Mitigating disruptions, and scalability of radiation oncology physics work during the COVID‐19 pandemic

Abstract Purpose The COVID‐19 pandemic has led to disorder in work and livelihood of a majority of the modern world. In this work, we review its major impacts on procedures and workflow of clinical physics tasks, and suggest alternate pathways to avoid major disruption or discontinuity of physics tasks in the context of small, medium, and large radiation oncology clinics. We also evaluate scalability of medical physics under the stress of “social distancing”. Methods Three models of facilities characterized by the number of clinical physicists, daily patient throughput, and equipment were identified for this purpose. For identical objectives of continuity of clinical operations, with constraints such as social distancing and unavailability of staff due to system strain, however with the possibility of remote operations, the performance of these models was investigated. General clinical tasks requiring on‐site personnel presence or otherwise were evaluated to determine the scalability of the three models at this point in the course of disease spread within their surroundings. Results The clinical physics tasks within three models could be divided into two categories. The former, which requires individual presence, include safety‐sensitive radiation delivery, high dose per fraction treatments, brachytherapy procedures, fulfilling state and nuclear regulatory commission's requirements, etc. The latter, which can be handled through remote means, include dose planning, physics plan review and supervision of quality assurance, general troubleshooting, etc. Conclusion At the current level of disease in the United States, all three models have sustained major system stress in continuing reduced operation. However, the small clinic model may not perform if either the current level of infections is maintained for long or staff becomes unavailable due to health issues. With abundance, and diversity of innovative resources, medium and large clinic models can sustain further for physics‐related radiotherapy services.


