Low dose radiation therapy as a potential life saving treatment for COVID-19-induced acute respiratory distress syndrome (ARDS)

Population Studies and Molecular Mechanisms of Human Radioadaptive Capabilities: Is It Time to Rethink Radiation Safety Standards?

The evolution of man on Earth took place under conditions of constant exposure to background ionizing radiation (IR). From this point of view, it would be reasonable to hypothesize the existence of adaptive mechanisms that enable the human organism to safely interact with IR at levels approximating long-term natural background levels. In some situations, the successful operation of molecular mechanisms of protection against IR is observed at values significantly exceeding the natural background level, for example, in cancer cells. In 15-25% of cancer patients, cancer cells develop a phenotype that is resistant to high doses of IR. While further investigations are warranted, the current evidence suggests a strong probability of observing positive health effects, including an increased lifespan, a reduced cancer risk, and a decreased incidence of congenital pathologies, precisely at low doses of ionizing radiation. This review offers arguments primarily based on a phenomenological approach and critically reconsidering existing methodologies for assessing the biological risks of IR to human health. Currently, in the most economically developed countries, there are radiation safety rules that interpret low-dose radiation as a clearly negative environmental factor. Nowadays, this approach may pose significant challenges to the advancement of radiomedicine and introduce complexities in the regulation of IR sources. The review also examines molecular mechanisms that may play a key role in the formation of the positive effects of low-dose IR on human radioadaptive capabilities.

Completion rates and myelosuppression degrees of cancer patients receiving radiotherapy or chemoradiotherapy unchanged regardless of delay duration after Omicron infection

This study aimed to investigate impacts of Omicron infection on cancer patients in China. A retrospective study was conducted, including 347 cancer patients undergoing radiotherapy or chemoradiotherapy between July 2022 and March 2023. Three groups involved: 108 patients without SARS-CoV-2 infection (non-COVID-19 group), 102 patients beginning treatment 10 days after first SARS-CoV-2 infection (≥ 10 days COVID-19 group), and 137 patients beginning treatment less than 10 days after first SARS-CoV-2 infection (< 10 days COVID-19 group). SAA, hsCRP, ALT, etc., were used to assess COVID-19 infection. Serum levels of SAA, hsCRP and IL-6 were all raised in two COVID-19-infected groups (SAA < 0.01, hsCRP < 0.01, IL-6 < 0.05), but PCT, ALT, LDH and HBDH levels were only elevated in ≥ 10 days COVID-19 group (PCT = 0.0478, ALT = 0.0022, LDH = 0.0313, HBDH = 0.0077). Moreover, moderate and severe infected cases were higher in ≥ 10 days COVID-19 group than < 10 days COVID-19 group (12/102 vs 5/137, p = 0.0211), but no significance in myelosuppression and completion rates among three groups. Omicron infection led to inflammation, liver and cardiovascular injury on cancer patients, but delay duration of radiotherapy or chemoradiotherapy after infection did not affect the completion rates and myelosuppression of current therapy. Besides, severity of Omicron infection was even worse among cancer patients who received delayed treatment.

Efficacy of low-dose lung radiotherapy in the management of COVID-19 patients: a randomised, open-label study

OBJECTIVE

Evaluate role of low-dose radiotherapy (LDRT) in COVID-19 pneumonia.

METHODS

Sixty-five patients 40 years or older tested positive for COVID-19 reverse transcriptase-polymerase chain reaction with mild to moderate acute respiratory distress syndrome (ARDS), were randomised 1:1, from 4 June 2021, to either best standard of care (control arm) according to the Indian Council of Medical Research guidelines or a single dose of LDRT (LDRT-0.5Gy) to both lungs along with best standard of care (experimental arm). The primary outcome was either progression to severe disease (PaO2/FiO2 ratio <100 mmHg) within 28 days of randomisation or all-cause mortality at 28 days. If the primary outcome could have been prevented, it was considered "favourable"; if not, it was considered "unfavourable."

RESULTS

Thirty-three patients were allocated to experimental arm, 32 to control arm. An intention to treat analysis was performed. Unfavourable outcome was seen in 5 (15.2%) patients in experimental arm, vs , 12 (37.5%) patients in control arm, odds of an unfavourable outcome in experimental arm were 0.3, 95% CI 0.09-0.97; two-sided p = 0.04. Four and five patients died in experimental and control arm, respectively. No radiation-induced toxicity was observed.

CONCLUSION

LDRT reduced the number of patients with unfavourable outcome at 28 days.

ADVANCES IN KNOWLEDGE

One of the few randomised studies showing reduced unfavourable outcome in mild to moderate ARDS COVID-19 patients receiving LDRT.CTRI/2021/06/034001, Clinical Trials Registry - India (ICMR-NIMS).

The impact of ionizing radiation compared to drug-induced immunological changes

Ionizing radiation (IR) activates several signaling pathways. This study shows the impact of acute low-dose IR on crucial cytokines involved in cell-mediated immunity. The immunomodulatory effects of 0.25 and 0.5 Gray (Gy) gamma rays and standard immunomodulatory drugs (cyclophosphamide) on blood counts and significant pro-inflammatory cytokines implicated in various inflammatory conditions were tested in 20 rats. Examined was the effect of acute low doses on critical cytokines, which could be utilized as an alternative to current immunosuppressive drugs. One day post-irradiation, serum levels of interferon-gamma (INF-γ), tumor necrosis factor-alpha, and interleukin-2/1-beta were measured. A 0.25 Gy exposure did not affect the detected cytokines or blood cell count compared to the nonirradiated group. On the other hand, 0.5 Gy raises the majority of the immunologically examined cytokines except for INF-γ. Except for INF-γ, cyclophosphamide reduces all of the cytokines examined. As a result, low-dose IR has a less negative influence on essential inflammatory cytokines, permitting its use. More research is needed to determine how low amounts could be used in different immunological disorders.

Low‑dose ionizing radiation attenuates high glucose‑induced hepatic apoptosis and immune factor release via modulation of a miR‑155‑SOCS1 axis

Diabetic liver injury (DLI) can result in several diseases of the liver, including steatohepatitis, liver fibrosis, cirrhosis, and liver cancer. Low‑dose ionizing radiation (LDIR) has hormetic effects in normal/disease conditions. However, whether LDIR has a beneficial effect on DLI has not been assessed previously. MicroRNA (miR)‑155 and its target gene suppressor of cytokine signaling 1 (SOCS1) play critical roles in modulating hepatic proliferation, apoptosis, and immunity. However, whether a miR‑155‑SOCS1 axis is involved in high glucose (HG) induced hepatic damage remains to be determined. In the present study, mouse hepatocyte AML12 cells were treated with 30 mM glucose (HG), 75 mGy X‑ray (LDIR), or HG plus LDIR. The expression levels of miR‑155 and SOCS1 were determined by reverse transcription‑quantitative PCR and western blotting. Additionally, apoptosis was measured using flow cytometry. The release of inflammatory factors, including TNF‑α, IL‑1β, IL‑6, IL‑10, and IFN‑γ, after HG and/or LDIR treatment was detected by ELISA. The results showed that HG may induce hepatic apoptosis by upregulating the levels of miR‑155 and downregulating the levels of SOCS1. HG also stimulated the secretion of TNF‑α, IL‑1β, IL‑6, and IL‑10. However, LDIR blocked the HG‑induced activation of a miR‑155‑SOCS1 axis and suppressed the release of inflammatory factors. These results indicated that a miR‑155‑SOCS1 axis plays a role in HG‑induced liver injury, and LDIR may exert a hepatoprotective effect by regulating the miR‑155‑SOCS1 axis.

