Radiation dose in paediatric computed tomography: risks and benefits

Radiation dose analysis of computed tomography coronary angiography in Children with Kawasaki disease

BACKGROUND

There is evolving role of computed tomography coronary angiography (CTCA) in non-invasive evaluation of coronary artery abnormalities in children with Kawasaki disease (KD). Despite this, there is lack of data on radiation dose in this group of children undergoing CTCA.

AIM

To audit the radiation dose of CTCA in children with KD.

METHODS

Study (December 2013-February 2018) was performed on dual source CT scanner using adaptive prospective electrocardiography-triggering. The dose length product (DLP in milligray-centimeters-mGy.cm) was recorded. Effective radiation dose (millisieverts-mSv) was calculated by applying appropriate age adjusted conversion factors as per recommendations of International Commission on Radiological Protection. Radiation dose was compared across the groups (0-1, 1-5, 5-10, and > 10 years).

RESULTS

Eighty-five children (71 boys, 14 girls) with KD underwent CTCA. The median age was 5 years (range, 2 mo-11 years). Median DLP and effective dose was 21 mGy.cm, interquartile ranges (IQR) = 15 (13, 28) and 0.83 mSv, IQR = 0.33 (0.68, 1.01) respectively. Mean DLP increased significantly across the age groups. Mean effective dose in infants (0.63 mSv) was significantly lower than the other age groups (1-5 years 0.85 mSv, 5-10 years 1.04 mSv, and > 10 years 1.38 mSv) (P < 0.05). There was no significant difference in the effective dose between the other groups of children. All the CTCA studies were of diagnostic quality. No child required a repeat examination.

CONCLUSION

CTCA is feasible with submillisievert radiation dose in most children with KD. Thus, CTCA has the potential to be an important adjunctive imaging modality in children with KD.

Assessment of Scattered Dose to the Eye in Dentistry: A Systematic Review

Cone-beam computed tomography (CBCT) is a tool for dental imaging of impactions, maxillofacial discrepancies, facial trauma, and tumors. In addition, It is used in treatment planning for dental implants, orthognathic surgery, and general maxillofacial surgery. There are no standardized methods for utilizing CBCT dosimetry, and there is no consensus among dental and medical physics health professionals regarding dental CBCT imaging procedures. The eyes and thyroid glands are radiosensitive organs that lie outside the primary beam but receive a significant amount of radiation due to scattered radiation. This study aimed to assess the dose to eye lens in patients imaged using CBCT. This review aims to evaluate the scattered doses to the eye from CBCT among adult patients seeking dental treatment. The search included published articles in the Web of Science, PubMed (MeSH and Web PubMed), Medline, and Google Scholar databases using the appropriate keywords from January 2010 to July 2022. The inclusion criteria were based on the method of dose measurement (phantom studies using Optically stimulated luminescence (OSL) and Thermoluminescent dosimeter (TLD), language, and type of protocol used. A literature search was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist and flow chart. Out of 653 articles identified, 5 met the inclusion criteria. The results show that the scattered radiation dose ranged between 0.103 mSv and 8.3 mSv. This variation exists due to the difference in the field of vision (FOV), phantom exposure, dosimeters used, degree of rotation in the protocol, and finally, the scanner used. The scattered dose to the eye from CBCT is higher than the background radiation, with huge variability in the range of the dose measured. Clear guidelines for utilizing CBCT should be implemented, and dose reference levels should be established for benchmarking and optimization in practice.

An Overview on the Alignment of Radiation Protection in Computed Tomography with Maqasid al-Shari'ah in the Context of al-Dharuriyat

The increasing utilisation of computed tomography (CT) in the medical field has raised a greater concern regarding the radiation-induced health effects as CT imposes high radiation risks on the exposed individual. Adherence to radiation protection measures in CT as endorsed by regulatory bodies; justification, optimisation and dose limit, is essential to minimise radiation risks. Islam values every human being and Maqasid al-Shari'ah helps to protect human beings through its sacred principles which aim to fulfil human beings' benefits (maslahah) and prevent mischief (mafsadah). Alignment of the concept of radiation protection in CT within the framework of al-Dharuriyat; protection of faith or religion (din), protection of life (nafs), protection of lineage (nasl), protection of intellect ('aql) and protection of property (mal) is essential. This strengthens the concept and practices of radiation protection in CT among radiology personnel, particularly Muslim radiographers. The alignment provides supplementary knowledge towards the integration of knowledge fields between Islamic worldview and radiation protection in medical imaging, particularly in CT. This paper is hoped to set a benchmark for future studies on the integration of knowledge between the Islamic worldview and radiation protection in medical imaging in terms of other classifications of Maqasid al-Shari'ah; al-Hajiyat and al-Tahsiniyat.

