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Size-specific dose estimate (SSDE), which can be calculated by measuring the effective diameter (D e) or water equivalent diameter (D w) of the patient, is one of the recent approaches for verifying the individual doses during computer tomography (CT) examinations. This work aimed to compare the D w estimated by the AutoWED tool and IndoseCT software and to investigate CT axial (ARH) and paediatric head (PH) protocols used in southern Saudi Arabia to calculate the dose received by paediatric patients using metrics of volume CT dose index (CTDIvol) and SSDE. The distribution between the ARH and PH protocols was 57.8 and 42.2%, respectively. There was no significant difference in D w values between the AutoWED tool and the IndoseCT program (0.13%). Including CT table or other objects during estimation of D w can lead to variation up to 11.4%. The impact of selecting IndoseCT options to identify the border of the patient may be part of the explanation for these variations. A strong linear relationship was obtained between D e and D w in paediatric head size (R 2 = 0.96). Using IndoseCT, for 0–1.5, 1.5–5 and 5.0–18 age groups (years), the D w was found to be 13.2, 15.3 and 16.8 cm, respectively. The SSDE for the PH protocol was substantially lower than that of the ARH protocol. As a result, education of the individuals engaging in paediatric CT examinations is necessary for dose optimization. [ABSTRACT FROM AUTHOR]

The present study compares three different multidetector CT (MDCT) scanners for routine brain imaging in terms of image quality and radiation doses. The volume CT dose index (CTDIvol), dose-length product (DLP), and effective dose (E) were calculated. Subjective image assessment was obtained based on a scale ranging from 1 (unacceptable) to 5 (optimum). All images scored 3.5 or over, with the 160-slice MDCT images being favoured. For the 4-, 16- and 160-slice MDCT scanners, the respective median values for CTDIvol were 57 mGy, 41 mGy, and 28 mGy; DLP values were 901 mGy.cm, 680 mGy.cm, and 551 mGy.cm; and effective doses were 2 mSv, 1.5 mSv, and 1 mSv, respectively. Compared to the 160-slice MDCT, the dose values for the 4- and 16-slice units were significantly greater. In practice, the CT modality used must be carefully selected to avoid elevated radiation doses and maintain image quality. [ABSTRACT FROM AUTHOR]

Computed tomography perfusion (CTP) is contrast-enhanced dynamic imaging of the brain utilized to assess the blood flow volume and transmit time to the brain's parenchyma. Stroke is the world's second greatest cause of mortality, accounting for 11% of all deaths, and a major cause of disability. Previous studies reported a high radiation dose per procedure with an eye lens equivalent dose (mGy) ranging from 81.0 mGy to 348.0 mGy. This study's objective is to evaluate patients exposure during CTP procedures. Materials and methods. Three hundred twenty patients with ischemic stroke underwent CTP were examined at King Fahad Medical City (KFMC). The imaging protocol consists of plain CT, CT angiography (CTA), CTP, Angiography. The volume CT Dose Index (CTDIvol, mGy) and dose length product (DLP, mGy.cm) were registered from the PACS system. The effective dose calculation (E, mSv) was extrapolated using computer software. For the CTP procedure, the mean and range of DLP (mGy.cm) for the complete procedure, CT brain, CTA, CTA digital subtraction angiography (DSA), and CTP were 1045 (105–3072), 843 (277–1530), 470.5 (210–1356), 238.8 (105–439), 2712(2012–3072) examinations, respectively. The mean and range of the effective dose (mSv) and CTDIvol (mGy) were 13.2 (10.6–17.1), 80.5 (6.11–256), in that order. The patients' doses showed wide variation due to the selection of multiple phases of acquisition and exposure factors. The dose is higher than most previous studies. Radiation dose optimization is recommended by establishing diagnostic reference level (DRL), proper CT machine setting, and increasing operators' awareness regarding radiation risks. • Multimodal computed tomography (CT) radiation doses were quantified for 72 patients. • Multimodal consists of noncontrast, angiography, digital subtraction angiography, and Perfusion CT procedure. • Multimodal CT brain procedure resulted in an effective dose of 6–15 mSv. • The use of the CTP- DSA procedure exposes the patients to unnecessary radiation. [ABSTRACT FROM AUTHOR]

