Radiation Dose Levels Research Articles

Terrestrial gamma radiation dose (TGRD) levels in northern zone of Bauchi, Nigeria: mapping and statistical relationship between gamma dose rates and geological formations

This present study aims to obtain baseline data of environmental terrestrial radiation and to assess the corresponding health risk in the ambient environment in Bauchi north. The Terrestrial gamma radiation dose rates (TGRD) of study area were measured on-site using a portable Radiation alert milli roentgen (mR) survey meter, with a total of 280 measured points which covered all geological formations of the study area. The TGRD ranged from 60.90 nGyh-1 to 313.20 nGyh-1 with a mean value of 165.48 nGyh-1, which is about two times higher than the world average value of 59 nGyh-1 . Geological formation (Granites) was found to have the highest mean TGRD value of 194.88 nGyh-1. Likewise, Geological formation (Quartenary sedimentary) appeared to have the lowest mean TGRD value of 151.82 nGyh-1. The map for the distribution and exposure rate due to TGRD for the study area was also plotted using Golden surfer 12 software. One-way ANOVA was used to investigate the variation of the significant difference between the geological formations with TGRD, which shows the influence of geological formation on the measured TGRD values of the study area. Measured data could further be used to evaluate the public radiation exposure and in formulating safety standards and radiological guidelines.

Optimized radiological alert thresholds based on device-dosimetric information to predict peak skin dose between 2 and 4Gy during vascular fluoroscopically guided intervention.

To provide radiologists and physicists with methodological tools to improve patient management after vascular fluoroscopically guided intervention (FGI) by providing optimized thresholds (OT) values that could be used as a surrogate to the thresholds classically proposed by the National Council on Radiation Protection (NCRP) or could be useful to adapt their own substantial radiation dose levels (SRDL) values. PSD of 2000-4000mGy after FGI were calculated for 258 patients with dedicated software. Overall, the kerma and KAP 3D-ROC curves were used to assess the sensitivity (SEN) and specificity (SPE) of NCRP thresholds and OT for each PSD. Kiviat diagram and density curves were plotted for the best SEN/SPE pair of 3D-ROC curves and compared to the NCRP thresholds. OT for both kerma and KAP generating the best SEN/SPE couple for PSD of 2000-4000mGy were obtained. The SEN/SPE couple of each OT was always better than that obtained using NCRP ones. The best OT among all those calculated providing the highest SEN/SPE values for kerma (3020.5mGy) and KAP (741.02Gy.cm2) were obtained when PSD was equal to 3300mGy. We have calculated OT in terms of kerma and KAP based on 3D-ROC curves analysis and peak skin dose calculations that can be obtained to better predict high skin dose. The use of OT that predicted PSD greater than 3000mGy is likely to improve patient follow-up. The methodology developed in this work could be adapted to other institutions in order to better define their own SRDL. • Optimized dose thresholds in terms of kerma and KAP based on 3D-ROC curves analysis and peak skin dose calculations between 2000 and 4000mGy can be obtained to better predict high skin dose. • Patients receiving a peak skin dose between 2000 and 4000mGy have their follow-up enhanced by using the optimized thresholds instead of the NCRP thresholds. • The best-optimized thresholds, corresponding to 3020.5mGy and 741.02Gy.cm2 for kerma and KAP respectively can be used instead of NRCP ones to trigger patient follow-up after fluoroscopically guided vascular interventions.

Comparison of OSL and TL dosimetry systems against IEC and ICRP standards

Personal and environmental radiation monitoring services are widely used through luminescent techniques. In this paper, we practiced performance testing on thermoluminescent and optically stimulated luminescent dosimeters by assessing their homogeneity, linearity, energy, and angular dependence tests. The IEC and ICRP requirements were used to compare the performance response of dosimeters. Based on the experimental results, we realized that both detectors comply with the international criteria. The homogeneity percentage was 8.9% and 13.7% for TL and OSL detectors, respectively. The percentage deviation of the linearity test does not exceed 10% for both dosimeters except for the TL dosimeters at low irradiation dose. For the angular dependence, deviations were less than 2% for TLDs and 5% for OSLDs. These detectors display mean values of the relative energy response of −15.29% and −6.51% for OSL and TL detectors. Generally, TL materials manifested low sensitivity to radiation dose levels. On the other hand, the OSLDs demonstrated a more pronounced under-response to energy beam qualities than TLDs. Regarding COV tests, TL and OSL dosimeters have passed the c2 test.

