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

An efficient planning technique for low dose whole lung radiation therapy for covid-19 pandemic patients

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An efficient low dose whole lung RT technique developed for severe COVID-19 patients.

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Empirical MU Calculation formula fitted from actual CT images of clinical patients.

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Acceptable dose distribution verified by 3D dose calculation in real patient anatomy.

This study aimed to establish an efficient planning technique for low dose whole lung treatment that can be implemented rapidly and safely. The treatment technique developed here relied only on chest radiograph and a simple empirical monitor unit calculation formula. The 3D dose calculation in real patient anatomy, including both nonCOVID and COVID-19 patients, which took into account tissue heterogeneity showed that the dose delivered to lungs had reasonable uniformity even with this simple and quick setup.

Low-dose radiation therapy for coronavirus disease-2019 pneumonia: Is it time to look beyond apprehensions?

Coronavirus disease-2019 (COVID-19) has become a global health crisis. Mortality associated with COVID-19 is characterized mainly by acute respiratory distress syndrome (ARDS), sepsis, pneumonia, and respiratory failure. The pathogenesis of the disease is known to be associated with pro-inflammatory processes after virus infection. Hence, various therapeutic strategies are being developed to control the inflammation and cytokine storm in COVID-19 patients. Recently, low-dose radiation therapy (LDRT) has been suggested for the treatment of pneumonia/ADRS in COVID-19 patients through irradiation of lungs by gamma/X-ray. In this direction, a few clinical trials have also been initiated. However, a few recent publications have raised some concerns regarding LDRT, especially about possibilities of activation/aggressiveness of virus (severe acute respiratory syndrome coronavirus 2 in case of COVID-19), lung injury and risk of second cancer after low-dose therapy. The present manuscript is an attempt to analyze these apprehensions based on cited references and other available literature, including some from our laboratory. At this point, LDRT may be not the first line of therapy. However, based on existing anti-inflammatory evidence of LDRT, it needs encouragement as an adjuvant therapy and for more multi-centric clinical trials. In addition, it would be worth combining LDRT with other anti-inflammatory therapies, which would open avenues for multi-modal therapy of pneumonia/ARDS in COVID-19 patients. The mode of irradiation (local lung irradiation or whole-body irradiation) and the window period after infection of the virus, need to be optimized using suitable animal studies for effective clinical outcomes of LDRT. However, considering ample evidence, it is time to look beyond the apprehensions if a low dose of radiation could be exploited for better management of COVID-19 patients.

Feasibility of Treatment Planning System in Localizing the COVID-19 Pneumonia Lesions and Evaluation of Volume Indices of Lung Involvement

Background and purpose

To assess the feasibility of a treatment planning system in localizing, contouring, and targeting lung lesions along with an evaluation of volume indices of lung involvement in patients with COVID-19 pneumonia.

Methods

We evaluated 10 patients with PCR-confirmed COVID-19 pneumonia. The CT images were imported into the ISOgray® treatment planning system to anatomically define and contour the volumes of the pulmonary lesions, the lungs, and other nearby organs.

Results

The ratio of lung lesion volume to lung volume in this study was 0.11 ± 0.13 (11.13%). The highest mean biosynthesis ratio of lung lesions was 0.36. The ratio of lesion volume in the left lung of patients with the highest volume of involvement, was 0.44, and the ratio of lesion volume in the right lung of these patients was 0.27 (approximately 1.5 times more in the left lung than the right lung). On average, CTDIvol and DLP for all patients studied in our study were 11.22 ± 2.47 mGy and 354.20 ± 65.11 mGy.cm.

Conclusion

We reported the feasibility of using a treatment planning system in localizing COVID-19 pulmonary lesions and its validity in the volumetric assessment of infected lung regions.

Mining the past to treat the present, ever mindful of the future: Low-dose radiotherapy and COVID-19 pneumonia

This editorial discusses an interim analysis of the clinical trial by Hess et al. The trial examines the use of low‐dose radiotherapy in the treatment of patients with coronavirus disease 2019 (COVID‐19) pneumonia.