Therapeutic potential of low dose ionizing radiation against cancer, dementia, and diabetes: evidences from epidemiological, clinical, and preclinical studies

The growing use of ionizing radiation (IR)-based diagnostic and treatment methods has been linked to increasing chronic diseases among patients and healthcare professionals. However, multiple factors such as IR dose, dose-rate, and duration of exposure influence the IR-induced chronic effects. The predicted links between low-dose ionizing radiation (LDIR) and health risks are controversial due to the non-availability of direct human studies. The studies pertaining to LDIR effects have importance in public health as exposure to background LDIR is routine. It has been anticipated that data from epidemiological and clinical reports and results of preclinical studies can resolve this controversy and help to clarify the notion of LDIR-associated health risks. Accumulating scientific literature shows reduced cancer risk, cancer-related deaths, curtailed neuro-impairments, improved neural functions, and reduced diabetes-related complications after LDIR exposure. In addition, it was found to alter evolutionarily conserved stress response pathways. However, the picture of molecular signaling pathways in LDIR responses is unclear. Besides, there is limited/no information on biomarkers of epidemiological LDIR exposure. Therefore, the present review discusses epidemiological, clinical, and preclinical studies on LDIR-induced positive effects in three chronic diseases (cancer, dementia, and diabetes) and their associated molecular mechanisms. The knowledge of LDIR response mechanisms may help to devise LDIR-based therapeutic modalities to stop disease progression. Modulation of these pathways may be helpful in developing radiation resistance among humans. However, more clinical evidence with additional biochemical, cellular, and molecular data and exploring the side effects of LDIR are the major areas of future research.

The immunomodulatory properties of low-level ionizing radiation as a potential treatment for COVID-19's life-threatening symptoms

Public health experts are looking into the current coronavirus outbreak to see if there are any ways to prevent potentially fatal symptoms. Low-Dose Radiotherapy (LD-RT) induces anti-inflammatory cytokine responses that act as a counterweight to pro-inflammatory cytokines, potentially providing therapeutic benefits for COVID-19-related diseases associated with significant morbidity and mortality. This study will look into positive immuno-radiological reactions to see if they are feasible, practicable, and effective in lowering the critical inflammatory condition of the crucial stage COVID-19. This study aims to investigate the use of low-dose lung radiation in bacterial and viral pneumonia, as well as to provide a treatment plan for COVID-19-associated pneumonia. This article discusses the evidence for and against LD-RT theories in COVID-19 patients. The use of LD-RT at various stages of COVID-19 appears to be beneficial, with fewer side effects than other currently being studied treatments.

Examine the Moderating Role of Teacher’s Self-Efficacy in the Relationship Between the Job Satisfaction and Professional Learning Community in China

Abstract

Purpose

The study aimed in examining the impact of the professional learning community, and teachers’ self-efficacy on the job satisfaction of teachers. Additionally, the study has also examined the moderating role of teachers’ self-efficacy in the relationship between the professional learning community (PLC) and job satisfaction.

Method

The SEM-PLS is employed for the data analysis. The response rate of the study is 50%. The study is carried out on the primary teachers in China.

Results

Three research questions were developed in the current study. The questions were related to the job satisfaction level of PE teachers, which was far beyond the level of satisfaction. As a result, teachers of PE classes had low performance. It was found by the study that professional learning community, job satisfaction of teachers, and self-efficacy are linked with each other. However, the results are inconclusive because of the limitation of the sample.

Implications

The study has several implications among researchers, practitioners, and teachers.

Significance

The study is among the few earlier studies on the issues related to Job Satisfaction and the professional learning community in China.

Originality/Value

The study has highlighted an important issue related to the Job Satisfaction and professional learning community in China.

The role transition of radiotherapy for the treatment of liver cancer in the COVID-19 era

The uncontrollable COVID-19 crises in the SARS-CoV-2 high-prevalence areas have greatly disrupted the routine treatment of liver cancer and triggered a role transformation of radiotherapy for liver cancer. The weight of radiotherapy in the treatment algorithm for liver cancer has been enlarged by the COVID-19 pandemic, which is helpful for the optimal risk-benefit profile.

A narrative review of COVID-19-related acute respiratory distress syndrome (CARDS): "typical" or "atypical" ARDS?

Background and Objective

The coronavirus disease of 2019 (COVID-19) is highly infectious and mainly involves the respiratory system, with some patients rapidly progress to acute respiratory distress syndrome (ARDS), which is the leading cause of death in COVID-19 patients. Hence, fully understanding the features of COVID-19-related ARDS (CARDS) and early management of this disease would improve the prognosis and reduce the mortality of severe COVID-19. With the development of recent studies which have focused on CARDS, whether CARDS is "typical" or "atypical" ARDS has become a hotly debated topic.

Methods

We searched for relevant literature from 1999 to 2021 published in PubMed by using the following keywords and their combinations: "COVID-19", "CARDS", "ARDS", "pathophysiological mechanism", "clinical manifestations", "prognosis", and "clinical trials". Then, we analyzed, compared and highlighted the differences between classic ARDS and CARDS from all of the aspects above.

Key Content and Findings

Classical ARDS commonly occurs within 1 week after a predisposing cause, yet the median time from symptoms onset to CARDS is longer than that of classical ARDS, manifesting within a period of 9.0-12.0 days. Although the lung mechanics exhibited in CARDS grossly match those of classical ARDS, there are some atypical manifestations of CARDS: the severity of hypoxemia seemed not to be proportional to injury of lung mechanics and an increase of thrombogenic processes. Meanwhile, some patients' symptoms do not correspond with the extent of the organic injury: a chest computed tomography (CT) will reveal the severe and diffuse lung injuries, yet the clinical presentations of patients can be mild.

Conclusions

Despite the differences between the CARDS and ARDS, in addition to the treatment of antivirals, clinicians should continue to follow the accepted evidence-based framework for managing all ARDS cases, including CARDS.

Covid-19 and radiotherapy: a systematic review after 2 years of pandemic

Introduction

Following the Covid-19 pandemic spread, changes in clinical practice were necessary to limit the pandemic diffusion. Also, oncological practice has undergone changes with radiotherapy (RT) treatments playing a key role.Although several experiences have been published, the aim of this review is to summarize the current evidence after 2 years of pandemic to provide useful conclusions for clinicians.

Methods

A Pubmed/MEDLINE and Embase systematic review was conducted. The search strategy was "Covid AND Radiotherapy" and only original articles in the English language were considered.

Results

A total of 2.733 papers were obtained using the mentioned search strategy. After the complete selection process, a total of 281 papers were considered eligible for the analysis of the results.

Discussion

RT has played a key role in Covid-19 pandemic as it has proved more resilient than surgery and chemotherapy. The impact of the accelerated use of hypofractionated RT and telemedicine will make these strategies central also in the post-pandemic period.

Low-dose radiotherapy combined with immunotherapy for suboral adenoid cystic carcinoma with bilateral lung metastasis: A case report and literature review

Adenoid cystic carcinoma (ACC) is a type of malignant tumor arising from the salivary glands. The tumor is characterized by a predilection for recurrence and metastasis. At present, there is no effective treatment for ACC complicated with lung metastasis. The present study reported on a case of suboral ACC with bilateral lung metastasis and the clinical features and treatment options were discussed based on a literature review. A 55-year-old female presented with suboral ACC accompanied with bilateral lung metastases. The main symptoms were masses in the right mandible and shortness of breath. Low-dose radiotherapy (LDRT) combined with immunotherapy were administered to control lung metastases. The patient is currently in a stable condition and is receiving immunotherapy. LDRT combined with immunotherapy is a feasible treatment option for such patients. Our experience with this case and the information from the literature review provide insight into the therapeutic approach for this relatively rare entity.

Assessment of bone dose response using ATR-FTIR spectroscopy: A potential method for biodosimetry

The health care application of ionizing radiation has expanded worldwide during the last several decades. While the health impacts of ionizing radiation improved patient care, inaccurate handling of radiation technology is more prone to potential health risks. Therefore, the present study characterizes the bone dose response using bovine femurs from a slaughterhouse. The gamma irradiation was designed into low-doses (0.002, 0.004 and 0.007 kGy) and high-doses (1, 10, 15, 25, 35, 50 and 60 kGy), all samples received independent doses. The combination of FTIR spectroscopy and PLS-DA allows the detection of differences in the control group and the ionizing dose, as well as distinguishing between high and low radiation doses. In this way, our findings contribute to future studies of the dose response to track ionizing radiation effects on biological systems.

