Medium Radiation Dose Research Articles

Using CT Radiomics and Machine Learning to Distinguish Radiotherapy vs. Immune Checkpoint Inhibitor-Induced Pneumonitis in Non-Small Cell Lung Cancer Patients

Both radiotherapy (RT) and immune checkpoint inhibitors (ICIs) may induce pneumonitis which is difficult to distinguish clinically. We tested the utility of computed tomography (CT) in identifying the cause of pneumonitis in patients with non-small cell lung cancer (NSCLC) who received RT, ICIs and RT combined with ICIs (RT+ICIs). In this study, we analyzed the clinical characteristics and CT morphology of 130 NSCLC patients who developed pneumonitis after receipt of ICIs only (n = 50), thoracic RT only (n = 50) (ICIs only + RT only, the training cohort, n = 100), and RT+ICIs (the test cohort, n = 30). CT radiomics features were extracted using 3D-Slicer software and selected using LASSO regression for training a random forest (RF) classifier and a linear discriminant analysis (LDA) classifier to discern pneumonitis etiology. Patients who received RT or ICIs only were defined as the training cohort since the cause of their pneumonitis was readily identifiable. Patients who received RT+ICIs were defined as the test cohort and the cause of their pneumonitis were determined by clinicians as the ground truth. In the study, the median time from the initiation of treatment to pneumonitis was 1.9 months in RT+ICIs patients, which was shorter than 2.5 months in RT only and 2.7 months in ICIs only patients. In addition, the patients in RT+ICIs group have more high grade (grade 3-4) pneumonitis compared to patients in ICIs only or RT only group (p<0.05). Pneumonitis after the combined therapy was not a simple superposition mode of RP and CIP, resulting in the distinct characteristics of both RT and ICIs-related pneumonitis. (1) Some cases resembled RP with sharp borders in the ipsilateral lung and others resembled the bilateral distribution of typical CIP, while some patients exhibit an intermediate morphology; (2) Some pneumonitis occurred in the areas of low and medium doses of radiation rather than the high-dose radiation areas similar to RP; (3) Some pneumonitis was initially limited to the ipsilateral lung that had received radiation and then developed in bilateral lungs. The RF classifier showed favorable discrimination between CIP and RP with an area under the receiver operating curve (AUC) of 0.859 (95% CI: 0.7884-0.9292) in the training cohort and 0.851 (95% CI: 0.6998-1) in the test cohort. The simplified LDA classifier consisting of 7 LASSO-selected features achieved an AUC of 0.881 (95% CI: 0.815-0.947) in the training cohort and 0.842 (95% CI: 0.686-0.997) in the test cohort. RT and ICIs-related pneumonitis exhibit distinct clinical characteristics and morphologic features on CT. CT radiomics-based classifiers could provide a noninvasive method to identify the predominant etiology in NSCLC patients who developed pneumonitis after thoracic RT and ICIs.

Irradiation as a Promising Technology to Improve Bacteriological and Physicochemical Quality of Fish.

Fish is an excellent source of protein and other essential minerals and vitamins; nevertheless, several food-borne disease outbreaks have been linked to the consumption of different types of fish. Therefore, we aimed to overcome these health threats by evaluating gamma radiation as a good fish preservation method. The aerobic plate count (APC), identification of most common pathogenic bacteria, organoleptic properties, proximate composition, and other chemical evaluations were detected in both untreated and gamma-treated fish. The overall grades of organoleptic evaluations ranged from good to very good. Fortunately, the overall chemical analysis of all examined fish samples was accepted. For the untreated fish samples, the APC was within and above the permissible limit (5 × 107 CFU/g). Pathogenic bacteria were detected with a high prevalence rate, especially S. aureus, which was found in high percentages among examined untreated fish samples. Regarding the treated fish samples, APC and pathogenic bacterial counts were reduced in a dose-dependent manner, and the irradiation at dose 5 KGy resulted in complete eradication of the aerobic plate count (not detectable) with a mean reduction percentage equal to 100%. However, gamma irradiation has no significant effect on proximate composition; particularly, carbohydrates, proteins, and lipids were not significantly affected by low and medium doses of radiation. Therefore, gamma irradiation is a highly effective fish preservation method without any effect on fish quality. Additionally, gamma irradiation as a cold process is an attractive technology for solving the problem arising from fish-borne pathogens, and it has been purposed in this study as a cheap and safe method for reducing microbial contamination of fish.

Acquired anomalies of the coronary arteries after arterial switch operation. Usefulness of coronary computed tomography angiography and impact on follow-up.

