Cumulative Radiation Exposure Research Articles

Chest CT‐based automated vertebral fracture assessment using artificial intelligence and morphologic features

AbstractBackgroundSpinal degeneration and vertebral compression fractures are common among the elderly that adversely affect their mobility, quality of life, lung function, and mortality. Assessment of vertebral fractures in chronic obstructive pulmonary disease (COPD) is important due to the high prevalence of osteoporosis and associated vertebral fractures in COPD.PurposeWe present new automated methods for (1) segmentation and labelling of individual vertebrae in chest computed tomography (CT) images using deep learning (DL), multi‐parametric freeze‐and‐grow (FG) algorithm, and separation of apparently fused vertebrae using intensity autocorrelation and (2) vertebral deformity fracture detection using computed vertebral height features and parametric computational modelling of an established protocol outlined for trained human experts.MethodsA chest CT‐based automated method was developed for quantitative deformity fracture assessment following the protocol by Genant et al. The computational method was accomplished in the following steps: (1) computation of a voxel‐level vertebral body likelihood map from chest CT using a trained DL network; (2) delineation and labelling of individual vertebrae on the likelihood map using an iterative multi‐parametric FG algorithm; (3) separation of apparently fused vertebrae in CT using intensity autocorrelation; (4) computation of vertebral heights using contour analysis on the central anterior‐posterior (AP) plane of a vertebral body; (5) assessment of vertebral fracture status using ratio functions of vertebral heights and optimized thresholds. The method was applied to inspiratory or total lung capacity (TLC) chest scans from the multi‐site Genetic Epidemiology of COPD (COPDGene) (ClinicalTrials.gov: NCT00608764) study, and the performance was examined (n = 3231). One hundred and twenty scans randomly selected from this dataset were partitioned into training (n = 80) and validation (n = 40) datasets for the DL‐based vertebral body classifier. Also, generalizability of the method to low dose CT imaging (n = 236) was evaluated.ResultsThe vertebral segmentation module achieved a Dice score of .984 as compared to manual outlining results as reference (n = 100); the segmentation performance was consistent across images with the minimum and maximum of Dice scores among images being .980 and .989, respectively. The vertebral labelling module achieved 100% accuracy (n = 100). For low dose CT, the segmentation module produced image‐level minimum and maximum Dice scores of .995 and .999, respectively, as compared to standard dose CT as the reference; vertebral labelling at low dose CT was fully consistent with standard dose CT (n = 236). The fracture assessment method achieved overall accuracy, sensitivity, and specificity of 98.3%, 94.8%, and 98.5%, respectively, for 40,050 vertebrae from 3231 COPDGene participants. For generalizability experiments, fracture assessment from low dose CT was consistent with the reference standard dose CT results across all participants.ConclusionsOur CT‐based automated method for vertebral fracture assessment is accurate, and it offers a feasible alternative to manual expert reading, especially for large population‐based studies, where automation is important for high efficiency. Generalizability of the method to low dose CT imaging further extends the scope of application of the method, particularly since the usage of low dose CT imaging in large population‐based studies has increased to reduce cumulative radiation exposure.

The Prevalence of Cancer in Dutch Female Patients with Idiopathic Scoliosis Compared with the General Population.

Background and Objectives: Epidemiological studies have demonstrated the potential oncogenic effects of cumulative radiation exposure, particularly during childhood. One group experiencing repeated exposure to radiation at an early age for multiple years is patients treated for idiopathic scoliosis (IS). This study aimed to determine the relationship between childhood radiological exposure and adult cancer prevalence in children treated for IS. Materials and Methods: Data from 337 predominantly female patients treated at our hospital between January 1981 and January 1995 were gathered and compared to the Dutch national cancer rates. The standardized prevalence ratios for cancer in IS patients were compared with the cancer prevalence rates from the general Dutch population. Results: The overall cancer prevalence in women was 5.0%, with no significant difference compared to the general population (p = 0.425). The results of this study do not suggest that female patients treated for idiopathic scoliosis during childhood have an increased risk of cancer later in life. Conclusion: Despite being the largest recent study in its field, the modest participant number limits its ability to draw conclusions. However, the detailed data collected over a long observation period, alongside data from a period with comparable radiation rates, contributes to refining clinical practice and laying the groundwork for future systematic reviews.