Relationship of radiation-induced genomic instability and antioxidant production in the chamomile plant

Purpose To verify the hypothesis about the preservation of signs of radiation-induced genomic instability at the flowering stage of the chamomile plant after pre-sowing seed irradiation, the interaction of dose-dependent changes in the level of DNA damage and stimulation of antioxidant production. Materials and methods The study was carried out on two genotypes of chamomile, Perlyna Lisostepu variety and its mutant, using pre-sowing seed radiation exposure at dose levels 5–15 Gy. Studies of the rearrangement of the primary DNA structure of under different doses were studied on plant tissues at the flowering stage using – ISSR and RAPD DNA markers. Dose-dependent changes relative to the control of the amplicons’ spectra were analyzed using the Jacquard similarity index. Antioxidants such as flavonoids and phenols were isolated from pharmaceutical raw materials (inflorescences) using traditional methods. Results Preservation of multiple DNA damages at the stage of plant flowering under pre-sowing seed irradiation at low doses was confirmed. It was found that the largest rearrangements of the primary DNA structure of both genotypes, manifested in reduced similarity with the control spectra of amplicons, were observed under irradiation dose levels 5–10 Gy. There was a tendency to approach this indicator to the control under 15 Gy dose, which means increasing efficiency of the reparative processes. The relationship between the polymorphism of the primary structure of DNA by ISSR-RAPD-markers in different genotypes and the nature of its rearrangement under radiation exposure was shown. Dose dependences of changes in the specific content of antioxidants were non-monotonic with a maximum at 5–10 Gy. Conclusions Comparison of dose dependences of changes in the coefficient of similarity of the spectrum of amplicons between irradiated and control variants with nonmonotonic dose curves in the specific content of antioxidants allowed to suggest that there was the antioxidant protection stimulation under the doses corresponding to low efficiency of repair processes. The decrease in the specific content of antioxidants followed the restoration of the genetic material normal state. The interpretation of the identified phenomenon has been based on both known connection between the effects of genomic instability and the increasing yield of the reactive oxygen species and general principles of antioxidant protection.

Utilization of three-layers heterogeneous mammographic phantom through MCNPX code for breast and chest radiation dose levels at different diagnostic X-ray energies: A Monte Carlo simulation study.

We report the breast and chest radiation dose assessment for mammographic examinations using a three-layer heterogeneous breast phantom through the MCNPX Monte Carlo code. A three-layer heterogeneous phantom along with compression plates and X-ray source are modeled. The validation of the simulation code is obtained using the data of AAPM TG-195 report. Deposited energy amount as a function of increasing source energy is calculated over a wide energy range. The behavioral changes in X-ray absorption as well as transmission are examined using the F6 Tally Mesh extension of MCNPX code. Moreover, deposited energy amount is calculated for modeled body phantom in the same energy range. The diverse distribution of glands has a significant impact on the quantity of energy received by the various breast layers. In layers with a low glandular ratio, low-energy primary X-ray penetrability is highest. In response to an increase in energy, the absorption in layers with a low glandular ratio decreased. This results in the X-rays releasing their energy in the bottom layers. Additionally, the increase in energy increases the quantity of energy absorbed by the tissues around the breast.