Low dose radiation therapy attenuates ACE2 depression and inflammatory cytokines induction by COVID-19 viral spike protein in human bronchial epithelial cells

Purpose: Low-dose radiation therapy (LDRT) is an evidence-based anti-inflammatory treatment. In anti-COVID-19, our study suggests that low to moderate dose radiation of < 1.5 Gy can inhibit the induction of inflammatory cytokine and attenuate the ACE2 depression induced by spike protein in human bronchial epithelial cells in COVID-19 infection. Our study provided further mechanistic evidence to support LDRT as a cost-effective treatment for COVID-19 to relieve the severe inflammatory reaction and lung injury. Methods and materials: A cellular model was created by treating human bronchial epithelial cells (BEP2D) with SARS-CoV-2 spike protein. We used the qRT-PCR and ELISA analysis to identify the production of inflammatory cytokines. The BEP2D control cells and the spike-treated cells were irradiated using a single low to moderate dose radiation of 0.5 Gy, 1 Gy, and 1.5 Gy. The inflammatory cytokines and ACE2 expression were detected at different time points. Results: The soluble SARS-CoV-2 spike protein stimulated the formation of inflammatory cytokines IL-6 and TNF-α while reducing the ACE2 protein expression in human bronchial epithelial cells. A single low to moderate dose exposure of 0.5 Gy, 1 Gy, and 1.5 Gy could attenuate the IL-6 and TNF-α induction and rescue the depression of ACE2 by spike protein. Moreover, the spike protein increased the proteolytic degradation of ACE2 protein by promoting NEDD4-mediated ubiquitination of ACE2. Conclusions: The low-dose radiation can attenuate ACE2 depression and inflammatory response produced in the targeted human bronchial epithelial cells by spike protein. This coordinating effect of LDRT may relieve the severe inflammatory reaction and lung injury in COVID-19 patients.

Tea Polyphenols Prevent and Intervene in COVID-19 through Intestinal Microbiota

Although all countries have taken corresponding measures, the coronavirus disease 2019 (COVID-19) is still ravaging the world. To consolidate the existing anti-epidemic results and further strengthen the prevention and control measures against the new coronavirus, we are now actively pioneering a novel research idea of regulating the intestinal microbiota through tea polyphenols for reference. Although studies have long revealed the regulatory effect of tea polyphenols on the intestinal microbiota to various gastrointestinal inflammations, little is known about the prevention and intervention of COVID-19. This review summarizes the possible mechanism of the influence of tea polyphenols on COVID-19 mediated by the intestinal microbiota. In this review, the latest studies of tea polyphenols exhibiting their own antibacterial and anti-inflammatory activities and protective effects on the intestinal mucosal barrier are combed through and summarized. Among them, (−)-epigallocatechin-3-gallate (EGCG), one of the main monomers of catechins, may be activated as nuclear factor erythroid 2 p45-related factor 2 (Nrf2). The agent inhibits the expression of ACE2 (a cellular receptor for SARS-CoV-2) and TMPRSS2 to inhibit SARS-CoV-2 infection, inhibiting the life cycle of SARS-CoV-2. Thus, preliminary reasoning and judgments have been made about the possible mechanism of the effect of tea polyphenols on the COVID-19 control and prevention mediated by the microbiota. These results may be of great significance to the future exploration of specialized research in this field.

Estimating cancer risks due to whole lungs low dose radiotherapy with different techniques for treating COVID-19 pneumonia

BACKGROUND

Low dose radiotherapy (LDRT) of whole lungs with photon beams is a novel method for treating COVID-19 pneumonia. This study aimed to estimate cancer risks induced by lung LDRT for different radiotherapy delivery techniques.

METHOD

Four different radiotherapy techniques, including 3D-conformal with anterior and posterior fields (3D-CRT AP-PA), 3D-conformal with 8 coplanar fields (3D-CRT 8 fields), eight fields intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy using 2 full arcs (VMAT) were planned on the CT images of 32 COVID-19 patients with the prescribed dose of 1 Gy to the lungs. Organ average and maximum doses, and PTV dose distribution indexes were compared between different techniques. The radiation-induced cancer incidence and cancer-specific mortality, and cardiac heart disease risks were estimated for the assessed techniques.

RESULTS

In IMRT and VMAT techniques, heart (mean and max), breast (mean, and max), and stomach (mean) doses and also maximum dose in the body were significantly lower than the 3D-CRT techniques. The calculated conformity indexes were similar in all the techniques. However, the homogeneity indexes were lower (i.e., better) in intensity-modulated techniques (P < 0.03) with no significant differences between IMRT and VMAT plans. Lung cancer incident risks for all the delivery techniques were similar (P > 0.4). Cancer incidence and mortality risks for organs located closer to lungs like breast and stomach were higher in 3D-CRT techniques than IMRT or VMAT techniques (excess solid tumor cancer incidence risks for a 30 years man: 1.94 ± 0.22% Vs. 1.68 ± 0.17%; and women: 6.66 ± 0.81% Vs. 4.60 ± 0.43%: cancer mortality risks for 30 years men: 1.63 ± 0.19% Vs. 1.45 ± 0.15%; and women: 3.63 ± 0.44% Vs. 2.94 ± 0.23%).

CONCLUSION

All the radiotherapy techniques had low cancer risks. However, the overall estimated risks induced by IMRT and VMAT radiotherapy techniques were lower than the 3D-CRT techniques and can be used clinically in younger patients or patients having greater concerns about radiation induced cancers.

Effectiveness of low-dose radiation therapy in COVID-19 patients globally: A systematic review

Background: Novel Corona Virus Disease 2019 (COVID-19) can affect multiple organs, including the lungs, resulting in pneumonia. Apart from steroids, other anti-COVID drugs that have been studied appear to have little or no effect on COVID-19 pneumonia. There is a well-known history of inflammatory disease, including pneumonia, treated with low-dose radiation therapy (LDRT). It reduces the production of proinflammatory cytokines, Interleukin-1a (IL-1a), and leukocyte recruitment.   Methods: A comprehensive literature search was conducted using PubMed, Scopus, Embase, CINAHL, and Google Scholar, with keywords such as "radiotherapy," "low-dose radiation therapy," "low-dose irradiation," "covid-19 pneumonia," "SARS-CoV-2 pneumonia," and "covid pneumonia." with additional filters for human studies and customized articles in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We reviewed randomized controlled trials, quasi-experimental studies, cohort, case-control, and cross-sectional studies with a clearly defined intervention, including low-dose radiotherapy alone or in combination with any therapy to treat COVID-19 pneumonia from December 2019 to May 2021. Patients receiving standard or high-dose radiotherapy, including for other diseases, were excluded. Zotero software was used to collect and organize research from various databases, remove duplicates, extract relevant data, and record decisions. Participants' demographics and baseline status were obtained from the full-text articles along with the intervention's outcome/effect on patient status.  Results: Four studies with 61 participants that met the inclusion criteria were included. One was a double-blind randomized controlled trial, one a non-randomized trial, while the other two were single-arm clinical trials. Low-dose radiation therapy did not show any significant improvement in COVID-19 patients.  Conclusion: Only two studies included in this review demonstrated an improvement in inflammatory markers; however, patients were also given steroids or other drugs. Therefore, the confounding effects must be considered before drawing conclusions. This systematic review does not support mortality benefit, clinical course improvement, or imaging changes with LDRT.

A model of infection and immune response to low dose radiation

PURPOSE

Low dose radiation therapy (LDRT) using doses in the range of 30-150 cGy has been proposed as a means of mitigating the pneumonia associated with COVID-19. However, preliminary results from ongoing clinical trials have been mixed. The aim of this work is to develop a mathematical model of the viral infection and associated systemic inflammation in a patient based on the time evolution of the viral load. The model further proposes an immunomodulatory response to LDRT based on available data. Inflammation kinetics are then explored and compared to clinical results.

METHODS

The time evolution of a viral infection, inflammatory signaling factors, and inflammatory response are modeled by a set of coupled differential equations. Adjustable parameters are taken from the literature where available and otherwise iteratively adjusted to fit relevant data. Simple functions modeling both the suppression of pro-inflammatory signal factors and the enhancement of anti-inflammatory factors in response to low doses of radiation are developed. The inflammation response is benchmarked against C-reactive protein (CRP) levels measured for cohorts of patients with severe COVID-19.

RESULTS

The model fit the time-evolution of viral load data, cytokine data, and inflammation (CRP) data. When LDRT was applied early, the model predicted a reduction in peak inflammation consistent with the difference between the non-surviving and surviving cohorts. This reduction of peak inflammation diminished as the application of LDRT was delayed.

