to 121 MBq (1.58 to 3.27 mCi) of Flurpiridaz intravenously at rest on Day 1 and 57 to 171 MBq (1.54 to 4.61 mCi) during stress on Day 2. Sequential whole-body imaging was performed for 5 hours. Blood samples were collected for up to 8 hours. ResultsThe heart wall received the largest mean absorbed dose with both exercise and adenosine stresses. The mean effective dose was 0.054 rem/mCi (0.015 mSv/MBq) with exercise and 0.069 rem/mCi (0.019 mSv/MBq) with adenosine pharmacological stress. The maximum dose that may be administered without exceeding 1 rem (10 mSv) effective dose was 19 mCi (685 MBq) for exercise and 15 mCi (539 MBq) for adenosine pharmacological stress. There were no drug-related adverse events, and the tracer was well tolerated in all subjects. ConclusionBased on radiation dosimetry, biodistribution, and safety observations, 18F-labeled flurpiridaz is found suitable for clinical PET myocardial perfusion imaging in conjunction with either exercise or pharmacological stress testing.