Adjustment for duration of employment in occupational epidemiology

PurposeIn occupational epidemiology, the healthy worker survivor effect can manifest as a time-dependent confounder because healthier workers can accrue greater amounts of exposure over longer periods of employment. For example, in occupational studies of radiation exposure that focus on cumulative annualized radiation dose, workers can accrue greater amounts of cumulative radiation exposure over longer periods of employment, while workers with longer periods of employment can transition into jobs with a reduced potential for annualized radiation exposure. The extent to which confounding arising from the healthy worker survivor effect impacts radiation risk estimates is unknown. MethodsWe assessed the impact of the healthy worker survivor effect on estimates of radiation risk among nuclear workers in a Million Person Study cohort. In simulation studies, we contrasted the ability of marginal structural Cox models with inverse probability weighting and Cox proportional hazards models to account for time-dependent confounding arising from the healthy worker survivor effect. ResultsMarginal structural Cox models and Cox proportional hazards models with flexible functional forms for duration of employment provided reliable results. ConclusionsIt is crucial to flexibly adjust for duration of employment to account for confounding arising from the healthy worker survivor effect in occupational epidemiology.

P278 Radiation exposure in patients with inflammatory bowel disease

Abstract Background Radiological imaging plays an important role in diagnosis and follow-up of patients with IBD. Due to the progressive character of the disease, repeated imaging may be necessary. A cumulative effective dose (CED), meaning the total diagnostic radiation received, of 75 mSv is often described as the risk level one needs to try not to exceed. However, data on cumulative exposure are limited in IBD. In this retrospective study, we analysed the cumulative radiation exposure of patients with IBD in a Belgian tertiary referral centre. Methods Electronic health records (EHRs) from all IBD patients followed at the tertiary referral centre between January 1st 1990 and December 31st 2021 were searched for examinations with radiation exposure and received doses in house or in any of 27 collaborating Nexuz hospitals working with the same EHR. Both the annual effective dose (AED) and CED were calculated. A sub-analysis of patients diagnosed after January 1st 2007 was performed, as detailed radiation doses were maintained prospectively from that date onwards. Results In total, 3429 IBD patients were included. The median (IQR) AED was 0.39 (0.01-1.66) mSv/year, and was higher in patients with CD than in patients with UC [0.58 (0.01-1.81) vs. 0.17 (0.01- 1.24) mSv/year, p=0.028]. During the first 20 years after diagnosis, the received CED were found higher in patients with CD than UC (Figure, p<0.01). In 5.5% of patients, a CED ≥75 mSv was reached after a median (IQR) of 24 (13-34) years of follow-up. Sub-analysis of 1633 patients diagnosed after January 1st 2007 showed a median (IQR) AED of 0.44 (0.01- 2.12) mSv/year, again higher in patients with CD than in patients with UC [0.82 (0.02-2.38) mSv/year vs. 0.12 (0.01-1.47) mSv/year respectively, p=0.040]. Here, 3.3% patients reached a CED ≥75 mSv during a median (IQR) of 9 (6-12) years of follow-up. Most common reasons for high radiation exposure were comorbidities like malignancy and postoperative complications. Chart review by an IBD expert showed that the indication for most of these examinations was appropriate and that no alternative examination was available in a timely manner. Conclusion Up to 5.5% of patients with IBD were exposed to a CED of ≥75 mSv. Although most decisions to perform imaging with radiation exposure were appropriate, vigilance for unconsidered and excessive imaging should be maintained.

An Integrated 3-Dimentional Navigation System Increases the Accuracy, Efficiency, and Safety of Percutaneous Thoracolumbar Pedicle Screw Placement in Minimally Invasive Approaches: A Randomized Cadaveric Study.

Cadaveric study. The purpose of this study was to compare a novel, integrated 3D navigational system (NAV) and conventional fluoroscopy in the accuracy, efficiency, and radiation exposure of thoracolumbar percutaneous pedicle screw (PPS) placement. Twelve skeletally mature cadaveric specimens were obtained for twelve individual surgeons. Each participant placed bilateral PS at 11 segments, from T8 to S1. Prior to insertion, surgeons were randomized to the sequence of techniques and the side (left or right). Following placement, a CT scan of the spine was obtained for each cadaver, and an independent reviewer assessed the accuracy of screw placement using the Gertzbein grading system. Outcome metrics of interest included a comparison of breach incidence/severity, screw placement time, total procedure time, and radiation exposure between the techniques. Bivariate statistics were employed to compare outcomes at each level. A total of 262 screws (131 using each technique) were placed. The incidence of cortical breaches was significantly lower with NAV compared to FG (9% vs 18%; P = .048). Of breaches with NAV, 25% were graded as moderate or severe compared to 39% in the FG subgroup (P = .034). Median time for screw placement was significantly lower with NAV (2.7 vs 4.1 min/screw; P = .012), exclusive of registration time. Cumulative radiation exposure to the surgeon was significantly lower for NAV-guided placement (9.4 vs 134 μGy, P = .02). The use of NAV significantly decreased the incidence of cortical breaches, the severity of screw breeches, screw placement time, and radiation exposure to the surgeon when compared to traditional FG.