Deep Learning in MRI-guided Radiation Therapy: A Systematic Review

MRI-guided radiation therapy (MRgRT) offers a precise and adaptive approach to treatment planning. Deep learning applications which augment the capabilities of MRgRT are systematically reviewed. MRI-guided radiation therapy offers a precise, adaptive approach to treatment planning. Deep learning applications which augment the capabilities of MRgRT are systematically reviewed with emphasis placed on underlying methods. Studies are further categorized into the areas of segmentation, synthesis, radiomics, and real time MRI. Finally, clinical implications, current challenges, and future directions are discussed.

Estimation of radiation doses and lifetime attributable risk of radiation-induced cancer in the uterus and prostate from abdomen pelvis CT examinations

Computed tomography (CT) scans are one of the most common radiation imaging modalities, and CT scans are rising steadily worldwide. CT has the potential to enhance radiography practice, but it also has the risk of drastically increasing patient doses. One CT procedure for the abdomen pelvis (AP) area can expose a patient's prostate or uterus to a substantial radiation dose, leading to concerns about radiation-induced cancer. This study aimed to estimate organ doses of the uterus and prostate and evaluate the lifetime attributable risk (LAR) of cancer incidence and mortality resulting from AP CT examinations. This retrospective study included 665 patients, of which 380 (57%) were female, and 285 (43%) were male. Data were collected from the picture archiving and communication system for AP CT procedures and exposure parameter data. Organ doses for the uterus and prostate were calculated using National Cancer Institute CT (NCICT) software. Based on the risk models proposed by the BEIR VII report, the calculated organ doses were used to estimate the LAR of prostate and uterus cancer incidence and mortality due to radiation exposure from AP CT procedures. The mean effective dose resulting from AP CT for females and males was 5.76 ± 3.22 (range: 1.13-12.71 mSv) and 4.37 ± 1.66 mSv (range: 1.36-8.07 mSv), respectively. The mean organ dose to the uterus was 10.86 ± 6.09 mGy (range: 2.13-24.06 mGy). The mean organ dose to the prostate was 7.00 ± 2.66 mGy (range: 2.18-12.94 mGy). The LAR of uterus and prostate cancer incidence was 1.75 ± 1.19 cases and 2.24 ± 1.06 cases per 100,000 persons, respectively. The LAR of cancer mortality rates from uterus and prostate cancers were 0.36 ± 0.22 and 0.48 ± 0.18 cases per 100,000 persons, respectively. The LAR of prostate and uterus cancer occurrence and mortality from radiation doses with AP CT procedures was low but not trivial. Therefore, efforts should be made to lower patient doses while retaining image quality. Although the minimization of the patient's radiation dose must guide clinical practice, the estimated slight increase in risk could aid in easing fears regarding well-justified AP CT procedures.

Liver fat in adult survivors of severe acute malnutrition

The association between severe acute malnutrition (SAM) in early childhood and liver fat in adults is unknown. We hypothesized that exposure to SAM, especially severe wasting, is associated with fatty liver later in life. In this observational study, abdominal CT was used to quantify mean liver attenuation (MLA) and liver:spleen attenuation ratio (L/S). Birth weight (BW), serum lipids, insulin resistance (homeostatic model assessment), anthropometry and intrabdominal fat were collected. Mean differences between diagnostic groups were tested and hierarchical regression analysis determined the best predictors of liver fat. We studied 88 adult SAM survivors and 84 community participants (CPs); age 29.0 ± 8.4 years, BMI 23.5 ± 5.0 kg/m² (mean ± SDs). SAM survivors had less liver fat than CPs (using L/S) (p = 0.025). Severe wasting survivors (SWs) had lower BW (-0.51 kg; p = 0.02), were younger, thinner and had smaller waist circumference than oedematous malnutrition survivors (OMs). In the final regression model adjusting for age, sex, birth weight and SAM phenotype (i.e., oedematous malnutrition or severe wasting), SWs had more liver fat than OMs (using MLA) (B = 2.6 ± 1.3; p = 0.04) but similar liver fat using L/S (p = 0.07) and lower BW infants had less liver fat (MLA) (B = -1.8 ± 0.8; p = 0.03). Greater liver fat in SWs than OMs, despite having less body fat, supports our hypothesis of greater cardiometabolic risk in SWs. Other postnatal factors might influence greater liver fat in survivors of severe wasting, suggesting the need to monitor infants exposed to SAM beyond the acute episode.