CONCLUSION

The model tracks the available data on viral load, cytokine levels, and inflammatory biomarkers well. An LDRT effect is large enough in principle to provide a life-saving immunomodulatory effect, though patients treated with LDRT already near the peak of their inflammation trajectory are unlikely to see drastic reductions in that peak. This result potentially explains some discrepancies in the preliminary clinical trial data.

Monte Carlo simulations and phantom validation of low-dose radiotherapy to the lungs using an interventional radiology C-arm fluoroscope

PURPOSE

To use MC simulations and phantom measurements to investigate the dosimetry of a kilovoltage x-ray beam from an IR fluoroscope to deliver low-dose (0.3-1.0 Gy) radiotherapy to the lungs.

MATERIALS AND METHODS

PENELOPE was used to model a 125 kV, 5.94 mm Al HVL x-ray beam produced by a fluoroscope. The model was validated through depth-dose, in-plane/cross-plane profiles and absorbed dose at 2.5-, 5.1-, 10.2- and 15.2-cm depths against the measured beam in an acrylic phantom. CT images of an anthropomorphic phantom thorax/lungs were used to simulate 0.5 Gy dose distributions for PA, AP/PA, 3-field and 4-field treatments. DVHs were generated to assess the dose to the lungs and nearby organs. Gafchromic film was used to measure doses in the phantom exposed to PA and 4-field treatments, and compared to the MC simulations.

RESULTS

Depth-dose and profile results were within 3.2% and 7.8% of the MC data uncertainty, respectively, while dose gamma analysis ranged from 0.7 to 1.0. Mean dose to the lungs were 1.1-, 0.8-, 0.9-, and 0.8- Gy for the PA, AP/PA, 3-field, and 4-field after isodose normalization to cover ∼ 95% of each lung volume. Skin dose toxicity was highest for the PA and lowest for the 4-field, and both arrangements successfully delivered the treatment on the phantom. However, the dose distribution for the PA was highly non-uniform and produced skin doses up to 4 Gy. The dose distribution for the 4-field produced a uniform 0.6 Gy dose throughout the lungs, with a maximum dose of 0.73 Gy. The average percent difference between experimental and Monte Carlo values were -0.1% (range -3% to +4%) for the PA treatment and 0.3% (range -10.3% to +15.2%) for the 4-field treatment.

CONCLUSION

A 125 kV x-ray beam from an IR fluoroscope delivered through two or more fields can deliver an effective low-dose radiotherapy treatment to the lungs. The 4-field arrangement not only provides an effective treatment, but also significant dose sparing to healthy organs, including skin, compared to the PA treatment. Use of fluoroscopy appears to be a viable alternative to megavoltage radiation therapy equipment for delivering low-dose radiotherapy to the lungs.

Carbon Ion Radiotherapy Acts as the Optimal Treatment Strategy for Unresectable Liver Cancer During the Coronavirus Disease 2019 Crisis

The coronavirus disease 2019 (COVID-19) pandemic has greatly disrupted the normal treatment of patients with liver cancer and increased their risk of death. The weight of therapeutic safety was significantly amplified for decision-making to minimize the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Herein, the safety and effectiveness of carbon ion radiotherapy (CIRT) for unresectable liver cancer (ULC) were evaluated, and Chinese experiences were shared to solve the predicament of ULC treatment caused by SARS-CoV-2. Worldwide studies were collected to evaluate CIRT for ULC as the world has become a community due to the COVID-19 pandemic. We not only searched five international databases including the Cochrane Library, Web of Science, PubMed, Embase, and Scopus but also performed supplementary retrieval with other sources. Chinese experiences of fighting against COVID-19 were introduced based on the advancements of CIRT in China and a prospective clinical trial of CIRT for treating ULC. A total of 19 studies involving 813 patients with ULC were included in the systematic review. The qualitative synthetic evaluation showed that compared with transarterial chemoembolization (TACE), CIRT could achieve superior overall survival, local control, and relative hepatic protection. The systematic results indicated that non-invasive CIRT could significantly minimize harms to patients with ULC and concurrently obtain superior anti-cancer effectiveness. According to the Chinese experience, CIRT allows telemedicine within the hospital (TMIH) to keep a sufficient person-to-person physical distance in the whole process of treatment for ULC, which is significant for cutting off the transmission route of SARS-CoV-2. Additionally, CIRT could maximize the utilization rate of hospitalization and outpatient care (UHO). Collectively, CIRT for ULC patients not only allows TMIH and the maximized UHO but also has the compatible advantages of safety and effectiveness. Therefore, CIRT should be identified as the optimal strategy for treating appropriate ULC when we need to minimize the risk of SARS-CoV-2 infection and to improve the capacity of medical service in the context of the unprecedented COVID-19 crisis.

The immunology and immunotherapy for COVID-19

The ongoing global pandemic of coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and significantly impacts the world economy and daily life. Symptoms of COVID-19 range from asymptomatic to fever, dyspnoea, acute respiratory distress and multiple organ failure. Critical cases often occur in the elderly and patients with pre-existing conditions. By binding to the angiotensin-converting enzyme 2 receptor, SARS-CoV-2 can enter and replicate in the host cell, exerting a cytotoxic effect and causing local and systemic inflammation. Currently, there is no specific treatment for COVID-19, and immunotherapy has consistently attracted attention because of its essential role in boosting host immunity to the virus and reducing overwhelming inflammation. In this review, we summarise the immunopathogenic features of COVID-19 and highlight recent advances in immunotherapy to illuminate ideas for the development of new potential therapies.

Low-dose whole-lung irradiation in severe COVID-19 pneumonia: a controlled clinical trial

INTRODUCTION

The COVID-19 pandemic has caused significant morbidity and mortality thus far. Considering the historical uses of high-voltage X-ray beams for unresolvable pneumonia, we aimed to assess whether low-dose whole-lung irradiation (WLI) could provide any benefits for patients with refractory COVID-19 pneumonia.

METHODS

Eleven patients with refractory COVID-19 pneumonia were treated with WLI to a total dose of 1 Gy and compared to 11 patients in a matched control group from June to November 2020. The study's primary endpoint was improvement of chest X-ray severity score (CXRS), followed by changes in mean oxygen (O2) saturation and 28-day mortality as secondary endpoints.

RESULTS

The final CXRS was significantly lower in the WLI group (8.7 ± 2.5) compared to the control group (12.3 ± 3.3) (P: 0.016). Change of CXRS from the first to the last chest X-ray was -2.2 ± 3.1 for the WLI group and 0.7 ± 3.9 for the control group, which showed a trend for lower CXRS in the WLI group (U = 30, p: 0.085). Mean O2 saturation showed insignificant improvement in the first 24 hours after radiotherapy (mean difference: 2.5 ± 4.1, Z=-1.6, P value: 0.11). Overall survival after 28 days was 32% in the WLI group and 11% in the control group (P: 0.48). The reason for death in many patients was not merely respiratory failure, but also other adverse situations like pneumothorax, cardiogenic shock and pulmonary thromboembolism.

CONCLUSIONS

Low-dose WLI could improve the CXR severity score and O2 saturation in severely ill COVID-19 patients, but larger studies are required to determine its impact on mortality.

Could pulmonary low-dose radiation therapy be an alternative treatment for patients with COVID-19 pneumonia? Preliminary results of a multicenter SEOR-GICOR nonrandomized prospective trial (IPACOVID trial)

PURPOSE

To evaluate the efficacy and safety of lung low-dose radiation therapy (LD-RT) for pneumonia in patients with coronavirus disease 2019 (COVID-19).

MATERIALS AND METHODS

Inclusion criteria comprised patients with COVID-19-related moderate-severe pneumonia warranting hospitalization with supplemental O2 and not candidates for admission to the intensive care unit because of comorbidities or general status. All patients received single lung dose of 0.5 Gy. Respiratory and systemic inflammatory parameters were evaluated before irradiation, at 24 h and 1 week after LD-RT. Primary endpoint was increased in the ratio of arterial oxygen partial pressure (PaO2) or the pulse oximetry saturation (SpO2) to fractional inspired oxygen (FiO2) ratio of at least 20% at 24 h with respect to the preirradiation value.