Physiological and biochemical markers of gamma irradiated white radish (Raphanus sativus)

Purpose A field experiment was performed to investigate the impact of low-dose gamma rays on growth parameters and bioactive compounds of white radish. Materials and methods White radish seeds were irradiated by gamma rays dose levels (10, 20, 40 and 80 Gy) beside control. Physiological and biochemical markers were done to follow the effect of gamma rays on white radish. Results The results revealed that gamma rays increased growth parameters with increasing irradiation to a dose of 40 Gy. The maximum increments were found at 14.64 (cm), 48.30 (cm), 20.84 (cm) and 5.51 (cm) for leaves number, leaves length, roots length and roots diameter, respectively, with a dose of 40 Gy. By increasing the irradiation dose to 80 Gy, the results showed reduction in all parameters studied. Ascorbic acid gave the maximum increase with the dose of 40 Gy, while phenols, flavonoids, antioxidant activity, peroxidase, and polyphenol oxidase showed the highest increase with the dose 80 of Gy in radish leaves. Similar trend was observed for the radish roots. Furthermore, the protein and isoenzyme profiles of peroxidase and polyphenol oxidase changed and induced alteration by different irradiation dose levels. Conclusion Gamma rays can be a useful tool for increasing the growth and biochemical content of white radish plants and perhaps other food crops.

CDMAM in digital mammography: contrast threshold measurements, achievable values and relation with dose

The main goal of this study is to characterise threshold contrast values and average glandular dose (AGD) in mammography examinations, as well as their relationship with acceptable (minimum quality values) and achievable (desirable quality values) values from the fourth edition of the EUREF protocol. Therefore, data from 84 mammography units from six different manufacturers comprising 15 different models were gathered across Portugal during 2020 and 2021. The contrast measurements were obtained with a CDMAM 4.0 phantom. Within the tested units, six failed to comply with the acceptable EUREF values for threshold contrast and 5% achieved all levels of desirable contrast. Only 3% of the units presented values above an achievable AGD level of 2.4 mGy for an equivalent breast thickness of 60 mm. As these acceptable and achievable values are used as a guideline for the setup of dose and image quality of mammography units, the obtained results demonstrate that clinical images are being produced with an AGD much lower than the achievable dose values. As a result, contrast threshold values are close to the minimum quality values, which could result in images with less diagnostic data, compromising the justification of x-ray exams. Results proved that there is a possibility for an increase in AGD to give achievable image standards. Higher levels of radiation dose correlated with better image quality, and consequently higher diagnostic confidence could be consistent with the optimisation principle for radiation protection.

Monitoring cone-beam CT radiation dose levels in a University Hospital.

To present patient dose levels for different CBCT scanners, acquired by a dose monitoring tool in a University Hospital, as a function of field of view (FOV), operation mode, and patient age. An integrated dose monitoring tool was used to collect radiation exposure data [type of CBCT unit, dose-area product (DAP), FOV size, and operation mode] and patient demographic information (age, referral department) performed on a 3D Accuitomo 170 and a Newtom VGI EVO unit. Effective dose conversion factors were calculated and implemented into the dose monitoring system. For each CBCT unit, the frequency of examinations, clinical indications, and effective dose levels were obtained for different age and FOV groups, and operation modes. A total of 5163 CBCT examinations were analyzed. Surgical planning and follow-up were the most frequent clinical indications. For the standard operation mode, effective doses ranged from 35.1 to 300 µSv and 9.26-117 µSv using 3D Accuitomo 170 and Newtom VGI EVO, respectively. In general, effective doses decreased with increasing age and FOV size reduction. Effective dose levels varied notably between systems and operation modes.Operation mode selection and FOV size were indication-oriented, with larger FOV sizes election serving surgical planning and follow-up. Seeing the influence of FOV size on effective dose levels, manufacturers could be advised to move toward patient-specific collimation and dynamic FOV selection. Systematically monitoring patient doses could be recommended for steering future CBCT optimization.

Awareness of Radiation Protection and Common Radiation Dose Levels Among Healthcare Workers.