Mortality and morbidity in patients with transposition of the great arteries after an arterial switch operation depends mainly on the status of coronary perfusion. Coronary computed tomography angiography (CCTA) provides accurate information on coronary morphology, however its use in these patients is not yet routine procedure. We sought to assess its accuracy to identify acquired coronary anomalies in this population, compared to conventional angiography in a subset of patients, and assess its impact on postoperative management. Retrospective analysis of clinical data on transposition of the great arteries in patients who underwent CCTA between January 2013 and September 2017. Between January 2013 and September 2017, 18 patients underwent CCTA. Seven patients (39%) disclosed iatrogenic coronary lesions (stenosis 1; kinking 2, occlusion 1; filiform coronary 3). The exam was performed in 78% of patients due to suggestion of myocardial ischemia (symptoms or altered exams). Only 16% needed to undergo additional exams, and in four patients the CCTA result modified therapeutic management. Conventional coronary angiography was also performed in 10 patients (55%), and in three cases, the results were discordant with underestimation or non-identification of coronary lesions on conventional angiography. The medium radiation dose used was 2.4 mSv and no complications after CT were reported. CCTA accurately identified iatrogenic postoperative coronary lesions and it has proven to be superior to conventional angiography in this population. It should be performed routinely in this group of patients, even in the absence of symptoms.

Acquired anomalies of the coronary arteries after arterial switch operation. Usefulness of coronary computed tomography angiography and impact on follow-up

IntroductionMortality and morbidity in patients with transposition of the great arteries after an arterial switch operation depends mainly on the status of coronary perfusion. Coronary computed tomography angiography (CCTA) provides accurate information on coronary morphology, however its use in these patients is not yet routine procedure. ObjectiveWe sought to assess its accuracy to identify acquired coronary anomalies in this population, compared to conventional angiography in a subset of patients, and assess its impact on postoperative management. MethodsRetrospective analysis of clinical data on transposition of the great arteries in patients who underwent CCTA between January 2013 and September 2017. ResultsBetween January 2013 and September 2017, 18 patients underwent CCTA. Seven patients (39%) disclosed iatrogenic coronary lesions (stenosis 1; kinking 2, occlusion 1; filiform coronary 3). The exam was performed in 78% of patients due to suggestion of myocardial ischemia (symptoms or altered exams). Only 16% needed to undergo additional exams, and in four patients the CCTA result modified therapeutic management.Conventional coronary angiography was also performed in 10 patients (55%), and in three cases, the results were discordant with underestimation or non-identification of coronary lesions on conventional angiography.The medium radiation dose used was 2.4 mSv and no complications after CT were reported. ConclusionCCTA accurately identified iatrogenic postoperative coronary lesions and it has proven to be superior to conventional angiography in this population. It should be performed routinely in this group of patients, even in the absence of symptoms.

High and low dose radiation effects on mammary adenocarcinoma cells - an epigenetic connection.

The successful treatment of cancer, including breast cancer, depends largely on radiation therapy and proper diagnostics. The effect of ionizing radiation on cells and tissues depends on the radiation dose and energy level, but there is insufficient evidence concerning how tumor cells respond to the low and high doses of radiation that are often used in medical diagnostic and treatment modalities. The purpose of this study was to investigate radiation-induced gene expression changes in the MCF-7 breast adenocarcinoma cell line. Using microarray technology tools, we were able to screen the differential gene expressions profiles between various radiation doses applied to MCF-7 cells. Here, we report the substantial alteration in the expression level of genes after high-dose treatment. In contrast, no dramatic gene expression alterations were noticed after the application of low and medium doses of radiation. In response to a high radiation dose, MCF-7 cells exhibited down-regulation of biological pathways such as cell cycle, DNA replication, and DNA repair and activation of the p53 pathway. Similar dose-dependent responses were seen on the epigenetic level, which was tested by a microRNA expression analysis. MicroRNA analysis showed dose-dependent radiation-induced microRNA expression alterations that were associated with cell cycle arrest and cell death. An increased rate of apoptosis was determined by an Annexin V assay. The results of this study showed that high doses of radiation affect gene expression genetically and epigenetically, leading to alterations in cell cycle, DNA replication, and apoptosis.

Influence of gamma radiation on the rheological and functional properties of bread wheats

SummaryThe effects of gamma irradiation on some biochemical, rheological and functional properties of bread wheats were studied. Two wheat cultivars were selected to represent medium‐strong and weak dough mixing strengths. Falling number values were severely depressed at doses of 500 and 1000 krad. Rheological dough properties, as assessed with the mixograph and farinograph, were also investigated. Radiation at medium doses produced an increase in the farinograph water absorption for both wheats. Radiation decreased the amount of bound water as compared to the control sample. For the medium‐strong wheat low levels of radiation produced bread with volumes and overall bread quality equal to or slightly better than those of the control flour, whereas for the weak wheat an improvement of the baking performance was obtained at all the low doses of radiation. However, the overall bread quality of both wheats was highly reduced at medium doses of radiation.