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

PURPOSE: Results of the low-dose radiation therapy (LDRT) in patients with pneumonia due to COVID-19 has been presented. METHODS: Fifteen patients received a single-fraction radiation dose of 1 Gy to the bilateral lungs due to pre-ARDS pneumonia in the course of COVID-19. Follow-up was performed on days 1, 3, 5, 7, 14 after LDRT. RESULTS: Eleven patients (73%) were released up until day 28. Median hospitalization was 20 days; 28-day mortality was 13%. Median O2 saturation improved within 24 h after LDRT in 14/15, with median SpO2 values of 84.5% vs. 87.5% p = 0.016, respectively. At day 14 of hospitalization, 46% did not require oxygen supplementation. Significant decline in CRP and IL-6 was observed within 24 h post LDRT. No organ toxicities were noted. CONCLUSION: LDRT is feasible, well tolerated and may translate to early clinical recovery in patients with severe pneumonia. Further studies are needed to determine optimal candidate, time and dose of LDRT for COVID-19 patients with pneumonia.

Clinical examples of 3D dose distribution reconstruction, based on the actual MLC leaves movement, for dynamic treatment techniques.

AIM: To present practical examples of our new algorithm for reconstruction of 3D dose distribution, based on the actual MLC leaf movement. BACKGROUND: DynaLog and RTplan files were used by DDcon software to prepare a new RTplan file for dose distribution reconstruction. MATERIALS AND METHODS: FOUR DIFFERENT CLINICALLY RELEVANT SCENARIOS WERE USED TO ASSESS THE FEASIBILITY OF THE PROPOSED NEW APPROACH: (1) Reconstruction of whole treatment sessions for prostate cancer; (2) Reconstruction of IMRT verification treatment plan; (3) Dose reconstruction in breast cancer; (4) Reconstruction of interrupted arc and complementary plan for an interrupted VMAT treatment session of prostate cancer. The applied reconstruction method was validated by comparing reconstructed and measured fluence maps. For all statistical analysis, the U Mann-Whitney test was used. RESULTS: In the first two and the fourth cases, there were no statistically significant differences between the planned and reconstructed dose distribution (p = 0.910, p = 0.975, p = 0.893, respectively). In the third case the differences were statistically significant (p = 0.015). Treatment plan had to be reconstructed. CONCLUSION: Developed dose distribution reconstruction algorithm presents a very useful QA tool. It provides means for 3D dose distribution verification in patient volume and allows to evaluate the influence of actual MLC leaf motion on the dose distribution.

The effect of tumor volume on radiotherapy outcome and correlation with other prognostic factors in patients with T2 supraglottic cancer.

The retrospective chart review of 110 patients with T2 supraglottic cancer who underwent radiotherapy was performed to correlate tumor volume with other prognostic factors and to analyze its impact on treatment results. Patients with involved nodes, poor histopathological tumor differentiation, or hemoglobin concentration ≤ 14.3 g/dl had significantly larger tumors. Patients with large tumors had significantly lower 5-year local control rate, overall survival rate and presented significantly higher risk of nodal involvement and the ratio of poor histopathological differentiation of the tumor. Tumor volume significantly impacts radiotherapy outcome and should be considered to optimize treatment strategy for patients with T2 supraglottic cancer.