Access to ionizing radiation has become widely available for diagnosis and treatment. The increased use of ionizing radiation has been associated with radiation exposure hazards for patients and radiation workers. Raising the level of radiation protection awareness is important to maintain the safety of healthcare settings. Online questionnaires were distributed to 755 healthcare workers and students at King Abdulaziz Medical City and King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia. The questionnaire consisted of 14 multiple-choice questions divided into two sections (questions related to radiation protection and common radiologic examination doses). In total, 443 participants completed the questionnaire, including 142 (32%) medical students, 107 (24%) radiology technologists, 105 (24%) radiography students, and 89 (20%) physicians. Of the participants, 245 (55%) were men. A total of 74 (84%) physicians and 51 (47%) radiology technologists had more than 5 years of experience. Eleven (12%) physicians and 44 (41%) radiology technologists had 1-4 years of experience, whereas the rest had less than 1 year of experience. Only 16% of participants attended training courses on a regular basis. However, 15% of the participants thought that they had excellent knowledge of radiation protection, whereas 18% admitted that they did not have sufficient knowledge. Sixty-two percent of the questions related to radiation protection awareness were answered correctly. Forty-five percent of the participants correctly answered questions related to doses from common radiologic examinations. Only 23% and 16% of participants were aware of the noncontrast chest CT and lumbar x-ray doses, respectively. Moreover, 35% and 24% of participants did not know that pelvic MRI and abdominal ultrasound do not contribute any radiation dose, respectively. The results showed a knowledge gap regarding radiation protection and dose levels; therefore, periodic refresher courses are recommended for healthcare workers in order to increase the level of awareness.

Evaluation occupationally radiation exposure during diagnostic imaging examinations

Occupational radiation exposure can occur due to various human activities, including the use of radiation in medicine. Occupationally exposed personnel surpassing 7.4 millions, and respresent the biggest single group of employees who are exposed to artificial radiation sources at work. This study compares the occupational radiation dose levels for 145 workers in four different hospitals located in the Aseer region in Saudi Arabia. The occupational exposure was quantified using thermoluminescence dosimeters (TLD-100). The levels of annual occupational exposures in targeted hospitals were calculated and compared with the levels of the international atomic energy agency (IAEA) Safety Standards. An average yearly cumulative dose for the two consecutive years. The average, highest and lowest resulted occupational doses under examination in this work is 1.42, 3.9 mSv and 0.72 for workers in various diagnostic radiology procedures. The resulted annual effective dose were within the IAEA approved yearly dose limit for occupational exposure of workers over 18, which is 20 mSv. Staff should be monitored on a regular basis, according to current practice, because their annual exposure may surpass 15% of the annual effective doses.

Application of metal artifact reduction algorithm in reducing metal artifacts in post-surgery pediatric low radiation dose spine computed tomography (CT) images.

The commonly used methods for removing metal-induced beam hardening artifacts often rely on the use of high energy photons with either high tube voltage or high energy virtual monoenergetic images in dual-energy computed tomography (CT), the radiation dose was usually relatively high in order to generate adequate signals. This retrospective study is designed to evaluate the application of a metal artifact reduction (MAR) algorithm in reducing pedicle screw metal-caused beam hardening artifacts in post-surgery pediatric low radiation dose spine CT images. Seventy-seven children (3-15 years) who had undergone a low dose CT with 140 or 100 kV were enrolled. The radiation dose was 1.40 mGy for the 3-8 years old and 2.61 mGy for 9-15 years old children. There were 116 pedicle screws evaluated. The raw data were reconstructed with adaptive statistical iterative reconstruction-V (ASIR-V) at 50% strength, ASIR-V with MAR (AV-MAR), deep learning image reconstruction (DLIR) at high strength and DLIR with MAR (DL-MAR). The image quality concerning pedicle screws was evaluated objectively in terms of the length of beam-hardening artifact (LHA) and artifact index (AI), and subjectively using a 4-point scale (4 points: best, 3 points: acceptable). Both AV-MAR and DL-MAR significantly reduced metal-induced beam hardening artifacts with smaller LHA (15.76±10.12 mm, a reduction of 57.24% and 15.66±10.49 mm, a reduction of 57.40%, respectively), and AI value (62.50±33.51, a reduction of 64.65% and 61.03±32.61, a reduction of 65.01%, respectively) compared to ASIR-V and DLIR (all P<0.01), The subjective image quality scores concerning the screws were 3.37±0.49 and 3.47±0.50 with AV-MAR and DL-MAR, respectively, higher than the respective value of 1.73±0.44 and 1.76±0.43 without MAR (all P<0.01). MAR significantly reduces the low-density artifacts caused by metal screws in post-surgery pediatric low-dose spine CT images, across different tube voltages, radiation dose levels and reconstruction algorithms. Combining DL-MAR further improves the overall image quality under low radiation dose conditions.