Transformative Precision: Investigative Summary of PET/CT-Guided Radiation Therapy Simulation in Comprehensive Cancer Management

Positron Emission Tomography/Computed Tomography (PET/CT)-guided radiation therapy simulation has transformed cancer treatment, ushering in enhanced precision and individualization. This discussion delves into clinical indications, applications, procedures, and limitations, providing a comprehensive overview across cancer types. 
 Clinical indications underscore PET/CT's role in accurate staging, target volume delineation, treatment response assessment, and post-treatment recurrence detection. Accurate staging is crucial for tailored treatment plans, while target volume delineation benefits from PET's identification of metabolic patterns. Ongoing treatment response assessment enables dynamic adjustments, and post-treatment, PET/CT aids in detecting recurrent disease. 
 Applications highlight PET/CT's treatment planning optimization by combining anatomical and functional information. Fusion of PET
 and CT images customizes radiation plans, identifying active regions for targeted delivery while sparing healthy tissues. This fusion facilitates tailored strategies, minimizing radiation exposure and enabling dynamic adaptations. 
 Procedural aspects detail imaging acquisition, image fusion, target delineation, treatment planning, and ongoing monitoring. Starting with radiotracer administration, typically fluorodeoxyglucose (FDG), PET/CT captures functional and anatomical data. Image fusion aids in target delineation and optimizing plans. Ongoing monitoring allows real-time adjustments. 
 Specific clinical applications across cancers demonstrate PET/CT's versatility. In head and neck cancers, it ensures precise delineation while avoiding critical structures. In lung cancer, it improves tumor extent identification. Similar advantages apply to lymphomas, sarcomas, brain tumors, metastatic disease, and esophageal, gastrointestinal, breast, prostate, gynecological, and pediatric cancers. 
 Limitations include spatial resolution challenges, false positives, cumulative radiation exposure, lesion size, histology, and standardization issues. Ongoing research targets spatial resolution enhancement, radiomics and AI integration, novel tracers, hybrid imaging, patient-specific dosimetry, clinical trials, multimodal workflows, cost-effectiveness, accessibility, and education. 
 PET/CT-guided radiation therapy simulation is transformative. Ongoing advancements promise a more precise and individualized approach, enhancing patient outcomes in cancer management.

Imaging swallowing function and the mechanisms driving dysphagia in inclusion body myositis.

Sporadic inclusion body myositis (IBM) is a progressive condition which commonly affects patients aged above 40. IBM does not respond to immunosuppression and no proven treatments are available. Up to 80% of patients develop some degree of swallowing impairment during the disease course. Dysphagia is a source of marked morbidity in IBM and predisposes patients to life-threatening complications such as aspiration pneumonia. The pathophysiology behind dysphagia in IBM is not fully understood. Evidence from imaging demonstrates that impaired swallowing is predominantly underpinned by oropharyngeal deficits. Changes in cricopharyngeal physiology is thought to be an important factor influencing dysphagia in IBM. However, it is unclear whether this is secondary to structural changes within the cricopharyngeus itself or driven by impairment of the muscles promoting pharyngeal clearance. The approach to dysphagia in IBM patients is limited by a lack of validated instruments to reliably assess swallowing function and an absence of effective therapeutic interventions derived from controlled trials targeting dysphagia. Imaging modalities such as the video fluoroscopic swallowing study (VFSS) are commonly used to evaluate dysphagia in IBM. Whilst VFSS is a commonly used technique in clinical practice; cumulative radiation exposure with repeated testing can be a limitation. Alternative imaging techniques could be developed further as outcome measures for assessing swallowing.In this review, we provide an overview of imaging techniques used to assess swallowing and the insight provided from such investigations into the mechanisms behind dysphagia in IBM. We suggest future directions for evaluation and outcome measurement of dysphagia in this population.

Lentigo maligna: a review.