| INTRODUCTION
Coronaviruses belong to a large family of viruses that have been common in humans and many other species. The recent outbreak of the novel COVID-19 respiratory disease around the world, first detected in Wuhan, China, in 2019, is caused by a new coronavirus, called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which is the seventh coronavirus known to infect humans. 1,2 On 11 March 2020, the World Health Organization (WHO) declared the COVID-19 outbreak a pandemic. 3 As of this writing (11 April 2020), over 1.7 million confirmed infections have been reported in 210 countries and territories and two international conveyances around the world; United States with over 500,000 cases has the highest reported infections. 4 There is currently no specific treatment or vaccine for COVID- 19. Similar to influenza and other contagious respiratory diseases, to prevent illness one should avoid getting exposed to the virus which is spread by respiratory secretions of an infected individual. [5][6][7] Doremalen et al. experimentally studied the viability of SARS-CoV-2 in aerosols on various surfaces, the longest survival of contagion was observed on stainless steel and plastic with 5.6 h and 6.8 h median half-life, respectively. 8 The study concluded that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed).
As the recommendations on how to avoid the contagion continue to evolve, the US Centers for Disease Control and Prevention (CDC) provides updated general and specific guidance about the current pandemic. 9 The best approach at this moment is through "social-distancing" where physical contact is completely avoided in addition to maintaining a distance of about 6 feet (~2 m) between two individuals irrespective of the status of disease.
In the face of rapid COVID-19 spread, states, and jurisdictions have imposed restrictions on non-essential contact, and stay-at-home or shelter-in-place orders. Though, it is helpful in containing the disease and avoiding overwhelming the healthcare infrastructure, it is a serious impediment to radiation oncology physics clinical services. In a report involving 138 hospitalized COVID-19 patients in Wuhan, it was reported that 41.3% of them were presumably infected in the hospital of which 29% were hospital staff and 12.3% were patients already hospitalized for other reasons. 10 Since the COVID-19 infection risk is serious, it is crucial to prevent and control its spread in the radiation oncology departments. It is therefore necessary to set efficient and feasible prevention and control measures. Several radiation oncology centers have reported their experiences and contingency plans to counter the impact of the current pandemic on the clinical workflow. [11][12][13][14][15][16][17][18][19][20][21][22][23] Filippi et al. from Italy provided a practical guidance for radiation therapy (RT) departments based on prioritization, problem analysis, and suggested solutions. Guidelines were based on the core objective of providing availability of RT to the patients while ensuring safety of the patients, health professionals and caregivers, and on special management of suspected or COVID-19 positive cancer patients. 11 This was accomplished by staff re-organization, reduction of patients' access to RT visits through hypofractionated regimens and postponing follow-up visits. Similarly, Achard et al. emphasized the need for hypofractionated regimens, when feasible, to decrease the access of cancer patients to the hospital and limit potential diffusion of COVID-19. 12 Braunstein et al. in an effort to mitigate risk to patients and optimize resource utilization has suggested omitting, delaying, or reducing radiotherapy for breast cancer, where appropriate. 24 Marijnen et al. provided a consensus statement regarding radiotherapy options for rectal cancer during the pandemic. 25 A practice recommendation for head and neck cancer RT during the pandemic has been provided by Thomson et al. 26 Yerramilli et al. presented their departmental approach in to triaging and shortening RT for oncologic emergencies at a major comprehensive cancer center in New York City. 27 Wu et al., based on their experience in Wuhan, advised on patient and healthcare worker screening, health education, staff training, zoning, and adapting the workflow. 13  sharing experience among different centers. 15 These were adapted to a varying degree in ongoing pandemic in the United States. 16 An et al. provided a list of appropriate PPEs needed at different protection levels, which include protective cap, N95 respirator, alcohol-based disinfectant hand sanitizer (75% ethanol), goggle and face shield, sterile latex gloves, isolation gown, protective clothing, shoe covers and protective boots, surgical mask, and adult diaper. 21 According to medical physics practice guidelines, the physicists are involved to a varying degree in administration, clinical services, education, informatics, equipment performance evaluation, quality assurance, and safety. 28,29 Particularly, in a radiation oncology department, medical physicists provide supporting services to radiation oncologists (RO) and clinicians in almost all clinical scenarios. These include, but are not limited to, acceptance and commissioning of new equipment, dosimetry services, planning, patient's chart quality assurance (QA) and patient-specific QA, radiotherapy documentations, radiation safety, etc. A majority of these tasks require team work, cross-checking, direct supervising, and in some cases providing consultation and face-to-face patient interactions. 30 In a devastating situation such as the outbreak of an epidemic, wearing different hats can be very useful in mitigating the situation. During the last few weeks of the COVID-19 outbreak, the level of medical physics tasks has transitioned and evolved in such a short time that has no precedence. Even though medical physics is an integral part of radiotherapy, the emerging literature either completely lacks its prospective, or has not covered it in depth. In this work, we aim to provide an update on how various medical physics services and tasks have been adapted to new realities to accomplish the goal of RT while observing the guidance to protect the staff, patients, and personnel from either falling for the contagion or becoming a carrier for the contagion. Another objective of our work is to review changes in the light of the US healthcare model.
To this end, we will provide a comparison of three model facilities with different scales of operations to represent a major subset of medical physics practice across the United States in standing up to this challenge at this point in time. Due to the transitory nature of the COVID-19, we would caution the reader that long-term sustainability of these results is not guaranteed.

2.A | Practice stratification
We divided clinical physics practice into three main categories: small, medium, and large. A modest portion of radiation oncology in the United States is practiced in small-sized clinics with 1-2 full time equivalent (FTE) individuals responsible for the medical physics activities. Compared to a medium or large physics groups, a medical physicist is likely to be responsible for a broad range of duties, and for both implementing and overseeing a series of quality control (QC) tests and audits to ensure patient safety. For example, the small practices face challenges of effective peer-review due to costs and solitary nature of their environment. 31 The medium size clinic was defined as having 3-10 clinical physicists, with 3-6 radiotherapy linear accelerators (linacs), at least one specialized program of MRIguided RT (MRIgRT) or a clinical proton therapy, or stereotactic radiosurgery and a clinical medical physics residency program. The large clinic includes more than ten physicists, more than 6 linacs, special treatment programs, MR simulator, MRIgRT and proton therapy, and both medical physics graduate and residency education programs. The scope of services across these three models is significantly different to warrant such a stratification. Table 1 provides a snapshot of a typical spectrum of services practiced under various categories.