INSTITU MEASUREMENT OF GAMMA RADIATION DOSE LEVEL OF SCRAP METAL MARKETS IN JOS METROPOLIS- PLATEAU STATE, NIGERIA

In this research work, a survey of gamma radiation dose level in scrap metals from scrap metal markets in Jos metropolis was carried out using the gamma scout radiation detector. Measurement were taken from eleven randomly identified scrap metals market in Jos. Results from this study show that the mean background radiation was 0.213 µSv/hr with a maximum and minimum values of 0.299µSv/hr and 0.165 µSv/hr respectively. The maximum background_ADR(Background Annual Dose Rate) was 47.656µSv/yr and was observed in YTM and GCFGR markets which were mixed scraps and automobile scrap metals in nature. These values are higher than standard background radiation of 0.133µSv/hr and are below the ICRP maximum permissible limit of 0.57 µSv/hr. The values of the measured annual radiation dose rate for all the scrap markets[Gamma radiation Annual Dose Rate (A_ADR), Beta Annual Dose Rate (B_ADR), Alpha radiation Annual Dose Rate (C_ADR)] were lower than the ICRP recommended limit of 1000 µSv/yr (1 mSv/yr) for the public and 20000µSv/yr for occupationally exposed work personnel. The studied areas are confirmed to be within the permissible limit and so may not pose any significant radiological health effects or hazards on the general public and the workers. These findings suggest regular assessment should be carried out at these areas to ensure that exposures are kept as low as reasonably achievable and within the tolerable limit of exposures.

Clinical, immunological and genetic research on the participants in mitigating the consequences of the Chernobyl nuclear accident

Introduction. The paper presents the results of research on the influence of IR sources on the health of professionally and accidentally exposed personnel. Particular emphasis is placed on: identifying the relationships between the level of radiation dose and the development of oncological diseases; use of contemporary biological dosimetry methods for retrospective analysis of irradiation doses; the impact of parental irradiation on the health of the offspring; the structure of morbidity, including oncological diseases in patients exposed to IR sources.&#x0D; Material and methods. The study material was used by subjects professionally and accidentally exposed to IR sources: medical staff and PMCCNA born in the Republic of Moldova, Ukraine and the Russian Federation, as well as their descendants, victims of the accident at the Fukushima Daiichi nuclear power plant (Japan) and residents of the region. Chelyabinsk. Clinical, immunological and cytogenetic methods were used.&#x0D; Results. A wide range of mental pathologies was observed at PMCCNA, at the victims of the accident at the Fukushima Daiichi nuclear power plant, etc. The structure of immune deficiency syndromes was dominated by allergic and autoimmune syndromes. Based on the analysis of stable chromosomal aberrations, exposure doses were established.&#x0D; Conclusions. In the absence of dose information received by staff professionally/accidentally exposed to IR sources, assessment of stable chromosomal aberrations makes it possible to reconstruct the radiation dose for PMCCNA exposed to low doses of IR.

A new approach to dose reference levels in pediatric CT: Age and size-specific dose estimation