The purposes of this study are to estimate patient's radiation doses and radiogenic risk in vascular lower limb computed tomography (CT). In total, 188 (109 (68%) males and 79 (42%) females) patients undergone vascular CT for the lower limbs at three radiology departments. Three CT scanners, 160, 128, and 64 slices CT, were used in this study. CT-Expo and ImPACT CT dose estimation software were used to extrapolate the effective dose. The overall average and range of volume CT dose index (CTDIvol (mGy) and dose length product (DLP) (mGy.cm) 7.3 (2.3–22.9), and 3000 (279.1–8374.4) the same order. The overall effective dose average value was 18 mSv per procedure. The proposed diagnostic reference level (DRL) values are 9 mGy (CTDIvol) and 2500 mGy cm (DLP) per vascular lower limb CT procedure. The risk of cancer from the peripheral CT angiography procedures ranges from 1 in 1000 to 1 in 3000 procedures. The cancer risk per procedure should be considered during the justification and image acquisition stages. • Peripheral CT angiography for lower extremities were performed using three CT machines. • CT dose per procedure (DLP (mGy.cm) is higher up to 10 times compared to previous. • Patients are being seen to be receiving unnecessary radiation doses during triphasic CT abdomen procedure. • A local diagnostic reference level was proposed was established for further dose reduction. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) has become a prominent source of medical exposures, conduct requiring measures that mitigate radio carcinogenic risk and deterministic tissue reaction effects. The objective of present study, conducted in Sudan, has been to evaluate patient radiogenic risk during vascular CT procedures. Study was made of 485 patients, the cohort comprising 218 males (45%) and 267 females (55%) of mean age ± 1 s.d. of 48.2 ± 17 years (ranging from 18.0 to 93.0 years). The investigation involved nine radiology departments, covering three different CT modalities (16, 64 and 128 slice). Patient organ and effective doses were estimated using established computer software (specifically, CT-Expo, ImPACT and that of the NRPB). The range of patient dose in terms of dose length product (DLP) (mGy.cm) and volume CT dose index (CTDI vol (mGy) were 3.2–28.51 mGy and 257.0–9263.5, respectively. The mean and range of effective dose were 25.5 ± 18 mSv and 4.0–138.9 mSv respectively. The wide range of doses indicates the likelihood that patients have been receiving avoidable radiation exposure, their being potential for mitigation of cancer incidence risk through further optimisation of procedures. On the basis of present study of vascular CT procedure doses, the mean risk of carcinogenesis has been estimated to be 1 in 1000 procedures. • Patients radiation doses were evaluated during vascular CT procedures for various CT modalities. • Effective dose were estimated using computer software. • The wide range of observed patient doses indicates patients to have been receiving avoidable radiation exposure. • The mean risk of carcinogenesis has been estimated to be 1 in 1000 procedures. [ABSTRACT FROM AUTHOR]

Renal diseases and urinary tract disorders are causing a global burden, with an estimated prevalence of around 13%. Contrast-enhanced computed tomography urography (CE-CTU) is a well-known diagnostic technique for urinary system diseases for initial diagnosis and, very often, for follow-up. CE-CTU procedure exposes patients to high doses of ionizing radiation; hence, justification and optimization of doses are necessary to maximize the benefits and minimize the patients' risks. This study aims to evaluate radiation doses to patients during CE-CTU procedures and estimate the subsequent radiogenic risk. The study included twenty-seven patients who underwent CE-CTU examination in two different hospitals (National Ribat Hospital (NRH) and National Security Fource Hospital (NSFH)), where 16-slice CT machines from different vendors are used. The variables and significance were analyzed using SPSS and Scheffe's statistical tool. Data collected included the age of patients (19–70 years), the radiation dose received by patients: dose length product (DLP, mGy.cm) and volume CT dose index (CTDIvol (mGy)), and tube current-time product (mAs). Patients' dose measurements per CE-CTU procedure given as (mean and range) was: DLP 3098 (647–5301) (mGy.cm) and CTDIvol 44.11 (15–136) (mGy). The results revealed statistically significant differences in DLP (mGy.cm), CTDIvol (mGy), and mAs, and this could be attributed to discrepancies in protocols, machines, and operators among the hospitals and within each hospital. Considering gender, the variables (age, tube current-time product (mAs), and CTDIvol) showed no statistically significant differences. The radiogenic risks from the CE-CTU procedure were ≈1 per 400. Comparison between the two hospitals showed that the variables varied significantly between the hospitals studied, but no significant differences were found based on gender. CE-CTU with contrast medium exposes patients to high doses. Therefore, proper dose optimization is crucial. • The radiation doses during IVU and the subsequent risks from exposure are studied. • The entrance-surface air kerma (ESAK) and effective dose were quantified. • Calculation of the overall cancer risk yielded 5.85 per million procedures. • The effective and cancer risk are around ten times lower during IVU procedures compared to CTU. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) is the leading source of the cumulative effective doses to the general populace from medicinal and artificial sources. With the increased use of CT examinations comes the concern regarding the health effects of unnecessary radiation exposure and the need to optimize the doses that patients receive. The current study evaluates the patients' doses during specific CT procedures and establishes institutional diagnostic reference levels (DRLs) for the frequent CT scans performed. 8156 CT scan examinations were performed during three years from 2015 to 2018 using a single CT scan machine at our institution. Data from the six most common examinations were analyzed. The volume CT dose index (CTDIvol (mGy)) and dose length product (DLP) distribution's median and 75th percentile values were computed. The results were descriptively compared with DRLs from different countries and regions. The six most common examinations constituted 5815 studies. We established our DRLs as the median value of CTDIvol (mGy)| and DLP (mGy × cm) as follows: CT of the brain: 35.0 mGy and 839 mGy × cm, respectively; chest with contrast: 4 mGy and 148 mGy-cm, respectively; chest without contrast: 5 mGy and 190 mGy-cm, respectively; abdomen and pelvis with contrast: 8 mGy and 636 mGy-cm, respectively; abdomen and pelvis without contrast 8 mGy and 568 mGy-cm, in that order; abdomen, pelvis, and kidneys: 11 mGy and 458 mGy × cm, respectively. Our values for brain and chest CTs were lower than the international DRLs, while those for abdominal imaging were higher. The established DRLs offer an opportunity for us to optimize the dose delivered to patients and compare them to the national benchmarks when they are issued. The study revealed that CT dose showed wide discrepancies for the same procedures at the department levels suggesting that the practice was neither optimized nor harmonized. Therefore, DRL should be reassessed after the operators' training and awareness to reduce the patients' dose and related radiogenic risk to its minimal value. • DRL was quantified for six standard CT examinations. • The study revealed that CT dose showed wide discrepancies for the same procedures. • The proposed DRLs are within the international values. • DRL should be reassessed after the technologists' training on imaging protocol optimization. [ABSTRACT FROM AUTHOR]