Dose simulations of an early 20th century kilovoltage pneumonia radiotherapy technique performed with a modern fluoroscope

To simulate an early 20th century viral pneumonia radiotherapy treatment using modern fluoroscopy and evaluated it according to current dose guidelines. Monte Carlo was used to assess the dose distribution on an anthropomorphic phantom. Critical organs were: skin, breasts, esophagus, ribs, vertebrae, heart, thymus, and spinal cord. A 100 kV_p beam with 3 mm Al HVL, 25 × 25 cm² posterior-anterior (PA) field and 50 cm source-to-surface distance were simulated. Simulations had a resolution of 0.4 × 0.4 × 0.06 cm³ and a 6% uncertainty. Hundred percent dose was normalized to the skin surface and results were displayed in axial, coronal, and sagittal planes. Dose volume histograms were generated in MATLAB for further analysis. Prescription doses of 0.3, 0.5, and 1.0 Gy were applied to the 15% isodose for organ-dose comparison to current tolerances and potential risk of detriment. Ninety-five and ninety-seven percent of the right and left lung volumes, respectively, were well-covered by the 15% isodose line. For the 0.3, 0.5, and 1.0 Gy prescriptions, the maximum skin doses were 2.9, 4.8, and 9.6 Gy compared to a 2.0 Gy transient erythema dose threshold; left/right lung maximum doses were 1.44/1.46, 2.4/2.4, and 4.8/4.9 Gy compared to a 6.5 Gy pneumonitis and 30 Gy fibrosis thresholds; maximum heart doses were 0.5, 0.9, and 1.8 Gy compared to the 0.5 Gy ICRP-recommendation; maximum spinal cord doses were 1.4, 2.3, and 4.6 Gy compared to 7.0 Gy single fraction dose threshold. Maximum doses to other critical organs were below modern dose thresholds. A 100 kV_p PA field could deliver a 0.3 Gy or 0.5 Gy dose without risk of complications. However, a 1.0 Gy dose treatment could be problematic. Critical organ doses could be further reduced if more than one treatment field is used.

The LNT Issue Is About Politics and Economics, Not Safety

The Sykes commentary advocates “a more sensible, graded approach for protection from low dose ionizing radiation” until the LNT dose-response issue is resolved. It urges scientists to stop criticizing the LNT model that links radiation to a risk of cancer and accept regulatory use of the threshold model to “protect” people, but with higher limits. It fails to mention the 120-year history of successful low-dose treatments of a wide variety of serious diseases, including cancers. The commentary ignores published evidence of a threshold at 1.1 Gy for radiogenic leukemia and a dose-rate threshold at about 0.6 Gy per year for lifespan shortening. LNT came from politicized science, replete with scientific misconduct and conflict of interest. Its acceptance created a false cancer scare that was likely intended to stop atomic bomb testing, but it has severely damaged human welfare. Many vitally important low-dose therapies were discarded when the radiation scare was disseminated in 1956. The rapid growth of nuclear energy ended with the media-inflamed public panic after the Three Mile Island accident in 1979. Extreme implementation of the precautionary principle made it uneconomic. Availability of a low-dose therapy for lung inflammation could have dramatically decreased the impact of the COVID-19 pandemic.

Comparison of the Clinical Course of COVID-19 Pneumonia and Acute Respiratory Distress Syndrome in 2 Passengers from the Cruise Ship Diamond Princess in February 2020

BACKGROUND Patients with coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 can rapidly progress to acute respiratory distress syndrome (ARDS). Because clinical diagnosis of ARDS includes several diseases, understanding the characteristics of COVID-19-related ARDS is necessary for precise treatment. We report 2 patients with ARDS due to COVID-19-associated pneumonia. CASE REPORT Case 1 involved a 72-year-old Japanese man who presented with respiratory distress and fever. Computed tomography (CT) revealed subpleural ground-glass opacities (GGOs) and consolidation. Six days after symptom onset, reverse transcription-polymerase chain reaction (RT-PCR) testing confirmed the diagnosis of COVID-19-associated pneumonia. He was intubated and received veno-venous extracorporeal membrane oxygenation (ECMO) 8 days after symptom onset. Follow-up CT revealed large diffuse areas with a crazy-paving pattern and consolidation, which indicated progression of COVID-19-associated pneumonia. Following treatment with antiviral medications and supportive measures, the patient was weaned off ECMO after 20 days. Case 2 involved a 70-year-old Asian man residing in Canada who presented with cough, malaise, nausea, vomiting, and fever. COVID-19-associated pneumonia was diagnosed based on a positive result from RT-PCR testing. The patient was then transferred to the intensive care unit and intubated 8 days after symptom onset. Follow-up CT showed that while the initial subpleural GGOs had improved, diffuse GGOs appeared, similar to those observed upon diffuse alveolar damage. He was administered systemic steroid therapy for ARDS and extubated after 6 days. CONCLUSIONS Because the pattern of symptom exacerbation in COVID-19-associated pneumonia cases seems inconsistent, individual treatment management, especially the CT-based treatment strategy, is crucial.

