COVID-19 and radiation oncology: the experience of a two-phase plan within a single institution in central Italy.

BACKGROUND: COVID-19 in Italy has led to the need to reorganize hospital protocols with a significant risk of interruption to cancer treatment programs. In this report, we will focus on a management model covering the two phases of the COVID-19 emergency, namely lockdown-phase I and post-lockdown-phase II. METHODS: The following steps were taken in the two phases: workload during visits and radiotherapy planning, use of dedicated routes, measures for triage areas, management of suspected and positive COVID-19 cases, personal protective equipment, hospital environments and intra-institutional meetings and tumor board management. Due to the guidelines set out by the Ministry of Health, oncological follow-up visits were interrupted during the lockdown-phase I; consequently, we set about contacting patients by telephone, with laboratory and instrumental exams being viewed via telematics. During the post-lockdown-phase II, the oncological follow-up clinic reopened, with two shifts operating daily. RESULTS: By comparing our radiotherapy activity from March 9 to May 4 2019 with the same period in 2020 during full phase I of the COVID-19 emergency, similar results were achieved. First radiotherapy visits, Simulation Computed Tomography and Linear Accelerator treatments amounted to 123, 137 and 151 in 2019 compared with 121, 135 and 170 in 2020 respectively. There were no cases of COVID-19 positivity recorded either in patients or in healthcare professionals, who were all negative to the swab tests performed. CONCLUSION: During both phases of the COVID-19 emergency, the planned model used in our own experience guaranteed both continuity in radiotherapy treatments whilst neither reducing workload nor interrupting treatment and, as such, it ensured the safety of cancer patients, hospital environments and staff.

Effects of high-energy photon beam radiation therapy on Jarvik 2000 LVAD: in vitro evaluation.

PURPOSE: Left ventricular assist device (LVAD) is considered a standard care for patients with advanced heart failure. The aim of this work was to study in vitro the effects of direct exposure of the Jarvik 2000 LVAD to 10-MV photon beams. METHODS: Jarvik 2000 pump was immersed in a siliconized box filled with deionized water. A 30 × 30 × 15 cm RW3 slabs were added forth and back to the box. A treatment plan consisting of a single direct 10 × 10 cm2 field size beam was used to deliver 1000 MU at the center of the pump. During irradiation, the external Flow Maker controller and the lithium battery were positioned away from the beam. Pump parameter data (included voltage, current and frequency) were measured, recorded and analyzed for changes in pump function among baseline, pre-irradiation, during irradiation, post-irradiation and after 6 months. The whole session lasted 6 months. The Mann-Whitney U test was used to compare the repeated measurements. X-ray radiation attenuation was also studied. RESULTS: The parameters investigated remained stable over the 6 months; that is, no pump stops, alarms, events, operational changes or abnormalities during the discharge rate of the connected power sources, were encountered, confirmed by the Mann-Whitney U test applied to all sessions (p > 0.1). The measured X-ray attenuation differed from the calculated one by TPS by 34%. CONCLUSION: The Jarvik 2000 resulted stable under direct X-ray beam of 10-MV energy. Its strong attenuation, however, can affect dose deposition in the pump in TPS, and it must be taken into account.

A Feasibility Study for in vivo Dosimetry Procedure in Routine Clinical Practice.

PURPOSE: The aim of the in vivo dosimetry, during the fractionated radiation therapy, is the verification of the correct dose delivery to patient. Nowadays, in vivo dosimetry procedures for photon beams are based on the use of the electronic portal imaging device and dedicated software to elaborate electronic portal imaging device images. METHODS: In total, 8474 in vivo dosimetry tests were carried out for 386 patients treated with 3-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and volumetric modulated arc therapy techniques, using the SOFTDISO. SOFTDISO is a dedicated software that uses electronic portal imaging device images in order to (1) calculate the R index, that is, the ratio between daily reconstructed dose and the planned one at isocenter and (2) perform a γ-like analysis between the signals, S, of a reference electronic portal imaging device image and that obtained in a daily fraction. It supplies 2 indexes, the percentage γ% of points with γ < 1 and the mean γ value, γmean. In γ-like analysis, the pass criteria for the signals agreement ΔS% and distance to agreement Δd have been selected based on the clinical experience and technology used. The adopted tolerance levels for the 3 indexes were fixed in 0.95 ≤ R ≤ 1.05, γ% ≥ 90%, and γmean ≤ 0.5. RESULTS: The results of R ratio, γ-like, and a visual inspection of these data reported on a monitor screen permitted to individuate 2 classes of errors (1) class 1 that included errors due to inadequate standard quality controls and (2) class 2, due to patient morphological changes. Depending on the technique and anatomical site, a maximum of 18% of tests had at least 1 index out of tolerance; once removed the causes of class-1 errors, almost all patients (except patients with 4 lung and 2 breast cancer treated with 3-dimensional conformal radiotherapy) presented mean indexes values ([Formula: see text], [Formula: see text]%, and [Formula: see text] ) within tolerance at the end of treatment course. Class-2 errors were found in some patients. CONCLUSIONS: The in vivo dosimetry procedure with SOFTDISO resulted easily implementable, able to individuate errors with a limited workload.