BackgroundAlthough paediatrics' are more radio-sensitivity than adults, the number of requested paediatric CT examinations is increasing globally. Significant efforts have been focused on achieving the lowest possible radiation dose for paediatric patients, particularly adjusting for size differences. This study aims to establish Diagnostic Reference Levels (DRLs) for paediatric patients based on size-specific dose estimates (SSDE). MethodIn this retrospective national study, CT scans for brain, chest, abdominopelvic, and chest, abdomen, and pelvis (CAP) were collected from four hospitals in Jordan undergoing paediatric CT scans. A total of 1818 cases were randomly selected in four age categories (<1 year, 1–4 years, 5–10 years, 11–18 years). The SSDE values were determined by multiplying the volume CT dose index (CTDIvol) with the conversion factor extracted from the American Association of Physicists in Medicine Report 204. ResultsVariations exist between the DRLs between the different hospitals, age groups, and variations in protocols with different types of CT scanners. The DRL values (CTDIvol, dose-length product (DLP) and SSDE) for the four age categories were as follows; <1 year: brain (47.88 mGy, 741.67 mGy cm and 58.40 mGy), chest (5.65 mGy, 124 mGy cm and 13.91 mGy), abdominopelvic (12.65 mGy, 321.5 mGy cm and 28.72 mGy) and CAP (16.12 mGy, 507.72 mGy cm and 38.04 mGy). 1–4 years, brain (54.79 mGy, 979.12 mGy cm and 55.88 mGy), chest (7.37 mGy, 220.85 mGy cm and 14.68 mGy), abdominopelvic (16.16 mGy, 424.72 mGy cm and 32.68 mGy) and CAP (16.13 mGy, 742.1 mGy cm and 33.54 mGy). 5–10 years: brain (65.03 mGy, 1129.94 mGy cm and 55.92 mGy), chest (12.57 mGy, 383.9 mGy cm and 22.45 mGy), abdominopelvic (12.34 mGy, 450.75 mGy cm and 22.23 mGy) and CAP (13.46 mGy, 748.85 mGy cm and 25.69 mGy). 11–18 years, brain (60.7 mGy, 1207.9 mGy cm and 41.81 mGy), chest examination (12.94 mGy, 496.2 mGy cm and 20.49 mGy), abdominopelvic (16.13 mGy, 803.07 mGy cm and 23.06 mGy) and CAP (16.13 mGy, 1101.5 mGy cm and 23.85 mGy). ConclusionThere were increases in CTDIvol, DLP, and SSDE with ascending age groups. SSDE and age are closely matched to delivered radiation in paediatric CT; however, radiation dose levels remain high in Jordan. This work highlights the need for caution when administering radiation in the paediatric population.

ASSESSMENT OF INDOOR AND OUTDOOR RADIATION DOSE LEVELS IN DELTA STATE POLYTECHNIC, OGWASHI-UKU, DELTA STATE, NIGERIA

This study assessed the indoor and outdoor radiation dose levels of twelve (12) laboratories of Delta State Polytechnic, Ogwashi-Uku using a handheld inspector survey meter and estimation revealed that the average BIR, average annual equivalent dose rate (EDR), average annual absorbed dose rate (ADR), average annual effective dose equivalent (AEDE), average excess lifetime cancer risk (ELCR) is 0.0116 mR/hr, 0.9733 mSv/yr, 100.69 nGy/hr, 0.4940 mSv/yr and 1.755. Dose to organs showed that the testes received the highest dose, while the liver received the lowest dose indoors and outdoors respectively. In general, indoor and outdoor BIR, ED, AD, and AEDE values ​​are less than the recommended limit of unity (1 mSv/yr) for public exposure (ICRP). ELCR for indoor and outdoor is above the world permissible limit of 0.29×10-3. The calculated ELCR in the study area is 1:29719 (about 33 in 1 million) indoors and 1:115735 (9 in 1 million) outdoors. Although the average value for ELCR in this study is high further analysis and studies need to be carried out to ascertain the risk of staff and students to cancer.

Evaluation of Diagnostic Accuracy of Abdominal Ct Scans by Assessment of Image Quality and Confidence

The study's objective is to assess the diagnostic accuracy and image quality of the abdomen CT scan by the recommendations of the International Commission on Radiological Protection. As a result, research that can be quantified and measured is done on a representative sample. The CTDIvol data was gathered over three months at the Al Makkased Islamic Charitable Society Hospital in Jerusalem from 123 CT adult belly exams. The study's findings suggest that, in comparison to many other hospitals throughout the world, Al-Makkased hospitals are using the belly examination more frequently. The samples were contrasted with the ICRP's global reference value. Two radiologists were supplied samples with low CTDIvol levels to assess the picture quality and confidence. The study report It was discovered that whereas 39% of the low CTDIvol samples did not affect the picture quality, 61% of the remaining samples did. The first radiologist reported a picture quality of 77% and a certainty of 91%; the second reported a picture quality of 79% and a certainty of 90%. The study discovered that the CT belly examination's CTDIvol was higher than the ICRP's global reference value, that 57 out of 123 samples had low CTDIvol, and that their proportion was 46%. This analysis does not include Japan. The overall picture quality was judged to be fair, while diagnostic certainty was found to be outstanding.&#x0D; Originality/value: Findings highlight discrepancies in radiation dose levels and underscore the importance of balancing dose reduction with diagnostic efficacy, contributing to improved imaging practices and patient safety.