Similarities between the Yin/Yang Doctrine and Hormesis in Toxicology and Pharmacology

Hormesis is a generalizable dose-response relationship characterized by low-dose stimulation and high-dose inhibition. Despite debate over this biphasic dose-response curve, hormesis is challenging central beliefs in the evaluation of chemicals or drugs and has influenced biological model selection, concentration range, study design, and hypothesis testing. We integrate the traditional Chinese philosophy - Yin/Yang doctrine - into the representation of the Western hormetic dose-response relationship and review the Yin/Yang historical philosophy contained in the hormesis concept, aiming to promote general acceptance and wider applications of hormesis. We suggest that the Yin/Yang doctrine embodies the hormetic dose-response, including the relationship between the opposing components, curve shape, and time-dependence, and may afford insights that clarify the hormetic dose-response relationship in toxicology and pharmacology.

Low Dose Radiation Therapy and Convalescent Plasma: How a Hybrid Method May Maximize Benefits for COVID-19 Patients

Physicians and scientists around the world are aggressively attempting to develop effective treatment strategies. The treatment goal is to reduce the fatality rate in 15% to 20% of individuals infected with SARS-CoV-2 who develop severe inflammatory conditions that can lead to pneumonia, and acute respiratory distress syndrome. These conditions are major causes of death in these patients. Convalescent plasma (CP) collected from patients recovered from the novel corona virus disease (COVID-19) has been considered as an effective treatment method for COVID-19. Moreover, low-dose radiation therapy (LDRT) for COVID-19 pneumonia was historically used to treat pneumonia during the first half of the 20^th century. The concept of LDRT for COVID-19 pneumonia was first introduced in March 2020. Later scientists from Canada, Spain, United States, Germany and France also confirmed the potential efficacy of LDRT for treatment of COVID-19 pneumonia. The rationale behind introducing LDRT as an effective treatment method for pneumonia in COVID-19 patients is not only due to its anti-inflammatory effect, but also in optimization of the activity of the immune system. Moreover, LDRT, unlike other treatment methods such as antiviral drugs, does not have the key disadvantage of exerting a significant selective pressure on the SARS-CoV-2 virus and hence does not lead to evolution of the virus through mutations. Given these considerations, we believe that a hybrid treatment including both CP and LDRT can trigger synergistic responses that will help healthcare providers in mitigating today’s COVID-19 pandemic.

Low dose anti-inflammatory radiotherapy for the treatment of pneumonia by covid-19: A proposal for a multi-centric prospective trial

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Interstitial bilateral pneumonia is the main complication of severe COVID-19.

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Low-dose radiation therapy (LD-RT) has well-known anti-inflammatory effects.

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LD-RT can interfere with the hyper-inflammatory cascade associated with severe COVID-19.

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LD-RT could reduce the severity of associated cytokine release caused by COVID-19.

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This trial will evaluate efficacy of lung LD-RT for interstitial COVID-19 pneumonia.

Background

COVID-19 is a highly contagious viral infection with high morbidity that is draining health resources. The biggest complication is pneumonia, which has a serious inflammatory component, with no standardized treatment. Low-dose radiation therapy (LD-RT) is non-invasive and has anti-inflammatory effects that can interfere with the inflammatory cascade, thus reducing the severity of associated cytokine release and might be useful in the treatment of respiratory complications caused by COVID-19.

Study design and methods

This multicentric prospective clinical trial seeks to evaluate the efficacy of bilateral lung LD-RT therapy as a treatment for interstitial pneumonia in patients with COVID-19 for improving respiratory function.

This prospective study will have 2 phases: I) an exploratory phase enrolling 10 patients, which will assess the feasibility and efficacy of low-dose lung irradiation, evaluated according to an increase in the PaO2/FiO2 ratio of at least 20% at 48–72 h with respect to the pre-irradiation value. If a minimum efficiency of 30% of the patients is not achieved, the study will not be continued. II) Non-randomized comparative phase in two groups: a control group, which will only receive pharmacological treatment, and an experimental arm with pharmacological treatment and LD-RT. It will include 96 patients, the allocation will be 1: 2, that is, 32 in the control arm and 64 in the experimental arm. The primary end-point will be the efficacy of LD-RT in patients with COVID-19 pneumonia according to an improvement in PaO2/FiO2. Secondary objectives will include the safety of bilateral lung LD-RT, an improvement in the radiology image, overall mortality rates at 15 and 30 days after irradiation and characterizing anti-inflammatory mechanisms of LD-RT by measuring the level of expression of adhesion molecules, anti-inflammatory cytokines and oxidative stress mediators.

Trial registration: ClinicalTrial.gov NCT-04380818 https://clinicaltrials.gov/ct2/show/NCT04380818?term=RADIOTHERAPY&cond=COVID&draw=2&rank=4.