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  Table of Contents  
PERSPECTIVE
Year : 2020  |  Volume : 57  |  Issue : 2  |  Page : 221-223
 

Time, distance, shielding and ALARA; drawing similarities between measures for radiation protection and Coronavirus disease pandemic response


1 Department of Radiation Oncology, Mahamana Pandit Madanmohan Malviya Cancer Centre and Homi Bhabha Cancer Hospital (Tata Memorial Centre), Varanasi, Uttar Pradesh, India
2 Department of Radiation Oncology, Tata Memorial Hospital, Homi Bhabha National Institute, Parel, Mumbai, India

Date of Submission16-Apr-2020
Date of Decision28-Apr-2020
Date of Acceptance28-Apr-2020
Date of Web Publication17-May-2020

Correspondence Address:
Ashutosh Mukherji
Department of Radiation Oncology, Mahamana Pandit Madanmohan Malviya Cancer Centre and Homi Bhabha Cancer Hospital (Tata Memorial Centre), Varanasi, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijc.IJC_343_20

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 » Abstract 


The practice of radiation oncology requires stringent adherence to specific steps and principles designed to minimize exposure of an individual to unnecessary doses of radiation. The basic principles of such measures to reduce the risk of exposure and limit the doses of irradiation follow the “as low as reasonably achievable ” or ALARA principle by using the concepts of time, distance and shielding. Potential exposures in radiation oncology are controlled through combination of optimal design and installation of radiation delivery equipment with well-defined standard operating procedures (SOPs). In the modern era of viral pandemics, similar principles can also be applied toward prevention of viral transmission and protection of populations at risk. In the ongoing COVID-19 pandemic, the probability of an individual getting infected is dependent on the viral load that an individual is exposed to in public spaces over a period of time. All prevention and control measures are based on preventing any such exposure to the virus, that can be achieved through limiting space for movement of the virus, using barriers and increasing distance to vulnerable surfaces, and limiting the duration of exposure. Apart from adhering to the laid-down provisions of a lock-down, preventive measures recommended for the general public include maintaining hand-hygiene, social distancing, and using facemasks to break the chain of transmission. Appropriate triage and customization of treatment protocols can help curtail hospital visits and time-spent by cancer patients during pandemic times, thereby reducing their risk of exposure as well as allowing efficient utilization of resources. The outbreak of the contagious COVID-19 pandemic threatens to disrupt healthcare systems globally with its unprecedented challenges. However, despite all the difficulties and hardships, it has also enabled new ways of learning and communication, which are likely to persist even in the post-COVID world.


Keywords: Coronavirus, exposure, protection, radiation, shielding


How to cite this article:
Mukherji A, Gupta T, Agarwal JP. Time, distance, shielding and ALARA; drawing similarities between measures for radiation protection and Coronavirus disease pandemic response. Indian J Cancer 2020;57:221-3

How to cite this URL:
Mukherji A, Gupta T, Agarwal JP. Time, distance, shielding and ALARA; drawing similarities between measures for radiation protection and Coronavirus disease pandemic response. Indian J Cancer [serial online] 2020 [cited 2020 May 28];57:221-3. Available from: http://www.indianjcancer.com/text.asp?2020/57/2/221/284473





 » Introduction Top


The practice of radiation oncology requires stringent adherence to specific steps and principles designed to minimize exposure of an individual to unwarranted and unnecessary doses of radiation. The basic principles of measures of radiation protection to reduce the risk of exposure and limit the doses of irradiation follow the “as low as reasonably achievable ” or ALARA principle[1] by using the concepts of time, distance and shielding. Potential exposures in radiation oncology are controlled through combination of optimal design and installation of radiation delivery equipment with well-defined standard operating procedures (SOPs). Distance and shielding create barriers in exposure to radiotherapy beams. Radiation exposure has an inverse square law relation with distance, and for every unit increase in distance from the source, the exposure falls by square of the distance. In the modern era of viral pandemics such as the severe acute respiratory syndrome (SARS), middle east respiratory syndrome (MERS), and now coronavirus disease (COVID-19), similar principles can also be applied towards prevention of viral transmission and protection of populations at risk. In the ongoing COVID-19 pandemic,[2] the probability of an individual getting infected is dependent on the viral load that an individual is exposed to in public spaces over a period of time. All prevention and control measures are based on preventing any such exposure to the virus, that can be achieved through limiting space for movement of the virus, using barriers and increasing distance to vulnerable surfaces, and limiting the duration of exposure. The clamping of a lockdown discourages non-essential movement of people thereby decreasing crowding of public places and ensuring social distancing. Apart from adhering to the laid-down provisions of a lockdown, preventive measures recommended for the general public include maintaining personal and hand-hygiene, observing social distancing norms, and using personal protective equipment (PPE) such as simple face-masks to break the chain of transmission. Appropriate triage of cancer patients with considered change in existing treatment paradigms through reassessment of benefit-risk ratio is likely to be necessary to allow more efficient utilization of resources to tide over the present crisis. Coping with crisis requires strong leadership, war-like preparedness, efficient use of resources, and clear communication with all relevant stakeholders.[3] Institutions and departments need to have proper contingency planning to create capacity and continue to provide essential services despite reduced workforce.