Oncology-specific radiation dose and image noise reference levels in adult abdominal-pelvic CT

ObjectivesTo provide our oncology-specific adult abdominal-pelvic CT reference levels for image noise and radiation dose from a high-volume, oncologic, tertiary referral center. MethodsThe portal venous phase abdomen-pelvis acquisition was assessed for image noise and radiation dose in 13,320 contrast-enhanced CT examinations. Patient size (effective diameter) and radiation dose (CTDIvol) were recorded using a commercial software system, and image noise (Global Noise metric) was quantified using a custom processing system. The reference level and range for dose and noise were calculated for the full dataset, and for examinations grouped by CT scanner model. Dose and noise reference levels were also calculated for exams grouped by five different patient size categories. ResultsThe noise reference level was 11.25 HU with a reference range of 10.25–12.25 HU. The dose reference level at a median effective diameter of 30.7 cm was 26.7 mGy with a reference range of 19.6–37.0 mGy. Dose increased with patient size; however, image noise remained approximately constant within the noise reference range. The doses were 2.1–2.5 times than the doses in the ACR DIR registry for corresponding patient sizes. The image noise was 0.63–0.75 times the previously published reference level in abdominal-pelvic CT examinations. ConclusionsOur oncology-specific abdominal-pelvic CT dose reference levels are higher than in the ACR dose index registry and our oncology-specific image noise reference levels are lower than previously proposed image noise reference levels. Advances in knowledgeThis study reports reference image noise and radiation dose levels appropriate for the indication of abdomen-pelvis CT examination for cancer diagnosis and staging. The difference in these reference levels from non-oncology-specific CT examinations highlight a need for indication-specific, dose index and image quality reference registries.

Is it possible to use low-dose deep learning reconstruction for the detection of liver metastases on CT routinely?

To compare the image quality and hepatic metastasis detection of low-dose deep learning image reconstruction (DLIR) with full-dose filtered back projection (FBP)/iterative reconstruction (IR). A contrast-detail phantom consisting of low-contrast objects was scanned at five CT dose index levels (10, 6, 3, 2, and 1 mGy). A total of 154 participants with 305 hepatic lesions who underwent abdominal CT were enrolled in a prospective non-inferiority trial with a three-arm design based on phantom results. Data sets with full dosage (13.6 mGy) and low dosages (9.5, 6.8, or 4.1 mGy) were acquired from two consecutive portal venous acquisitions, respectively. All images were reconstructed with FBP (reference), IR (control), and DLIR (test). Eleven readers evaluated phantom data sets for object detectability using a two-alternative forced-choice approach. Non-inferiority analyses were performed to interpret the differences in image quality and metastasis detection of low-dose DLIR relative to full-dose FBP/IR. The phantom experiment showed the dose reduction potential from DLIR was up to 57% based on the reference FBP dose index. Radiation decreases of 30% and 50% resulted in non-inferior image quality and hepatic metastasis detection with DLIR compared to full-dose FBP/IR. Radiation reduction of 70% by DLIR performed inferiorly in detecting small metastases (< 1 cm) compared to full-dose FBP (difference: -0.112; 95% confidence interval [CI]: -0.178 to 0.047) and full-dose IR (difference: -0.123; 95% CI: -0.182 to 0.053) (p < 0.001). DLIR enables a 50% dose reduction for detecting low-contrast hepatic metastases while maintaining comparable image quality to full-dose FBP and IR. • Non-inferiority study showed that deep learning image reconstruction (DLIR) can reduce the dose to oncological patients with low-contrast lesions without compromising the diagnostic information. • Radiation dose levels for DLIR can be reduced to 50% of full-dose FBP and IR for detecting low-contrast hepatic metastases, while maintaining comparable image quality. • The reduction of radiation by 70% by DLIR is clinically acceptable but insufficient for detecting small low-contrast hepatic metastases (< 1 cm).