Paediatric diagnostic reference levels in computed tomography: a systematic review

This study aims to review the existing literature on diagnostic reference levels (DRLs) in paediatric computed tomography (CT) procedures and the methodologies for establishing them. A comprehensive literature search was done in the popular databases such as PubMed and Google Scholar under the key words 'p(a)ediatric DRL', 'dose reference level', 'diagnostic reference level' and 'DRL'. Twenty-three articles originating from 15 countries were included. Differences were found in the methods used to establish paediatric CT DRLs across the world, including test subjects, reference phantom size, anatomical regions, modes of data collection and stratification techniques. The majority of the studies were based on retrospective patient surveys. The head, chest and abdomen were the common regions. The volume computed tomography dose index (CTDI_vol) and dose-length product (DLP) were the dosimetric quantities chosen in the majority of publications. However, the size-specific dose estimate was a growing trend in the DRL concept of CT. A 16 cm diameter phantom was used by most of the publications when defining DRLs for head, chest and abdomen. The majority of the DRLs were given based on patient age, and the common age categories for head, chest and abdomen regions were 0-1, 1-5, 5-10 and 10-15 years. The DRL ranges for the head region were 18-68 mGy (CTDI_vol) and 260-1608 mGy cm (DLP). For chest and abdomen regions the variations were 1.0-15.6 mGy, 10-496 mGy cm and 1.8-23 mGy, 65-807 mGy cm, respectively. All these DRLs were established for children aged 0-18 years. The wide range of DRL distributions in chest and abdomen regions can be attributed to the use of two different reference phantom sizes (16 and 32 cm), failure to follow a common methodology and inadequate dose optimisation actions. Therefore, an internationally accepted protocol should be followed when establishing DRLs. Moreover, these DRL variations suggest the importance of establish a national DRL for each country considering advanced techniques and dose reduction methodologies.

Diagnostic Reference Level of Radiation Dose and Image Quality among Paediatric CT Examinations in A Tertiary Hospital in Malaysia

Pediatrics are more vulnerable to radiation and are prone to dose compared to adults, requiring more attention to computed tomography (CT) optimization. Hence, diagnostic reference levels (DRLs) have been implemented as part of optimization process in order to monitor CT dose and diagnostic quality. The noise index has recently been endorsed to be included as a part of CT optimization in the DRLs report. In this study, we have therefore set local DRLs for pediatric CT examination with a noise index as an indicator of image quality. One thousand one hundred and ninety-two (1192) paediatric patients undergoing CT brain, CT thorax and CT chest-abdomen-pelvis (CAP) examinations were analyzed retrospectively and categorized into four age groups; group 1 (0-1 year), group 2 (1-5 years), group 3 (5-10 years) and group 4 (10-15 years). For each group, data such as the volume-weighted CT dose index (CTDIvol), dose-length product (DLP) and the effective dose (E) were calculated and DRLs for each age group set at 50th percentile were determined. Both CT dose and image noise values between age groups have differed significantly with p-value < 0.05. The highest CTDIvol and DLP values in all age groups with the lowest noise index value reported in the 10-15 age group were found in CT brain examination. In conclusion, there was a significant variation in doses and noise intensity among children of different ages, and the need to change specific parameters to fit the clinical requirement.

Quality Initiative to Reduce Cardiac CT Angiography Radiation Exposure in Patients with Congenital Heart Disease

Background

The use of cardiac computed tomography angiography (CCTA) as a complementary diagnostic modality to echocardiography in patients with congenital heart diseases (CHDs) is expanding in low- and middle-income countries. The adoption of As Low As Reasonably Achievable techniques is not widespread, resulting in significant unintended radiation exposure, especially in children. Simple quality improvement measures geared toward reducing radiation dose can have a impact on patient safety in resource-limited centers in low- and middle-income countries.

Objectives

To determine how a quality improvement initiative can reduce radiation exposure during CCTA in patients with CHD.

Methods

We designed a key driver -based quality initiative to reduce radiation dose during CCTA for CHD using protocol optimization, communication, and training and implementation as the drivers for intervention. Preintervention variables (radiation exposure, scanning protocols, and image quality) were collected from September 2012 to July 2016 and compared with variables in the postimplementation phase (February 2017 to July 2017). We compared quantitative and categorical variables using the chi-square test. Linear regression analysis was used to evaluate the effect of various factors on radiation dose.