RESULTS

Between June and November 2020, 36 patients with COVID-19 pneumonia and a mean age of 84 years were enrolled. Seventeen were women and 19 were men and all of them had comorbidities. All patients had bilateral pulmonary infiltrates on chest X‑ray. All patients received dexamethasone treatment. Mean SpO2 pretreatment value was 94.28% and the SpO2/FiO2 ratio varied from 255 mm Hg to 283 mm Hg at 24 h and to 381 mm Hg at 1 week, respectively. In those who survived (23/36, 64%), a significant improvement was observed in the percentage of lung involvement in the CT scan at 1 week after LD-RT. No adverse effects related to radiation treatment have been reported.

CONCLUSIONS

LD-RT appears to be a feasible and safe option in a population with COVID-19 bilateral interstitial pneumonia in the presence of significant comorbidities.

Whole lung irradiation as a novel treatment for COVID-19: Interim results of an ongoing phase 2 trial in India

BACKGROUND AND PURPOSE

The main cause of death in COVID-19 pneumonia is acute respiratory distress syndrome which is preceded by massive cytokine release. Low-dose radiation therapy (LDRT) has anti-inflammatory and immunomodulatory effects that can interfere with the inflammatory cascade, reducing the severity of associated cytokine release.

MATERIAL & METHODS

25 patients with RT-PCR proven COVID-19 pneumonia were enrolled between November 2020 and May 2021. All patients had SpO2 < 94 % on room air, respiratory frequency > 24/min and SpO2/FiO2 ratio (SF ratio) of >89 but <357. Patients were treated according to standard COVID-19 management guidelines along with single fraction LDRT of 0.5 Gy to bilateral whole lungs within 10 days of symptom onset and 5 days of hospital admission.

RESULTS

LDRT was well tolerated by all patients. There was a statistically significant improvement in oxygenation as given by the SF ratio between pre-RT and day 2 (p < 0.05), day 3 (p < 0.001) and day 7 (p < 0.001) post RT. Demand for supplemental oxygen showed statistically significant reduction between pre-RT and day 2 (p < 0.05), day 3 (p < 0.001), day 7 (p < 0.001) post RT. 88 % patients attained clinical recovery within 10 days post LDRT and median time to hospital discharge from day of LDRT was 6 days. Three patients deteriorated and died.

CONCLUSION

As per our initial experience, LDRT appears to be a promising modality of treatment with rapid relief of respiratory distress in selected patients with moderate to severe COVID-19 pneumonia. This translates to early clinical recovery and hospital discharge in the selected patient group.

Low-dose radiation therapy (LDRT) for COVID-19 and its deadlier variants

Coronavirus variants are gaining strongholds throughout the globe. Despite early signals that SARS-CoV-2 coronavirus case numbers are easing up in the United States and during the middle of a (not so easy) vaccination roll out, the country has passed a grim landmark of 600,000 deaths. We contend that these numbers would have been much lower if the medical community undertook serious investigations into the potential of low doses of radiation (LDRT) as a mainstream treatment modality for COVID-19 pneumonia. LDRT has been posited to manifest anti-infectious and anti-inflammatory properties at doses of 0.3-1.0 Gy via the activation of the Nrf-2 pathway. Although some researchers are conducting well-designed clinical trials on the potential of LDRT, the deep-rooted, blind, and flawed acceptance of the Linear No-Threshold (LNT) model for ionizing radiation has led to sidelining of this promising therapy and thus unimaginable numbers of deaths in the United States.

[Prospects for using low-dose radiation in the complex therapy for COVID-19]

This review presents the literature data of new approaches for the treatment of COVID-19 with low doses of radiation (LDR). In addition, data on the use of LDR for the treatment of various disorders, in particular pneumonia, a number of inflammatory processes of various etiology, as well as Alzheimer's disease are discussed. The mechanisms of LDR action are briefly described, associated with the activation of the immune system and antiinflammatory response due to the effect on the processes of oxidative stress, which is reflected in an increase in the activity of cytokines (interleukin- (IL-) 6), changes in the expression of a number of genes (such as P53 and NF-κB (p65)) and long non-coding RNAs (ncRNAs) (the authors' own data are presented). Based on the analysis of the material presented, it can be assumed that further clinical trials of the effect of MDR (5-10 cGy) on patients with COVID-19, who are at different stages of the disease, will reveal the optimal conditions for the development and use of an effective treatment regimen.

Low radiation dose to treat pneumonia and other inflammations

Infection, the invasion of pathogenic microorganisms and viruses, causes reactive inflammation mediated by endogenous signals, with influx of leucocytes with distinct properties and capable of mounting a cellular or antibody response. Different forms of inflammation may also occur in response to tumours, in allergy and autoimmune disorders. Pneumonia, respiratory tract infection and septic shock for instance can arise as serious complications of the Covid-19 virus. While radiotherapy has been most widely used to control malignant tumours, it has also been used for treatment of non-malignant diseases, including acute and chronic inflammation in situations where anti-inflammatory drugs may be ineffective or contraindicated. The present review examines the history and prospects for low-dose anti-inflammatory radiation treatments, the present interest largely being motivated by the increased incidence of pulmonary disease associated Covid-19 infections. Evidence in support of the suggested efficacy are covered, together with an appraisal of one of the number of potential convenient sources that could complement external beam arrangements.

Nrf2 activation putatively mediates clinical benefits of low-dose radiotherapy in COVID-19 pneumonia and acute respiratory distress syndrome (ARDS): Novel mechanistic considerations

Novel mechanistic insights are discussed herein that link a single, nontoxic, low-dose radiotherapy (LDRT) treatment (0.5-1.0 Gy) to (1) beneficial subcellular effects mediated by the activation of nuclear factor erythroid 2-related transcription factor (Nrf2) and to (2) favorable clinical outcomes for COVID-19 pneumonia patients displaying symptoms of acute respiratory distress syndrome (ARDS). We posit that the favorable clinical outcomes following LDRT result from potent Nrf2-mediated antioxidant responses that rebalance the oxidatively skewed redox states of immunological cells, driving them toward anti-inflammatory phenotypes. Activation of Nrf2 by ionizing radiation is highly dose dependent and conforms to the features of a biphasic (hormetic) dose-response. At the cellular and subcellular levels, hormetic doses of <1.0 Gy induce polarization shifts in the predominant population of lung macrophages, from an M1 pro-inflammatory to an M2 anti-inflammatory phenotype. Together, the Nrf2-mediated antioxidant responses and the subsequent shifts to anti-inflammatory phenotypes have the capacity to suppress cytokine storms, resolve inflammation, promote tissue repair, and prevent COVID-19-related mortality. Given these mechanistic considerations-and the historical clinical success of LDRT early in the 20th century-we opine that LDRT should be regarded as safe and effective for use at almost any stage of COVID-19 infection. In theory, however, optimal life-saving potential is thought to occur when LDRT is applied prior to the cytokine storms and before the patients are placed on mechanical oxygen ventilators. The administration of LDRT either as an intervention of last resort or too early in the disease progression may be far less effective in saving the lives of ARDS patients.

Changing trend in the management of head neck cancers during the COVID-19 pandemic

BACKGROUND

In the present study, we have shared our experience in managing head neck cancers, especially the oral malignancies, during the crisis of COVID 19.

MATERIALS AND METHODS

Patients with oral cancers underwent pedicle/local flaps and free flaps reconstruction based on the availability of intensive care unit and comorbidities of the patients. The clinical outcomes were compared at the end of one week, one month, and three months after the primary surgery.

RESULTS

Pedicle/local flaps were used in 25 cases and radial/fibular free flaps were used in 8 cases for the reconstruction of soft tissue defects. Patients with pedicle flap reconstruction had better clinical outcomes, including lesser ICU stay as compared to free flaps.

CONCLUSION

Pedicle flap can be a valid alternative to the free flap for the soft tissue reconstruction in advanced oral malignancies during the COVID pandemic period in the Indian subcontinent, especially with limited infrastructure of the hospitals.