Lentigo maligna (LM) is a melanoma in situ with distinct clinical features and histology. It commonly affects men after the sixth decade of life. Incidence rates of LM have increased based on early 21st century data from different countries; however, data are suboptimal. Data from England show a plateauing crude incidence between 2013 and 2019. By comparison, invasive melanoma and other types of melanoma insitu commonly appears in younger age groups (median age 58 and 67 years old, respectively) and incidence is rising. The most important risk factors for LM include fair skin and cumulative ultraviolet solar radiation exposure. Although LM is limited to the epidermis and connected skin adnexa, it may progress to invasive LM melanoma. The reported rate of malignant progression varies, reflecting a challenge for LM epidemiology research as often lesions are removed on diagnosis. LM poses a challenge in diagnosis and management. Although it can be diagnosed clinically or dermoscopically, histopathological assessment of biopsied skin tissue remains the gold standard. Reflectance confocal microscopy allows for better appreciation of the complexity of LM at a cellular level, often progressing beyond clinical margins. Management of LM may involve Mohs micrographic surgery or excision, although recurrence may occur even with 5 mm clinical margins. Imiquimod cream may be effective, but incomplete treatment and recurrence has been reported. Conservative management with observation or radiotherapy may be used in selected patients' cases. Five-year net survival rates are excellent. This paper reviews the natural history, epidemiology, aetiology, pathogenesis, diagnosis and management of LM.

Cumulative radiation exposure from multimodality recurrent imaging of CT, fluoroscopically guided intervention, and nuclear medicine.

To assess cumulative effective dose (CED) over a 4-year period in patients undergoing multimodality recurrent imaging at a major hospital in the USA. CED from CT, fluoroscopically guided intervention (FGI), and nuclear medicine was analyzed in consecutive exams in a tertiary care center in 2018-2021. Patients with CED ≥ 100 mSv were classified by age and body habitus (underweight, healthy weight, overweight, obese), as per body mass index percentiles < 5th, 5th to < 85th, 85th to < 95th, and ≥ 95th (age 2-19 years), and its ranges < 18.5, 18.5-24.9, 25-29.9, and ≥ 30 (≥ 20 years), respectively. Among a total of 205,425 patients, 5.7% received CED ≥ 100 mSv (mean 184 mSv, maximum 1165 mSv) and their ages were mostly 50-64 years (34.1%), followed by 65-74 years (29.8%), ≥ 75 years (19.5%), 20-49 years (16.3%), and ≤ 19 years (0.29%). Body habitus in decreasing occurrence was obese (38.6%), overweight (31.9%), healthy weight (27.5%), and underweight (2.1%). Classification by dose indicated 172 patients (≥ 500 mSv) and 3 (≥ 1000 mSv). In comparison, 5.3% of 189,030 CT patients, 1.6% of 18,963 FGI patients, and 0.19% of 41,401 nuclear-medicine patients received CED ≥ 100 mSv from a single modality. The study of total dose from CT, FGI, and nuclear medicine of patients with CED ≥ 100 mSv indicates major (89%) contribution of CT to CED with 70% of cohort being obese and overweight, and 64% of cohort aged 50-74 years. Multimodality recurrent exams are common and there is a lack of information on patient cumulative radiation exposure. This study attempts to address this lacuna and has the potential to motivate actions to improve the justification process for enhancing patient safety. • In total, 5.7% of patients undergoing multimodality recurrent imaging (CT, fluoroscopically guided intervention, nuclear medicine) incurred a dose of ≥ 100 mSv. • Mean dose was 184 mSv, with 15 to 18 times contribution from CT than that from fluoroscopically guided intervention or nuclear medicine. • In total, 70% of those who received ≥ 100mSv were either overweight or obese.

Effects of Ionizing Radiation Exposure on Cataract among Radiation Workers of Interventional Cardiology in Indonesia