A significant source of ionizing radiation for medical use is computed tomography (CT). According to estimates, more than 84 million CT scans are carried out yearly in the US. Because the neck area contains several organs and tissues that are very sensitive to ionizing radiation, such as the thyroid gland, CT for the neck region is commonly done for a variety of clinical causes. This study's goal is to assess the patient doses to radiosensitive organs and effective doses received during the CT neck surgery in the pastAt Riyadh Care Hospital, a multislice CT (MSCT) system (Siemens Somatom Sensation, 64 slices/detector) was used to perform improved CT treatments on a total of 54 patients. Patient ages were 41.5–15.5 years old on average, with a wide variation (21–73). Using computer software based on Monte Carlo simulation, organ and effective dosages were assessed. The International Commission of Radiological Protection (ICRP) risk variables were used to calculate the patient's radiogenic risk for a particular organ. The patients' dose length product (DLP, mGy.cm) for CT neck examination were 993.3 ± 539.5 (267.3–2441.7). The mean and range of volume CT dose per slice (CTDIvol (mGy)) were 1.5 ± 3.9 (3.91–22.55). The overall effective dose (mSv) per procedure is ranged from 1.3 to 11.7 with a mean value 2.8 mSv. Patients' CT neck procedures have been repeated the procedure up to 7 times during the treatment course. The risk of malignancy is 1x10-6 CT procedure. The study showed that patients received wide discrepancies in patients' doses up to 9 times. Optimization of image acquisition protocol and scan length is necessary to reduce the unnecessary risk. • The effective and organ equivalent doses during neck CT procedure were studied. • Lens of the eye, salivary gland and thyroid gland received a high radiation dose. • The overall effective dose (mSv) per procedure is ranged from 1.3 to 11.7 • Patients' CT neck procedures have been repeated the procedure up to 7 times during the treatment course. [ABSTRACT FROM AUTHOR]

Image-guided radiation therapy (IGRT) adds an additional imaging radiation dose to existing levels of therapeutic radiation. The extra radiation dose received by organs from multiple conae beam computed tomography (CBCT) scans can increase the probability of the secondary cancer risk. In this study, an effort has been made to assess CBCT dose and image quality for standard pre-sets defined for different organs namely, the chest, pelvis, brain, head and neck, and abdomen. The second goal was to investigate whether the radiation dose could be reduced while still achieving high image quality. Image quality was evaluated on the CatPhan Model 503 (Phantom Lab, NY), while organ kV- CBCT doses were evaluated using an Unfors device (Fluke Biomedical) to provide representative measurements for clinical settings. Nominal CBCT projections with reduced exposure times were reconstructed in 3D using the Unfiltered and Filtered-back Projection algorithms. Patient organ dose (mGy) per procedure for brain, chest, pelvis, abdomen, and head and neck were 7.9, 35.3, 28.1, 58.3, and 0.77, respectively. The experimental analysis suggests that adequate image quality could be obtained while decreasing the number of radiographic projections. Reducing the number of the radiographic projections will reduce the scan time and therefore the imaging dose. The proposed method provides an opportunity to reduce the organ doses comparatively lower than the standard CT doses for head and body protocols. The study provides a framework for delivering low radiation doses to critical organs with no risk of long-term exposure. • This study has successfully quantified CBCT doses for some critical organs. • Image quality and radiation dose were evaluated during CBCT. • Adequate image quality could be obtained while decreasing the number of radiographic projections. • The study provides a framework for delivering low radiation doses to critical organs with no risk of long-term exposure. [ABSTRACT FROM AUTHOR]