Results

We documented a reduction in the effective dose in the postintervention versus preintervention phase (mean, 2.0 versus 21 mSv, P < 0.0001, respectively). Linear regression showed that the optimal organizational levels are associated with the same reduction in radiation. This finding shows that the time factor translates a combination of organizational and technical factors that contributed to the reduction in radiations.

Conclusions

Our project showed a reduction in CCTA-associated radiation exposure.

Pediatric Residents' and Medical Interns' Awareness about Pediatric Ionizing Radiation Dose from Computed Tomography and Its Associated Risks in Tertiary Hospital in Ethiopia

Background

The international literature on physicians' knowledge regarding radiation dosages and risks due to computed tomography showed a widespread underestimation of diagnostic radiation doses. Hence, the objective of this work is to assess the awareness of pediatric residents and medical interns about pediatric CT dose and possible risks.

Methods

A cross-sectional study was conducted on May/2016 among year I to year III pediatric residents and 2015/2016 year medical interns attaching Pediatrics Department during the study period in Tikur Anbessa Specialized Referral and Teaching Hospital. Data was collected by distributing standardized structured questionnaires. Finally, after the data was checked for clarity and completeness, it was analyzed by using SPSS software.

Result

While the majority (76.3%) of the residents and interns knew that children were more sensitive to radiation than adults, 93.7% did not know that there is currently no annual dose limit set for medical exposure of patients. The majority of the respondents (81.3%) know the risk of cancer from CT scan, but most (60%) of the respondents did not know that many imaging facilities still use adult doses for pediatric patients. Furthermore, 18.8% thought that magnetic resonance imaging involves ionizing radiation, and 8.9% of the physicians associated ultrasound examinations with ionizing radiation.

Conclusion

Within resident group, since the level of clinical experience did not affect the outcome, we recommend that formal education and training on awareness of radiation with special concern on pediatric population is mandatory especially for pediatric residents and pediatricians who are major caretakers of children.

CT radiation dose awareness among paediatricians

BACKGROUND

The radiation dose delivered from computed tomography (CT) scanning and the risks associated with ionising radiation are major concerns in paediatric imaging. Compared to adults, children have increased organ sensitivity and a longer expected lifetime in which cancer may develop. Therefore, it is important to investigate the awareness of paediatricians (referring physicians) regarding radiation doses and the associated risks.

METHODS

A multiple-choice survey was distributed among paediatricians in 8 hospitals in Riyadh, the capital of Saudi Arabia.

RESULTS

Among the 162 respondents, only 24 (15 %) were aware of the As Low As Reasonably Achievable (ALARA) principle. Approximately half (54 %) of the respondents believed that multi-slice CT delivered a low radiation dose, and 100 (62 %) of the respondents were not aware that radiation is considered carcinogenic by the Food and Drug Administration in the United States. Among the respondents, 110 (68 %) did not have any specific education regarding radiation during their training. There was an overall underestimation (83 %) of the CT radiation dose, and 70 % thought that magnetic resonance imaging (MRI) delivered some level of ionising radiation.

CONCLUSIONS

Among paediatricians in Saudi Arabian hospitals, there was a wide underestimation of the CT radiation dose and the associated risks for children. We should improve paediatricians' knowledge about radiation doses. Radiologists, paediatricians, radiation technologists and medical physicists should work together to optimise CT guidelines and protocols to reduce the radiation risks for children.

Assessment of Radiation doses to Paediatric Patients in Computed Tomography Procedures

Background

The use of pediatric CT that had recently emerged as a valuable imaging tool has increased rapidly with an annual growth estimated at about 10% per year. Worldwide, there is a remarkable increase in the number of CT examinations performed. The purposes of this study are to: (i) to measure the radiation dose and estimate the effective doses to pediatric patients during CT for chest, abdomen and brain.

Material/Methods

A total of 182 patients were investigated. CT scanners that participated in this study are helical CT scanners (64 slices, 16 slices and dual slices). Organ and surface dose to specific radiosensitive organs were estimated by using software from National Radiological Protection Board (NRPB).

Results

For all patients, the age was ranged between 1.12 month–10.0 years while the weight was ranged between 5.0 kg to 29.0 kg. The DLP was 320.58 mGy·cm, 79.93 mGy·cm, 66.63 mGy·cm for brain, abdomen and chest respectively. The effective dose was, 2.05, 1.8, 1.08 mSv for brain, abdomen and chest respectively.

Conclusions

The patient dose is independent of CT modality and depends on operator experience and CT protocol. The study has shown a great need for referring criteria, continuous training of staff in radiation protection concepts. Further studies are required in order to establish a reference level in Sudan.