2.B | Level of infections and mortality
The number of reported cases with COVID-19 positive, as of this writing, continues to increase. The mortality of infected individuals is also on the rise. Figure 1

2.C | Optimization of services
The main objective of medical physics practice, for previously stated categories, continues to be safe, efficient, and uninterrupted delivery of RT while maintaining safety of all staff, patients, and caregivers during the disease outbreak. Figure 2 presents an overview of the optimization task with interdependence on constraints and resources at hand.    Team video chat with screen sharing provided required tool to review treatment plans with the physician, physicist, and dosimetrist together to improve plan quality before electronic review and plan approval.

2.C.2 | Resources
Video conferencing was also utilized for chart rounds, daily huddle, QA meetings which allowed all professionals to join from homes and/ or from their offices (no actual meeting in the conference room took place unless absolutely necessary).
Recent data suggest that SARS-CoV-2 can survive on plastic surfaces for up to 72 h; 8 hence, disinfection with wipes (containing at least 70% of ethanol), and good sanitation practices should be adopted in all physics shared areas. Shared devices such as desktop computer, keyboard, mouse, and phone were wiped as often as possible. Sanitization of all areas including the linac and HDR and console areas was done routinely, however, more stringent sanitizing protocols were already in place to clean all HDR equipments that are in contact with patients.
Housing one physicist on campus and the other working remotely helped sharing the workload while observing all constraints.
Tasks such as initial chart check, secondary dose calculations for 3D/ VMAT, weekly chart reviews, end-of-treatment chart reviews, etc.
were performed remotely. Treatment planning QA for both EBRT and HDR was also done remotely.
Patient-specific QA tasks were performed after treatment hours to minimize contact with staff and patients. Monthly QAs for the linac were performed by the physicist either over the weekend or late in the afternoon in order to minimize exposure to the pathogens. Sanitizing the work area including the linac and console area was performed after the QA.
Required physical presence during an HDR treatment was practiced by the team where the therapist, "authorized medical physicist," and "authorized user" stayed at recommended distance away from each other.
On a general note, all patients (visitors and employees) were screened every visit at the front desk with a thermometer and inquired about any symptoms and travel history before they enter the cancer center. If patients presented any symptoms, treatment was discontinued until further notice from the care provider. The physicians were advised to encourage patients with cancer-not requiring urgent RT-to postpone RT at least for three months until the epidemic subsides.
The response to COVID-19 at the medium-sized clinic involved testing the entire network stability to make sure that large number of employees can function from home with minimum interruption. Five hundred employees across the school of medicine remotely accessed the network system to perform the operability and stability test, called "pressure test". The physics team at the central campus decided to divide the physicists and the medical physics residents to two groups: on-site and off-site team, which would rotate every two weeks. Each team consisted of three physicists and two medical physics residents.
The team members were selected based on their specialties to make sure all special procedures can be covered by each group independently. All team members were equipped with laptops to work remotely. All laptops were prepared by the IT group to support remote access to Eclipse treatment planning system (Varian Medical Systems, Palo Alto, CA) and MOSAIQ record and verify system (MOSAIQ oncol- The low speed of the internet was a daily challenge for the off-site team; however the cloud system was able to maintain a reasonable level of speed to function and perform remote tasks. In one instance, a VMware crash resulted in a connection loss and an hour delay for all off-site team members. Redundancy in remote access was essential for the off-site team. One important issue was shortage of PPE and DARAFSHEH ET AL. Detailed instructions were prepared (if not already available) to facilitate training of staff. For example, in the small center, the junior physicist was trained by the senior physicist on all specialized procedures in preparation for if the senior physicist was not able to work. Possibility of recruiting a locum physicist was considered in case when physicist staff shortages appear. In the large center, in order to prepare for a possible shortage of therapists, the dosimetrists who were certified to work as a therapist were identified and the physicists fluent in treatment planning were identified to perform planning if needed.

| CONCLUSION
Clinical medical physicists play a vital role in ensuring safe and effective delivery of radiotherapy in a cancer clinic. Under disruption from COVID-19 pandemic, some aspects of the approach to medical physics tasks have rapidly changed. Overall, the approach has been to adopt a "dirty" team and a "clean" team approach in all three models.
For a small clinic model, with scarce resources a smooth operation can be established with availability of remotely accessible software, at this point in disease spread. Scope of physics services need to be modified to meet the clinical objectives; medium and large hospitals benefit from using standardized tools and large staff pools who are able to takeover in case of a major disease related staff illness.