Smartphone application for mechanical quality assurance of medical linear accelerators

Patient-specific quality assurance on a Varian Halcyon linear accelerator using a PTW Octavius 4D device

This study investigates and validates the use of the Octavius 4D system for patient specific quality assurance on Halcyon, which is capable of rotating at 4 revolutions per minute (RPM). A commercially available PTW Octavius 4D system was used for this study which had a maximum rotation speed of 3 RPM. Initial validation included testing the accuracy of the inclinometer, percent depth doses (PDD), output factors, and dose profiles for selected static square fields. The same static fields were also subject to a gamma comparison with the TPS. This was followed by an evaluation of twelve clinical treatment plans and seven non-clinical plans with varying gantry rotation speeds. All testing was completed using detector array measurement times of 200 ms and 100 ms. Inclinometer accuracy was within 0.3° of actual gantry angle. Output factors varied less than 0.6%, PDD differences were no greater than 1.4%, and dose profile differences were less than 2.2%. Gamma pass rates for the static fields were 96.7% (2%/2mm) and 99.7% (3%/3mm). A prototype control unit, which had a maximum rotation speed of 4 RPM was also used to test the clinical and non-clinical plans. For the clinical plans, the mean gamma pass rates (2%/2mm) were 86.1% and 88.1% for the commercial unit and prototype unit respectively. Results using a measurement time of 200 ms were superior to those using 100 ms. For Halcyon deliveries greater than 3 RPM, worst case gamma results for the commercial unit were 28.6% compared to 98.5% using the prototype unit. Accurate patient specific quality assurance results can be obtained using the Octavius 4D system with a Halcyon linac, provided that the system measurement time is kept at 200 ms and the rotation speed of Halycon does not exceed 3 RPM. For higher RPM deliveries, an Octavius 4D unit with 4 RPM rotation capability is recommended.

Digital Health Solutions to Control the COVID-19 Pandemic in Countries With High Disease Prevalence: Literature Review

BACKGROUND

COVID-19, the disease caused by the novel coronavirus SARS-CoV-2, has become a global pandemic, affecting most countries worldwide. Digital health information technologies can be applied in three aspects, namely digital patients, digital devices, and digital clinics, and could be useful in fighting the COVID-19 pandemic.

OBJECTIVE

Recent reviews have examined the role of digital health in controlling COVID-19 to identify the potential of digital health interventions to fight the disease. However, this study aims to review and analyze the digital technology that is being applied to control the COVID-19 pandemic in the 10 countries with the highest prevalence of the disease.

METHODS

For this review, the Google Scholar, PubMed, Web of Science, and Scopus databases were searched in August 2020 to retrieve publications from December 2019 to March 15, 2020. Furthermore, the Google search engine was used to identify additional applications of digital health for COVID-19 pandemic control.

RESULTS

We included 32 papers in this review that reported 37 digital health applications for COVID-19 control. The most common digital health projects to address COVID-19 were telemedicine visits (11/37, 30%). Digital learning packages for informing people about the disease, geographic information systems and quick response code applications for real-time case tracking, and cloud- or mobile-based systems for self-care and patient tracking were in the second rank of digital tool applications (all 7/37, 19%). The projects were deployed in various European countries and in the United States, Australia, and China.

CONCLUSIONS

Considering the potential of available information technologies worldwide in the 21st century, particularly in developed countries, it appears that more digital health products with a higher level of intelligence capability remain to be applied for the management of pandemics and health-related crises.