Impact of flexible noise control (FNC) image processing parameters on portable chest radiography.

There is a lack of understanding in the performance of flexible noise control (FNC) processing, which is used in digital radiography on a scanner vendor and has four parameters each involving multiple options. The aim of this study was to investigate the impact of FNC on portable chest imaging. An anthropomorphic chest phantom was imaged using a clinical chest program with 85kV and five radiation dose levels at 40″ source-to-image distance with software-based scatter reduction method. All images were processed without and with FNC. Noise analysis was performed in two regions of interest (ROI) on subtracted noise-only images, and line profiles were generated through a lung-rib interface. In addition, noise power spectra (NPS) analysis was performed in solid water phantoms of 10 and 20cm thicknesses, using the same acquisition program and a range of dose levels. Last, feedback on retrospectively deidentified, reprocessed, and randomized clinical images from 20 portable chest exams was gathered from two thoracic radiologists. Noise reduction performances of FNC were demonstrated, with the level depending on specific FNC parameters, dose levels, ROI placement, and phantom sizes. Higher frequency textural patterns were revealed through the NPS analysis, which varied based on FNC parameters, dose levels, and phantom sizes. Overall, the vendor default parameter FGA0.5 yielded the highest noise reduction and textural artifacts. Radiologist feedback showed consistent preference of no FNC due to the presence of textural artifacts in the FNC-processed images. An algorithm improvement to avoid introducing artifacts would be desired.

The risk factors and the relationship between radiation dose and complications and prosthetic reconstruction failure in patients with post-mastectomy breast implant reconstruction: a retrospective cohort study

The risk factors for breast implant reconstruction complications and prosthetic reconstruction failure are currently inconclusive. Besides, there is a lack of studies regarding the relationship between radiation dose distribution and complications. This study explored the risk factors for breast implant reconstruction complications and analyzed the influence of radiation dose distribution on complications. Patients undergoing breast prosthesis reconstruction between January 2012 and June 2020 were retrospectively reviewed. Patient demographics, treatments, and perioperative factors were recorded, as well as complications and prosthetic reconstruction failures. Multivariable logistic regression models were used to explore the risk factors of reconstruction complications and prosthesis reconstruction failure. The radiation dose distribution was obtained by examining the dose-volume histogram and compared among patients with and without complications. Two hundred and sixteen patients (221 reconstructions) were not irradiated, whereas 59 (59 reconstructions) received radiotherapy (RT). The median follow-up period was 47.7 months. Multivariate regression analysis showed that RT [odds ratio (OR) =2.000; 95% confidence interval (CI): 1.065-3.754; P=0.031] and chemotherapy (OR =2.226; 95% CI: 1.032-4.799; P=0.041) were independent risk factors for overall reconstruction complications; and hypertension (HT) (OR =8.222; 95% CI: 1.056-64.034; P=0.044) or RT (OR =2.442; 95% CI: 1.009-5.908; P=0.048) were risk factors for prosthetic reconstruction failure. There was a statistically significant difference in the radiation dose distribution between patients with and those without complications. Patients with complications had a significantly higher mean dose of 5 or 10 cc around the maximum radiation dose in the planning target volume (PTV) (P=0.045 and P=0.034, respectively), irradiation volume with a dose of 107% of prescription dose (P=0.027), and proportion of irradiation volume with doses of 105% and 107% of prescription dose to the total PTV (P=0.019 and P=0.042, respectively). RT can increase implant reconstruction complications and prosthetic reconstruction failure, but remains an acceptable option in a multidisciplinary setting. In addition to RT, chemotherapy is a risk factor for overall complications of breast implant reconstruction. HT is a risk factor for prosthetic reconstruction failure, so the patient's blood pressure should be actively monitored and controlled during the perioperative period. The radiation dose level and the volume with high-dose radiation should be limited to reduce complications.