Abstract Purpose The aim of this study was to determine the prevalence of radiation-induced cataracts and its correlation with radiation exposure dose and radiation protection equipment use among radiation workers of interventional cardiology. Methods This is a cross-sectional and retrospective case–control study. We included 180 subjects. The prevalence of radiation-induced cataracts was assessed using Scheimpflug analysis on the Pentacam-Oculus device. Individual cumulative radiation exposure dose and radiation protection equipment use were identified from questionnaires and personal dosimeters. Results The prevalence of radiation-induced cataracts was 16.7%. The median cumulative radiation dose was 0.8 (0.1–35.6) Gy. A positive correlation was found between cumulative radiation dose and lens density (R Spearman = 0.64). We found 83.9% of subjects used ceiling-suspended shields in 71 to 100% of their working period. However, most subjects (40.6%) did not wear protective eyewear. There was a statistically significant increasing risk of radiation-induced cataracts and unresponsive use of radiation protection equipment. Subjects using ceiling-suspended shield in only 31 to 50% of their working period increased their cataract risk by 10.8 times (95% confidence interval [CI]: 1.05–111.49, p = 0.044). Meanwhile, subjects using protective eyewear in only 51 to 70% of their working period increased their cataract risk by 8.64 times (p = 0.001). Subjects who did not wear protective eyewear had an odd ratio of 164.3 (95% CI: 19.81–1363) compared to those who did. Conclusion Radiation-induced cataracts among radiation workers of interventional cardiology depended on the radiation exposure dose and the use of radiation protection equipment.

Effect of cumulative radiation exposure from Coronary catheterization on lung cancer mortality

BackgroundCoronary catheterization (CC) procedure inevitably exposes patients with cardiovascular disease (CVD) to radiation, while cumulative radiation exposure may lead to higher risk of cancer.MethodsThis multi-center, retrospective study was based on the CC procedure in Cardiorenal ImprovemeNt II cohort (CIN-II, NCT05050877) among five regional central tertiary teaching hospitals in China between 2007 and 2020. Patients without known cancer were stratified according to the times they received CC procedure. Baseline information from their last CC procedure was analyzed. Cox regression and Fine-Gray competing risk models were used to assess the relationship between cumulative radiation exposure from CC procedures and cancer-specific, all-cause and cardiovascular mortality.ResultsOf 136,495 hospitalized survivors without cancer at baseline (mean age: 62.3 ± 11.1 years, 30.9% female), 116,992 patients (85.7%) underwent CC procedure once, 15,184 patients (11.1%) on twice, and 4,319 patients (3.2%) underwent CC procedure more than three times. During the median follow-up of 4.7 years (IQR: 2.5 to 7.4), totally 18,656 patients (13.7%) died after discharge, of which 617 (0.5%) died of lung cancer. Compared with the patients who underwent CC procedure once, the risk of lung cancer mortality increased significantly with the increase of the number of CC procedure (CC 2 times vs. 1 time: HR 1.42, 95% CI 1.13 to 1.78, P < 0.001; CC ≥ 3 times vs. 1 time: HR 1.64, 95%CI 1.13 to 2.39, P < 0.05). Similar results were observed in all-cause mortality and cardiovascular mortality, but not in other cancer-specific mortality.ConclusionsOur data suggest that substantial proportion of CVD patients are exposed to multiple high levels of low-dose ionizing radiation from CC procedure, which is associated with an increased risk of cancer mortality in this population.Trial registrationClinicalTrials.gov: NCT05050877; URL:http://www.clinicaltrials.gov; 21/09/2021.

Lowering head computed tomography radiation dose for craniosynostosis: An institutional change and review of literature

Definitive diagnosis of Craniosynostosis (CS) with computed tomography (CT) is readily available, however, exposure to ionizing radiation is often a hard stop for parents and practitioners. Lowering head CT radiation exposure helps mitigate risks and improves diagnostic utilization. The purpose of the study is to quantify radiation exposure from head CT in patients with CS using a ‘new’ (ultra-low dose) protocol; compare prior standard CT protocol; summarize published reports on cumulative radiation doses from pediatric head CT scans utilizing other low-dose protocols. A retrospective study was conducted on patients undergoing surgical correction of CS, aged less than 2 years, between August 2014 and February 2022. Cumulative effective dose (CED) in mSv was calculated, descriptive statistics were performed, and mean ± SD was reported. A literature search was conducted describing cumulative radiation exposure from head CT in pediatric patients and analyzed for ionizing radiation measurements. Forty-four patients met inclusion criteria: 17 females and 27 males. Patients who obtained head CT using the ‘New’ protocol resulted in lower CED exposure of 0.32 mSv ± 0.07 compared to the prior standard protocol at 5.25 mSv ± 2.79 (p &lt; 0.0001). Five studies specifically investigated the reduction of ionizing radiation from CT scans in patients with CS via the utilization of low-dose CT protocols. These studies displayed overall CED values ranging from 0.015 mSv to 0.77 mSv. Our new CT protocol resulted in 94% reduction of ionizing radiation. Ultra-low dose CT protocols provide similar diagnostic data without loss of bone differentiation in CS and can be easily incorporated into the workflow of a children’s hospital.