Ionizing radiation exposure from medical applications is increasing annually worldwide. It was estimated that 325 million dental procedures were performed in the United States. Radiation exposure from dental radiography consists of intraoral, panoramic, and 3D imaging cone-beam computed tomography (CBCT) imaging. Recent studies reported an association between dental imaging procedures and increased cancer probability of brain and thyroid. Previous studies showed that some dental imaging practices exposed patients and staff to unnecessary radiation doses due to incorrect image acquisition and insufficient radiation protection measures. This study aims to (i) measure the occupational and patients doses during dental procedures and (ii) assess the current imaging techniques and radiation protection practices. Two hundred fourteen patients were evaluated for periapical, bitewing, cephalometric, occlusal, and panoramic procedures. Organ equivalent doses were quantified for the breast, eye lens, and thyroid gland during CBCT procedure. Occupational and ambient dose assessment were assessed using calibrated thermoluminescent dosimeters (TLD-100(LiF: Mg. Ti). Ambient doses were measure at different locations at the department using TLDs. Patients' radiation doses were quantified using kerma area product (PKA (mGy.cm) and the entrance surface air kerma (ESAK (mGy). Fixed tube voltage (65 kVp) and tube current-time product (7 mAs) were used. The overall mean, sd, and range of patients dose values during intraoral (mGy), panoramic and CBCT examinations were 4.6 ± 0.7 (1.4–7.1), 135 ± 45 (75.2–168.5), and 215 ± 165 (186–2115), respectively. The mean and range of the annual occupational doses (mSv) were 1.4 (0.6–3.7), which below the annual dose limits for radiation workers (20 mSv/y). The study showed that inadequate radiation protection for patients existed in terms of the use of the thyroid shield, the technologist's presence inside the room during radiation exposure. Patients' radiation doses were comparable with the international diagnostic reference level (DRL). Staff education and training in radiation protection aspects are highly recommended. • Radiation doses from intraoral, panoramic, and 3D imaging cone-beam computed tomography imaging were quantified. • Ambient and occupational doses were measure at different locations at the department using TLD. • The study showed that inadequate radiation protection for patients existed in terms of the use of the thyroid shield. • CBCT dose values, the patient radiation dose is around two times higher than for a panoramic imaging procedure. • The mean and range of the annual occupational doses (mSv) were below the annual dose limits for radiation workers. [ABSTRACT FROM AUTHOR]

During the last decade, the development of cone beam computed tomography (CBCT) has led to a large range of imaging methods. CBCT has advantages compared to other extraoral radiographic imaging, but its contribution to radiation dose in patients is a point of concern. This study aims to provide a full understanding and determination of absorbed dose and an estimation of effective dose to the thyroid, bone marrow, salivary glands and brain in patients during CBCT examinations and to estimate the radiogenic risk resulting from radiation exposure. In this study, a total of 157 pediatric and adult patients with different indications were investigated at the dental clinic. All procedures were performed using Planmeca ProMax 3D Max. Sensitive organ equivalent doses were estimated using PCXMC software. Organ equivalent doses were also estimated using PCXMC software. The fixed tube voltage was set to 90.0 kVp, the mean tube current was 12.7.0 mA (range: 8.0 to 14.0) and the mean exposure time was 12.5 ± 1.8 s (range: 12.0–16.0). The overall mean patient effective dose was 150.8 μSv (range: 22.4–210.0). Salivary gland equivalent dose was the highest of all the organs measured as no protective shield was used in these patients. Patient doses were slightly higher compared to those in previous studies. Poor patient protection conditions were noted. Staff training is a vital priority regardless of a low dose of CBCT compared to other imaging modalities. • Patients effective doses, eye lens and thyroid equivalent doses were estimated in cone beam CT. • CBCT examinations performed by operators with limited training in radiation protection. • Patient's doses is slightly higher compared to previous studies. • The radiogenic risk from CBCT procedure is low. [ABSTRACT FROM AUTHOR]