The potential for Lactoferrin to reduce SARS-CoV-2 induced cytokine storm

The COVID-19 pandemic is a serious global health threat caused by severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2). Symptoms of COVID-19 are highly variable with common hyperactivity of immune responses known as a "cytokine storm". In fact, this massive release of inflammatory cytokines into in the pulmonary alveolar structure is a main cause of mortality during COVID-19 infection. Current management of COVID-19 is supportive and there is no common clinical protocol applied to suppress this pathological state. Lactoferrin (LF), an iron binding protein, is a first line defense protein that is present in neutrophils and excretory fluids of all mammals, and is well recognized for its role in maturation and regulation of immune system function. Also, due to its ability to sequester free iron, LF is known to protect against insult-induced oxidative stress and subsequent "cytokine storm" that results in dramatic necrosis within the affected tissue. Review of the literature strongly suggests utility of LF to silence the "cytokine storm", giving credence to both prophylactic and therapeutic approaches towards combating COVID-19 infection.

COVID-19-Associated Pneumonia: Radiobiological Insights

The evolution of SARS-CoV-2 pneumonia to acute respiratory distress syndrome is linked to a virus-induced “cytokine storm”, associated with systemic inflammation, coagulopathies, endothelial damage, thrombo-inflammation, immune system deregulation and disruption of angiotensin converting enzyme signaling pathways. To date, the most promising therapeutic approaches in COVID-19 pandemic are linked to the development of vaccines. However, the fight against COVID-19 pandemic in the short and mid-term cannot only rely on vaccines strategies, in particular given the growing proportion of more contagious and more lethal variants among exposed population (the English, South African and Brazilian variants). As long as collective immunity is still not acquired, some patients will have severe forms of the disease. Therapeutic perspectives also rely on the implementation of strategies for the prevention of secondary complications resulting from vascular endothelial damage and from immune system deregulation, which contributes to acute respiratory distress and potentially to long term irreversible tissue damage. While the anti-inflammatory effects of low dose irradiation have been exploited for a long time in the clinics, few recent physiopathological and experimental data suggested the possibility to modulate the inflammatory storm related to COVID-19 pulmonary infection by exposing patients to ionizing radiation at very low doses. Despite level of evidence is only preliminary, these preclinical findings open therapeutic perspectives and are discussed in this article.

The Theoretical Value of Whole-Lung Irradiation for COVID-19 Pneumonia: A Reasonable and Safe Solution until Targeted Treatments are Developed

In this work, we considered the theoretical role of low-dose radiation therapy (approximately 0.5-1.0 Gy) in the treatment of respiratory distress syndrome associated with COVID-19 infection. Monte Carlo calculations were performed to gauge the ability to deliver low-dose radiation to the thoracic mid-plane using an orthovoltage machine. In addition, the potential harm of a single dose of 0.75 Gy (whole-lung irradiation) was assessed based on the recommendations of the BEIR-VII committee of the U.S. National Research Council. Based on the results of this work, it was determined that an orthovoltage machine (minimum 300 kVp) can be used to deliver 0.75 Gy dose to the lungs while respecting cutaneous tolerance. Using data from the BEIR-VII Committee, it is evident that the apparent benefits of such radiation treatment for patients suffering from severe manifestations of the COVID-19 infectious syndrome outweigh the potential loss of life due to radiation-induced malignancy. Although the vaccination against COVID-19 has become a reality, the spread and mortality in severely ill patients remain unacceptably high. The risk of outbreaks in the future is unknown. We suggest herein that low-dose radiotherapy at the bedside should be rigorously considered as a therapeutic option since it appears to be feasible and safe in the short and long term.

[Low dose radiotherapy for COVID-19 pneumopathy: Biological rationale and literature review]

La pandémie de coronavirus disease 2019 (covid-19) due au severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) évolue depuis un peu plus d’un an. Si la majorité des formes est bénigne, des pneumopathies graves, voire mortelles, se développent chez certains patients plus à risque. De nombreuses pistes thérapeutiques ont été explorées avec cependant trop peu d’impact sur la mortalité. C’est dans ce contexte que Kirkby et Mackenzie ont rappelé en avril 2020 les propriétés anti-inflammatoires de la radiothérapie de faible dose (délivrant moins de 1 Gy) et son utilisation dans le traitement des pneumopathies bactériennes et virales avant l’ère des antibiotiques. En effet, de larges données in vitro et in vivo ont démontré le rationnel biologique à l’origine de la diminution de l’inflammation après une radiothérapie de faible dose dans de nombreuses pathologies. Depuis un an, trois essais cliniques de phase I/II ont été publiés ainsi qu’un essai randomisé, rapportant la faisabilité et l’amélioration clinique et biologique d’un traitement bipulmonaire par une dose 0,5 à 1 Gy. Treize autres études, dont une phase III randomisée, sont en cours dans le monde. Celles-ci pourront permettre de mieux apprécier les effets de la radiothérapie de faible dose pour la pneumonie à SARS-CoV-2. Cette revue s’attache à rappeler le rationnel biologique de l’utilisation de la radiothérapie de faible dose dans les pneumopathies, et de rapporter les résultats des essais publiés ou en cours sur son utilisation spécifique pour la pneumopathie à SARS-CoV-2.

Less Can Be More: The Hormesis Theory of Stress Adaptation in the Global Biosphere and Its Implications

A dose-response relationship to stressors, according to the hormesis theory, is characterized by low-dose stimulation and high-dose inhibition. It is non-linear with a low-dose optimum. Stress responses by cells lead to adapted vitality and fitness. Physical stress can be exerted through heat, radiation, or physical exercise. Chemical stressors include reactive species from oxygen (ROS), nitrogen (RNS), and carbon (RCS), carcinogens, elements, such as lithium (Li) and silicon (Si), and metals, such as silver (Ag), cadmium (Cd), and lead (Pb). Anthropogenic chemicals are agrochemicals (phytotoxins, herbicides), industrial chemicals, and pharmaceuticals. Biochemical stress can be exerted through toxins, medical drugs (e.g., cytostatics, psychopharmaceuticals, non-steroidal inhibitors of inflammation), and through fasting (dietary restriction). Key-lock interactions between enzymes and substrates, antigens and antibodies, antigen-presenting cells, and cognate T cells are the basics of biology, biochemistry, and immunology. Their rules do not obey linear dose-response relationships. The review provides examples of biologic stressors: oncolytic viruses (e.g., immuno-virotherapy of cancer) and hormones (e.g., melatonin, stress hormones). Molecular mechanisms of cellular stress adaptation involve the protein quality control system (PQS) and homeostasis of proteasome, endoplasmic reticulum, and mitochondria. Important components are transcription factors (e.g., Nrf2), micro-RNAs, heat shock proteins, ionic calcium, and enzymes (e.g., glutathion redox enzymes, DNA methyltransferases, and DNA repair enzymes). Cellular growth control, intercellular communication, and resistance to stress from microbial infections involve growth factors, cytokines, chemokines, interferons, and their respective receptors. The effects of hormesis during evolution are multifarious: cell protection and survival, evolutionary flexibility, and epigenetic memory. According to the hormesis theory, this is true for the entire biosphere, e.g., archaia, bacteria, fungi, plants, and the animal kingdoms.

Low Doses of Radiation Increase the Immunosuppressive Profile of Lung Macrophages During Viral Infection and Pneumonia

Purpose

Severe pneumonia and acute respiratory distress syndrome (ARDS) have been described in patients with severe coronavirus disease 2019 (COVID-19). Recently, early clinical data reported the feasibility of low doses of radiation therapy (RT) in the treatment of ARDS in patients with severe COVID-19. However, the involved mechanisms remained unknown.

Methods and Materials

Here, we used airways-instilled lipopolysaccharide (LPS) and influenza virus (H1N1) as murine models of pneumonia, and toll-like receptor (TLR)-3 stimulation in human lung macrophages.

Results

Low doses of RT (0.5-1 Gray) decreased LPS-induced pneumonia, and increased the percentage of nerve- and airway-associated macrophages producing interleukin (IL) 10. During H1N1 viral infection, we observed decreased lung tissue damage and immune cell infiltration in irradiated animals. Low doses of RT increased IL-10 production by infiltrating immune cells into the lung. Irradiation of TLR-3 ligand-stimulated human lung macrophages ex vivo increased IL-10 secretion and decreased interferon γ production in the culture supernatant. The percentage of human lung macrophages producing IL-6 was also decreased.