Lowering head computed tomography radiation dose for craniosynostosis: An institutional change and review of literature

Definitive diagnosis of Craniosynostosis (CS) with computed tomography (CT) is readily available, however, exposure to ionizing radiation is often a hard stop for parents and practitioners. Lowering head CT radiation exposure helps mitigate risks and improves diagnostic utilization. The purpose of the study is to quantify radiation exposure from head CT in patients with CS using a ‘new’ (ultra-low dose) protocol; compare prior standard CT protocol; summarize published reports on cumulative radiation doses from pediatric head CT scans utilizing other low-dose protocols. A retrospective study was conducted on patients undergoing surgical correction of CS, aged less than 2 years, between August 2014 and February 2022. Cumulative effective dose (CED) in mSv was calculated, descriptive statistics were performed, and mean ± SD was reported. A literature search was conducted describing cumulative radiation exposure from head CT in pediatric patients and analyzed for ionizing radiation measurements. Forty-four patients met inclusion criteria: 17 females and 27 males. Patients who obtained head CT using the ‘New’ protocol resulted in lower CED exposure of 0.32 mSv ± 0.07 compared to the prior standard protocol at 5.25 mSv ± 2.79 (p &lt; 0.0001). Five studies specifically investigated the reduction of ionizing radiation from CT scans in patients with CS via the utilization of low-dose CT protocols. These studies displayed overall CED values ranging from 0.015 mSv to 0.77 mSv. Our new CT protocol resulted in 94% reduction of ionizing radiation. Ultra-low dose CT protocols provide similar diagnostic data without loss of bone differentiation in CS and can be easily incorporated into the workflow of a children’s hospital.

Cumulative radiation exposure from radiological imaging in patients with Hodgkin and diffuse large b-cell lymphoma not submitted to radiotherapy.

To assess the cumulated exposure to radiation due to imaging in Hodgkin (HL) and diffuse large B-cell (DLBCL) lymphoma patients who were not submitted to radiotherapy. The study population included 51 and 83 adult patients with HL and DLBCL, with a follow-up duration >1 year. The cumulated exposure was expressed using patient-specific data as cumulated effective dose (CED). Fifty-one HL patients (median age 47 years) were followed for a median of 3.5 years. The median total CED per subject was 104 mSv. CT and PET/CT examinations accounted for 75 and 25% of the total CED, respectively. 26 patients (49%) had a total CED ≥ 100 mSv and the maximum CED was 302 mSv. Eighty-three DLBCL patients (median age 66 years) were followed for a median of 3.7 years. The median total CED per subject over the study period was 134 mSv. CT and PET/CT for 86% and 13% of the total CED, respectively. 56 patients (67%) had a total CED ≥100 mSv. The maximum CED was 557 mSv. Our study demonstrated the large number of imaging procedures performed for patients with lymphoma. Overall, 61% of the patients accrued a CED ≥ 100 mSv. Imaging policies were only in a partial agreement with current international guidelines. The cumulated exposure radiation exposure may be of concern in HL patients and the contribution of CT procedures to the total CED is significant. The standardisation of clinical guidelines for managing patients with lymphoma is warranted.

Radiation exposure in pediatric patients with early onset scoliosis: A longitudinal single-center study

BackgroundThere is no consensus regarding the acceptable level of medical radiation exposure in patients with early-onset scoliosis. This study aimed to quantify radiation exposure in these patients and investigate factors associated with high exposure. MethodsPatients with early-onset scoliosis who received care for their spine deformity and other comorbidities in our institution were retrospectively reviewed. Cumulative radiation exposure and total number of imaging studies were recorded. Patients with ≥30 mSv exposure were classified as high exposure and analyzed to clarify factors associated with high exposure. ResultsThirty-five patients were included for analysis. The etiology of scoliosis was idiopathic in 8 patients, congenital in 7, syndromic in 8, and neuromuscular in 12. Fifteen patients underwent 19 spinal surgeries. The types of operation performed were definitive fusion (n = 12), vertebrectomy for hemivertebra (n = 2), growing rod (n = 1), lengthening (n = 3), and revision/partial implant removal (n = 1). The mean cumulative radiation dose was 22.3 mSv (range, 2.5–94.5 mSv). Spine radiography and computed tomography combined accounted for 15.0 mSv (range, 2.4–52.5 mSv, 67.3% of the mean cumulative dose). The mean radiation dose was significantly higher in patients who underwent spinal surgery than in those who did not (31.2 mSv vs. 15.6 mSv). The high-exposure group comprised 10 patients (1 idiopathic, 1 congenital, 5 syndromic, and 3 neuromuscular scoliosis) and 8 underwent 11 spinal operations. Among 8 patients who underwent spinal surgery, the cumulative radiation dose for spine was ≥30 mSv and spine computed tomography was performed an average of 4.0 times. ConclusionsNearly one-third of patients with early-onset scoliosis and half of patients who underwent spinal surgery had >30 mSv radiation exposure due to multiple computed tomography. Medical radiation exposure and associated cancer risk should be considered when treating these patients.

