Low-dose radiation therapy for COVID-19 pneumopathy: what is the evidence?

In the current dismal situation of the COVID-19 pandemic, effective management of patients with pneumonia and acute respiratory distress syndrome is of vital importance. Due to the current lack of effective pharmacological concepts, this situation has caused interest in (re)considering historical reports on the treatment of patients with low-dose radiation therapy for pneumonia. Although these historical reports are of low-level evidence per se, hampering recommendations for decision-making in the clinical setting, they indicate effectiveness in the dose range between 0.

[Which methods to minimize the time factor are substantiated by the evidence, which are unproven?].

Background: Several experimental studies and randomized clinical trials demonstrate a decrease of local tumor control with increasing overall treatment time of fractionated radiotherapy. Proliferation of clonogenic tumor cells most likely is the major mechanism underlying this phenomenon. Important progress in radiation oncology might therefore be expected from inhibition of proliferation of clonogenic cells during radiation treatment.

Manifestations and mechanisms of radiation-induced genomic instability in V-79 Chinese hamster cells.

Purpose: The relationship between different forms of persistent radiation damage in irradiated cells was investigated in order to identify a common underlying mechanism.

Material And Methods: V-79 Chinese hamster cells were irradiated with different doses of X-rays, neutrons and alpha-particles. In the progeny of surviving cells, up to 4 weeks after irradiation, delayed reproductive death, delayed micronuclei, delayed appearance of dicentric chromosomes and delayed apoptosis were investigated in parallel.