Conclusions

Our data highlight a mechanism by which low doses of RT regulate lung inflammation and skew lung macrophages toward an anti-inflammatory profile. These data provide a preclinical mechanistic support to clinical trials evaluating low doses of RT, such as COVID-19-induced ARDS.

Diagnostic, Prognostic, and Therapeutic Use of Radiopharmaceuticals in the Context of SARS-CoV-2

The coronavirus disease 2019 (COVID-19) outbreak has devastated the healthcare systems and economies of over 200 countries in just a few months. The etiological agent of COVID-19, SARS-CoV-2, is a highly contagious virus that can be transmitted by asymptomatic and symptomatic carriers alike. While in vitro testing techniques have allowed for population-wide screening, prognostic tools are required to assess the disease severity and therapeutic response, contributing to improve the patient clinical outcomes. Moreover, no specific antiviral against COVID-19 exists at the time of publication, severely limiting treatment against the infection. Hence, there is an urgent clinical need for innovative therapeutic strategies that may contribute to manage the COVID-19 outbreak and prevent future pandemics. Herein, we critically examine recent diagnostic, prognostic, and therapeutic advancements for COVID-19 in the field of radiopharmaceuticals. First, we summarize the gold standard techniques used to diagnose COVID-19, including in vitro assays and imaging techniques, and then discuss how radionuclide-based nuclear imaging provides complementary information for prognosis and treatment management of infected patients. Second, we introduce new emerging types of radiotherapies that employ radioimmunoconjugates, which have shown selective cytotoxic response in oncological studies, and critically analyze how these compounds could be used as therapeutic agents against SARS-CoV-2. Finally, this Perspective further discusses the emerging applications of radionuclides to study the behavior of pulmonary SARS-CoV-2 aerosol particles.

New Challenges of Treatment for Locally Advanced Head and Neck Cancers in the Covid-19 Pandemic Era

Locally advanced head and neck cancer is a unique challenge for cancer management in the Covid-19 situation. The negative consequences of delaying radio-chemotherapy treatment make it necessary to prioritize these patients, the continuation of radiotherapy being indicated even if SARS-CoV-2 infection is confirmed in the case of patients with moderate and mild symptoms. For an early scenario, the standard chemo-radiotherapy using simultaneous integrated boost (SIB) technique is the preferred option, because it reduces the overall treatment time. For a late scenario with limited resources, hypo-fractionated treatment, with possible omission of chemotherapy for elderly patients and for those who have comorbidities, is recommended. Concurrent chemotherapy is controversial for dose values >2.4 Gy per fraction. The implementation of hypo-fractionated regimens should be based on a careful assessment of dose-volume constraints for organs at risks (OARs), using recommendations from clinical trials or dose conversion based on the linear-quadratic (LQ) model. Induction chemotherapy is not considered the optimal solution in this situation because of the risk of immunosuppression even though in selected groups of patients TPF regimen may bring benefits. Although the MACH-NC meta-analysis of chemotherapy in head and neck cancers did not demonstrate the superiority of induction chemotherapy over concurrent chemoradiotherapy, an induction regimen could be considered for cases with an increased risk of metastasis even in the case of a possible Covid-19 pandemic scenario.

COVID-19 pneumonia treated with ultra-low doses of radiotherapy (ULTRA-COVID study): a single institution report of two cases

Introduction

Since the outbreak of coronavirus disease 2019 (COVID-19) pandemic, healthcare systems have focused their efforts into finding a treatment to avoid the fatal outcomes of severe acute respiratory syndrome due to coronavirus‑2 (SARS-CoV-2). Benefits and risks of systemic treatments remain unclear, with multiple clinical trials still ongoing. Radiotherapy could play a role in reducing the inflammatory response in the lungs and relieve life-threatening symptoms.

Methods

We designed a prospective study of Ultra-Low Doses of Therapy with Radiation Applied to COVID-19 (ULTRA-COVID) for patients who suffer pneumonia, are not candidates for invasive mechanical ventilation and show no improvement with medical therapy.

Results

We present the preliminary results of two patients diagnosed with COVID-19 pneumonia treated with ULTRA-COVID. After one radiotherapy session, significant clinical response and a good radiological response was observed in both cases, resulting in both patients being discharged from hospital in less than 2 weeks after radiation treatment.

Conclusion

Preliminary clinical and radiological results suggest a potential benefit of treating COVID-19 pneumonia with ULTRA-COVID.

ClinicalTrials.gov Identifier: NCT04394182

[Low-dose irradiation of non-malignant diseases: Did we throw the baby out with the bathwater?]

The irradiation of non-malignant diseases, essentially for anti-inflammatory purpose, have been largely proposed and performed worldwide until the 1970-80s. At that time, the better assessment of the radio-induced malignancies, essentially in children and young patients, as well as the efficacy of the new anti-inflammatory drugs (steroids and non-steroids), led to the almost disappearance of those techniques, at least in France. In contrast, our German colleagues are still going on treating about 50,000 patients per year for non-malignant (more or less severe) diseases. After a short historical overview, the present article suggests that we were possibly going too far in the rejection of those low-dose irradiations for benign lesions. The recent emergence of new preclinical data, the better understanding of the risk of radio-induced secondary tumours (almost nil in the elderly), and the severity of some situations, such as the cytokine storm of the COVID-19, should probably lead us to reconsider those low - and sometimes very low (less than 1Gy) - irradiations for well-selected indications in the elderly.

Low-dose radiotherapy (LD-RT) for COVID-19-induced pneumopathy: a worth considering approach

PURPOSE

It seems that 2020 would be always remembered by the name of novel coronavirus (designated as SARS-CoV-2), which exerted its deteriorating effects on the health care, economy, education, and political relationships. In August 2020 more than eight hundred thousand patients lost their lives due to acute respiratory syndrome. In the limited list of therapeutic approaches, the effectiveness of low-dose radiation therapy (LD-RT) for curing inflammatory-related diseases have sparkled a light that probably this approach would bring promising advantages for COVID-19 patients. LD-RT owns its reputation from its ability to modulate the host inflammatory responses by blocking the production of pro-inflammatory cytokines and hampering the activity of leukocytes. Moreover, the cost-effective and availability of this method allow it to be applied to a large number of patients, especially those who could not receive anti-IL-6 treatments in low-income countries. But enthusiasm for applying LD-RT for the treatment of COVID-19 patients has been muted yet.

CONCLUSION

In this review, we take a look at LD-RT mechanisms of action in the treatment of nonmalignant diseases, and then through studying both the dark and bright sides of this approach, we provide a thorough discussion if LD-RT might be a promising therapeutic approach in COVID-19 patients.

Immunopathogenesis and treatment of cytokine storm in COVID-19

Severe coronavirus disease 2019 (COVID-19) is characterized by systemic hyper-inflammation, acute respiratory distress syndrome, and multiple organ failure. Cytokine storm refers to a set of clinical conditions caused by excessive immune reactions and has been recognized as a leading cause of severe COVID-19. While comparisons have been made between COVID-19 cytokine storm and other kinds of cytokine storm such as hemophagocytic lymphohistiocytosis and cytokine release syndrome, the pathogenesis of cytokine storm has not been clearly elucidated yet. Recent studies have shown that impaired response of type-1 IFNs in early stage of COVID-19 infection played a major role in the development of cytokine storm, and various cytokines such as IL-6 and IL-1 were involved in severe COVID-19. Furthermore, many clinical evidences have indicated the importance of anti-inflammatory therapy in severe COVID-19. Several approaches are currently being used to treat the observed cytokine storm associated with COVID-19, and expectations are especially high for new cytokine-targeted therapies, such as tocilizumab, anakinra, and baricitinib. Although a number of studies have been conducted on anti-inflammatory treatments for severe COVID-19, no specific recommendations have been made on which drugs should be used for which patients and when. In this review, we provide an overview of cytokine storm in COVID-19 and treatments currently being used to address it. In addition, we discuss the potential therapeutic role of extracorporeal cytokine removal to treat the cytokine storm associated with COVID-19.

