Lung volume irradiation procedures in patients with pneumonia during COVID-19 infection – physical aspects of treatment planning and dosimetry

Abstract

Introduction. The paper presents an original, used in our Institute, method of lung volume irradiation in patients with pneumonia during COVID-19 infection. Material and methods. Procedures such as the simulation of treatment and radiotherapy are performed in a treatment room. Real time radiation treatment planning is realized as 2D planning (Irreg Planning VMS) in a separate room, and the 3D (eclipse VMS) dose distribution is calculated after the treatment. During radiation exposure, a fluence map is measured. Results. A method of irradiating the lungs of patients with COVID-19 was developed, which allows to shorten the time the patient is on the treatment table and minimize contacts between the patient and staff. Conclusions. The presented procedure made it possible to minimize the time of patient's stay in the radiotherapy department and at the same time, it retains all the required quality assurance procedures in radiotherapy treatment.

Low-Dose Radiotherapy for Patients with Pneumonia Due to COVID-19: A Single-Institution Prospective Study

“…All patients received a single-fraction radiation dose of 1 Gy to the bilateral lungs, which was delivered via an anterior–posterior and posterior–anterior beam configuration. The procedure of treatment preparation, dosimetric and quality control aspects of LDRT have been described elsewhere in detail [ 13 ]. Due to epidemiological requirements and poor general status of most of the patients, all treatment procedures were modified to be as short as possible not compromising quality assurance and were completed in 30 min, and the whole length of stay in Radiotherapy Department was not longer than 45 min with continuous oxygen support.…”

Dose estimation in patients treated with radiotherapy for SARS-COVID disease based on EPID measurement

“…A 1 Gy dose is defined at a point at a depth of ½ of the AP dimension in the geometric center of the right field beam (right lung). The irradiation time was calculated for this depth using the Eclipse Irreg module [1,2]. These calculations do not take into account tissue density and are based only on dose depth, beam specification and source to surface distance (SSD) dimensions.…”

“…The shape of the irradiation fields was copied onto the acquired 3DCBCT. 3D radiation dose distribution calculations were performed using the ECLIPSE Acuros algorithm v 16.1 [1,2]. Dose output points were selected for field 0° and 180°.…”

“…Equivalent depths should be 21.5 cm, 19.3 cm and 12.1 cm respectively for points "A", "A1" and "A2". The difference in these depths is related to the densities through which the beam's "radius" passes The sets of "K" coefficients obtained from the measurements were then compared: K (DEP) = dose [Gy] outlet / CU (measured) [3] and contrasted with the "K" factor calculated from formula [2], for the calculated coefficients "a" and "b". The Wilcoxon test was used to compare the results, which did not show statistically significant differences between them (p > 0.05).…”

“…In December 2020, the National Research Institute of Oncology in Poland, Gliwice Branch, began the irradiation of SARS-COVID patients [1,2]. A dose of 1 Gy was scheduled to the lung volume.…”