Non-Contrast-Enhanced Functional Lung MRI to Evaluate Treatment Response of Allergic Bronchopulmonary Aspergillosis in Patients With Cystic Fibrosis: A Pilot Study.

Allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF) patients is associated with severe lung damage and requires specific therapeutic management. Repeated imaging is recommended to both diagnose and follow-up response to treatment of ABPA in CF. However, high risk of cumulative radiation exposure requires evaluation of free-radiation techniques in the follow-up of CF patients with ABPA. To evaluate whether Fourier decomposition (FD) functional lung MRI can detect response to treatment of ABPA in CF patients. Retrospective longitudinal. Twelve patients (7M, median-age:14 years) with CF and ABPA with pre- and post-treatment MRI. 2D-balanced-steady-state free-precession (bSSFP) sequence with FD at 1.5T. Ventilation-weighted (V) and perfusion-weighted (Q) maps were obtained after FD processing of 2D-coronal bSSFP time-resolved images acquired before and 3-9 months after treatment. Defects extent was assessed on the functional maps using a qualitative semi-quantitative score (0 = absence/negligible, 1 = <50%, 2 = >50%). Mean and coefficient of variation (CV) of the ventilation signal-intensity (VSI) and the perfusion signal-intensity (QSI) were calculated. Measurements were performed independently by three readers and averaged. Inter-reader reproducibility of the measurements was assessed. Pulmonary function tests (PFTs) were performed within 1 week of both MRI studies as markers of the airflow-limitation severity. Comparisons of medians were performed using the paired Wilcoxon-test. Reproducibility was assessed using intraclass correlation coefficient (ICC). Correlations between MRI and PFT parameters were assessed using the Spearman-test (rho correlation-coefficient). A P-value <0.05 was considered as significant. Defects extent on both V and Q maps showed a significant reduction after ABPA treatment (4.25 vs. 1.92 for V-defect-score and 5 vs. 2.75 for Q-defect-score). VSI_mean was significantly increased after treatment (280 vs. 167). Qualitative analyses reproducibility showed an ICC > 0.90, while the ICCs of the quantitative measurements was almost perfect (>0.99). Changes in VSI_cv and QSI_cv before and after treatment correlated inversely with changes of FEV1%p (rho = -0.68 for both). Non-contrast-enhanced FD lung MRI has potential to reproducibly assess response to treatment of ABPA in CF patients and correlates with PFT obstructive parameters. 4 TECHNICAL EFFICACY: Stage 3.

Risk Factors for Primary Bone Cancer After Childhood Cancer: A PanCare Childhood and Adolescent Cancer Survivor Care and Follow-Up Studies Nested Case-Control Study.

Radiation to the bone and exposure to alkylating agents increases the risk of bone cancer among survivors of childhood cancer, but there is uncertainty regarding the risks of bone tissue radiation doses below 10 Gy and the dose-response relationship for specific types of chemotherapy. Twelve European countries contributed 228 cases and 228 matched controls to a nested case-control study within a cohort of 69,460 5-year survivors of childhood cancer. Odds ratios (ORs) of developing bone cancer for different levels of cumulative radiation exposure and cumulative doses of specific types of chemotherapy were calculated. Excess ORs were calculated to investigate the shape and extent of any dose-response relationship. The OR associated with bone tissue exposed to 1-4 Gy was 4.8-fold (95% CI, 1.2 to 19.6) and to 5-9 Gy was 9.6-fold (95% CI, 2.4 to 37.4) compared with unexposed bone tissue. The OR increased linearly with increasing dose of radiation (Ptrend < .001) up to 78-fold (95% CI, 9.2 to 669.9) for doses of ≥40 Gy. For cumulative alkylating agent doses of 10,000-19,999 and ≥20,000 mg/m2, the radiation-adjusted ORs were 7.1 (95% CI, 2.2 to 22.8) and 8.3 (95% CI, 2.8 to 24.4), respectively, with independent contributions from each of procarbazine, ifosfamide, and cyclophosphamide. Other cytotoxics were not associated with bone cancer. To our knowledge, we demonstrate-for the first time-that the risk of bone cancer is increased 5- to 10-fold after exposure of bone tissue to cumulative radiation doses of 1-9 Gy. Alkylating agents exceeding 10,000 mg/m2 increase the risk 7- to 8-fold, particularly following procarbazine, ifosfamide, and cyclophosphamide. These substantially elevated risks should be used to develop/update clinical follow-up guidelines and survivorship care plans.