Low-dose ionizing radiation as a hormetin: experimental observations and therapeutic perspective for age-related disorders

Hormesis is any kind of biphasic dose-response when low doses of some agents are beneficial while higher doses are detrimental. Radiation hormesis is the most thoroughly investigated among all hormesis-like phenomena, in particular in biogerontology. In this review, we aimed to summarize research evidence supporting hormesis through exposure to low-dose ionizing radiation (LDIR). Radiation-induced longevity hormesis has been repeatedly reported in invertebrate models such as C. elegans, Drosophila and flour beetles and in vertebrate models including guinea pigs, mice and rabbits. On the contrary, suppressing natural background radiation was repeatedly found to cause detrimental effects in protozoa, bacteria and flies. We also discussed here the possibility of clinical use of LDIR, predominantly for age-related disorders, e.g., Alzheimer's disease, for which no remedies are available. There is accumulating evidence that LDIR, such as those commonly used in X-ray imaging including computer tomography, might act as a hormetin. Of course, caution should be exercised when introducing new medical practices, and LDIR therapy is no exception. However, due to the low average residual life expectancy in old patients, the short-term benefits of such interventions (e.g., potential therapeutic effect against dementia) may outweigh their hypothetical delayed risks (e.g., cancer). We argue here that assessment and clinical trials of LDIR treatments should be given priority bearing in mind the enormous economic, social and ethical implications of potentially-treatable, age-related disorders.

Low dose radiotherapy for COVID pneumonia: Irradiate to Eradicate - Will it be possible?

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Low-dose radiotherapy for COVID-19 pneumonia treatment: case report, procedure, and literature review

BACKGROUND

The COVID-19 pandemic outbreak has set the emergency services in developing countries on major alert, as the installed response capacities are easily overwhelmed by the constantly increasing high demand. The deficit of intensive care unit beds and ventilators in countries like Peru is forcing practitioners to seek preventive or early interventional strategies to prevent saturating these chronically neglected facilities.

CASE PRESENTATION

A 64-year-old patient is reported after presenting with COVID-19 pneumonia and rapidly progressing to deteriorated ventilatory function. Compassionate treatment with a single 1‑Gy dose to the bilateral whole-lung volume was administered, with gradual daily improvement of ventilatory function and decrease in serum inflammatory markers and oxygen support needs, including intubation. No treatment-related toxicity developed. Procedures of transport, disinfection, and treatment planning and delivery are described.

CONCLUSION

Whole-lung low-dose radiotherapy seems to be a promising approach for avoiding or delaying invasive respiratory support. Delivered low doses are far from meeting toxicity ranges. On-going prospective trials will elucidate the effectiveness of this approach.

Covid-19 and leptospirosis: Cytokine storm and the use of steroids

The majority of patients with Covid-19 have a good outcome. However, complications principally of acute respiratory distress syndrome (ARDS) and multiple-organ failure can occur rapidly. Leptospirosis, a zoonotic disease, is similar to Covid-19 in that most infections are mild or asymptomatic and only a small number develop ARDS. Cytokine storm is considered to be the main incriminating factor in both. High dose steroids have been used to ameliorate the effects in leptospirosis, and similarly, reports suggest a benefit in Covid-19. SARS CoV-2 and leptospira, one a virus and the other a bacterium, are two species separated by millions of years of evolution, but producing illnesses with similar spectra, with cytokine storm being the common precipitating factor. As data are accrued from around the world, more light may be shed on features analogous to both pathways.

Prediction of COVID-19 Patients at High Risk of Progression to Severe Disease

In order to develop a novel scoring model for the prediction of coronavirus disease-19 (COVID-19) patients at high risk of severe disease, we retrospectively studied 419 patients from five hospitals in Shanghai, Hubei, and Jiangsu Provinces from January 22 to March 30, 2020. Multivariate Cox regression and orthogonal projections to latent structures discriminant analysis (OPLS-DA) were both used to identify high-risk factors for disease severity in COVID-19 patients. The prediction model was developed based on four high-risk factors. Multivariate analysis showed that comorbidity [hazard ratio (HR) 3.17, 95% confidence interval (CI) 1.96–5.11], albumin (ALB) level (HR 3.67, 95% CI 1.91–7.02), C-reactive protein (CRP) level (HR 3.16, 95% CI 1.68–5.96), and age ≥60 years (HR 2.31, 95% CI 1.43–3.73) were independent risk factors for disease severity in COVID-19 patients. OPLS-DA identified that the top five influencing parameters for COVID-19 severity were CRP, ALB, age ≥60 years, comorbidity, and lactate dehydrogenase (LDH) level. When incorporating the above four factors, the nomogram had a good concordance index of 0.86 (95% CI 0.83–0.89) and had an optimal agreement between the predictive nomogram and the actual observation with a slope of 0.95 (R² = 0.89) in the 7-day prediction and 0.96 (R² = 0.92) in the 14-day prediction after 1,000 bootstrap sampling. The area under the receiver operating characteristic curve of the COVID-19-American Association for Clinical Chemistry (AACC) model was 0.85 (95% CI 0.81–0.90). According to the probability of severity, the model divided the patients into three groups: low risk, intermediate risk, and high risk. The COVID-19-AACC model is an effective method for clinicians to screen patients at high risk of severe disease.

The risk of induced cancer and ischemic heart disease following low dose lung irradiation for COVID-19: estimation based on a virtual case

Background

Recently, low dose radiotherapy delivered to the whole lung has been proposed as treatment for the pneumonia due to COVID-19. Although there is biological plausibility for its use, the evidence supporting its effectiveness is scarce, and the risks associated with it may be significant. Thus, based on a virtual case simulation, we estimated the risks of radiation-induced cancer (RIC) and cardiac disease.

Methods

Lifetime attributable risks (LAR) of RIC were calculated for the lung, liver, esophagus, and breast of female patients. The cardiovascular risk of exposure-induced death (REID) due to ischemic heart disease was also calculated. The doses received by the organs involved in the treatment were obtained from a simulation of conformal radiotherapy (RT) treatment, delivering a dose of 0.5 Gy–1.5 Gy to the lungs. We considered a LAR and REID <1% as acceptable, 1–2% cautionary, and >2% unacceptable.

Results

The lung was at the highest risk for RIC (absolute LAR below 5200 cases/100,000 and 2250 cases/100,000 for women and men, respectively). For women, the breast had the second-highest LAR, especially for young women. The liver and esophagus had LARs below 700/100,000 for both sexes, with a higher incidence of esophageal cancer in women and liver cancer in men. Regarding the LAR cutoff, we observed an unacceptable or cautionary LAR for lung cancer in all women and men <60 years with an RT dose >1 Gy. LAR for lung cancer with an RT dose of 1 Gy was cautionary for women >60 years of age and men <40 years of age. No LAR estimation was unacceptable for the RT dose ≤0.7 Gy in all groups irrespective of sex or age at exposure. Only 0.5 Gy had an acceptable REID.

Conclusions

A RT dose ≤0.5 Gy provides an acceptable LAR estimate (≤1%) for RIC and REID, irrespective of sex and age. The current ongoing trials should initially use doses ≤0.5 Gy to maintain the risks at an acceptable level and include only patients who fail or do not have any other treatment option.

Effects of Low-Dose X-Ray on Cell Growth, Membrane Permeability, DNA Damage and Gene Transfer Efficiency

Background

We aimed to reveal if low dose X-rays would induce harmful or beneficial effect or dual response on biological cells and whether there are conditions the radiation can enhance gene transfer efficiency and promote cell growth but without damage to the cells.

Method

A systematic study was performed on the effects of Kilo-V and Mega-V X-rays on the cell morphology, viability, membrane permeability, DNA damage, and gene transfection of 293 T and CHO cells.

Results

The Kilo-V X-rays of very low doses from 0.01 to 0.04 Gray in principle didn't induce any significant change in cell morphology, growth, membrane permeability, and cause DNA damage. The Mega-V X-ray had a damage threshold between 1.0 and 1.5 Gray. The 0.25 Gray Mega-V-X-ray could promote cell growth and gene transfer, while the 1.5 Gray Mega-V X-ray damaged cells.

Conclusion

The very low dose of KV X-rays is safe to cells, while the effects of Mega-V-X-rays are dose-dependent. Mega-V-X-rays with a dose higher than the damage threshold would be harmful, that between 1.0 -1.5 Gray can evoke dual effects, whereas 0.25 Gray MV X-ray is beneficial for both cell growth and gene transfer, thus would be suitable for radiation-enhanced gene transfection.