Estimated cumulative radiation exposure in patients treated for adolescent idiopathic scoliosis

PurposeAdolescent idiopoathic scoliosis (AIS) is a progressive spinal deformity, most often observed in female patients of pubescent age. The deformity’s severity, its progression through time, its treatment and subsequent follow-up are assessed with routine radiological evaluation of the patient’s full spine. This study aimed to determine the cumulative radiation exposure in average patients with AIS treated by brace or surgery throughout their treatment.MethodsThe average number of imaging procedures and corresponding radiation doses were retrospectively obtained from the medical charts of AIS patients treated conservatively and/or surgically at our institution. The median radiation exposure of all imaging modalities was stated in effective dose (mSv). The estimated cumulative effective radiation dose of the each treatment group was determined by multiplication of the average number of imaging conducted, and the median effective radiation dose per imaging modality.ResultsIn total, 73 AIS patients were included (28 brace, 45 surgically). Patients treated with a brace were subjected to an average of 9.03 full spine radiographs, resulting in an estimated effective cumulative dose of 0.505 mSv over a median treatment period of 3.23 years. Patients treated surgically received an average of 14.29 full spine radiographs over a median treatment period of 2.76 years. The estimated effective cumulative dose amounted from 0.951 to 1.841 mSv, depending on the surgical technique.ConclusionThe cumulative effective radiation doses rendered to AIS patients as part of their treatment and follow-up were relatively low. However, every exposure to ionising radiation for medical imaging purposes should be minimised.

Biomarkers in Lung Cancer Screening: a Narrative Review.

Although when used as a lung cancer screening tool low-dose computed tomography (LDCT) has demonstrated a significant reduction in lung cancer related mortality, it is not without pitfalls. The associated high false positive rate, inability to distinguish between benign and malignant nodules, cumulative radiation exposure, and resulting patient anxiety have all demonstrated the need for adjunctive testing in lung cancer screening. Current research focuses on developing liquid biomarkers to complement imaging as non-invasive lung cancer diagnostics. Biomarkers can be useful for both the early detection and diagnosis of disease, thereby decreasing the number of unnecessary radiologic tests performed. Biomarkers can stratify cancer risk to further enrich the screening population and augment existing risk prediction. Finally, biomarkers can be used to distinguish benign from malignant nodules in lung cancer screening. While many biomarkers require further validation studies, several, including autoantibodies and blood protein profiling, are available for clinical use. This paper describes the need for biomarkers as a lung cancer screening tool, both in terms of diagnosis and risk assessment. Additionally, this paper will discuss the goals of biomarker use, describe properties of a good biomarker, and review several of the most promising biomarkers currently being studied including autoantibodies, complement fragments, microRNA, blood proteins, circulating tumor DNA, and DNA methylation. Finally, we will describe future directions in the field of biomarker development.

Augmented reality for minimally invasive spinal surgery.

Augmented reality (AR) is an emerging technology that can overlay computer graphics onto the real world and enhance visual feedback from information systems. Within the past several decades, innovations related to AR have been integrated into our daily lives; however, its application in medicine, specifically in minimally invasive spine surgery (MISS), may be most important to understand. AR navigation provides auditory and haptic feedback, which can further enhance surgeons' capabilities and improve safety. The purpose of this article is to address previous and current applications of AR, AR in MISS, limitations of today's technology, and future areas of innovation. A literature review related to applications of AR technology in previous and current generations was conducted. AR systems have been implemented for treatments related to spinal surgeries in recent years, and AR may be an alternative to current approaches such as traditional navigation, robotically assisted navigation, fluoroscopic guidance, and free hand. As AR is capable of projecting patient anatomy directly on the surgical field, it can eliminate concern for surgeon attention shift from the surgical field to navigated remote screens, line-of-sight interruption, and cumulative radiation exposure as the demand for MISS increases. AR is a novel technology that can improve spinal surgery, and limitations will likely have a great impact on future technology.