COVID-19 control as measures of time

Decreasing the duration of time an individual is exposed to in a compromised environment will decrease the expected load of viral exposure. During pandemic times, cancer patients must be triaged and prioritized based on their diagnosis, prognosis and urgency for initiating treatment. Patients coming for routine consultation and follow-up assessments should be actively discouraged to travel to the healthcare facility, but instead be provided virtual or remote telephonic or video-consultation.[4] Such virtual consultations can also be extended to patients who seek expert opinion through online portals. Clinical decision-making for individual patients should continue to be done through multi-disciplinary joint clinics which should be attended only by key personnel or better still through virtual tumor boards. Keeping punctuality for appointments and consultation timings will aid in decongestion of the out-patient clinics. Routine follow-up investigations can be postponed to a later date or even avoided if not necessary. Appropriate modification of chemotherapy regimens (drugs, dose, and cycling) may be considered to reduce the frequency of visits and need for hospital admission or aggressive supportive care, without negative impact upon cancer outcomes. The radiation oncology community has been at the forefront of systematically testing hypo-fractionated radiotherapy schedules in several solid cancers (lung, breast, head-neck, prostate), given the fact short-course treatments are associated with cost-effectiveness, patient/care-giver convenience and better compliance. Appropriate use of such curative-intent altered fractionation schedules should be considered during pandemic times, including for palliative radiotherapy for symptom relief that can be delivered most of the times either as a single fraction or once-weekly regimens. A recent consensus document[5] providing detailed measures for each cancer site/type, applicable dose-constraints, and plan evaluation criteria is a valuable resource for guidance during the ongoing COVID-19 crisis.

COVID-19 control as measures of distance

The basic principle is to keep as much distance as possible or avoid to the extent possible any contact with suspected/infected COVID-19 patients. This is because the aerosols generated by the virus are thought to be suspended in air for a maximum of 30-40 minutes before sinking to the ground; and can reach a distance of 6-8 feet during sneezing, 3-5 feet during cough and 1-2 feet during normal expiration, as per WHO models.[6] High-risk individuals within the workforce such as those with comorbidities including uncontrolled hypertension, diabetes mellitus, pregnant individuals, or patients with pulmonary conditions should be advised to stay away from areas of direct exposure, but can still help in administrative work either from home or from office. The number of healthcare workers at any given time can be controlled through appropriate rotation of staff (eg., Alternate day roster) or as suited for the departmental workflow. Academic activities and teaching sessions continue through online resources and webinars.

Patients should be adequately screened and triaged before they enter the hospital premises. Patients with fever and/or respiratory symptoms should be initially evaluated in a “fever clinic ” for appropriate triage according to existing institutional guidelines and SOPs.[3] In a radiotherapy department, the concept of social distancing can be further used by scheduling appointments on a staggered basis throughout the day to avoid congestion at the machine-waiting area, judicious use of hypo-fractionated schedules and on-board imaging to reduce treatment times, and distributing patients on all available treatment machines to reduce overcrowding on any particular machine. The admission of patients suspected of or infected with COVID-19 in oncology or radiotherapy departments should be discouraged, who should be managed in separate isolation facility either within the institute or dedicated COVID hospitals with appropriate safeguards to prevent cross-infection.

COVID-19 control as measures of shielding

Shielding methods can be used to protect both healthcare workers and the general population from those at risk. During consultation or review of asymptomatic patients, attending healthcare workers should use appropriate safeguards in the form of PPE (surgical masks and gloves) and maintain a minimum distance of at least 3 feet from patients and their care-givers who can be potential source(s) of infection. Asymptomatic COVID-19 positive patients suffering from category 1 cancers mandating early definitive radiotherapy (squamous cancer of head-neck or cervix) may be allowed to continue ongoing fractionated radiotherapy treatment ideally on a separate machine, but definitely, at a particular time-slot at the end of the day with full-body PPE (N95 mask, goggles, face-shield, body-suit, shoe-cover) for the involved healthcare providers (doctors, nurses, technicians) and adequate barrier precautions for the patient. In symptomatic patients with proven COVID-19 infection, active anticancer treatment may be deferred temporarily till they are deemed cured and non-contagious by local health bodies.


 » Conclusion Top


The outbreak of the contagious COVID-19 pandemic threatens to disrupt healthcare systems globally in terms of capacity and resources. It has brought in certain unprecedented and unique challenges that need collective thinking and brainstorming. However, despite all the difficulties and hardships, it has also enabled new ways of learning and communication, which are likely to persist even in the post-COVID world.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
 » References Top

1.
Ortiz-Lopez P, Rajan G, Podgorsak EB. In: Podgorsak EB Editor, Radiation Oncology Physics: A Handbook for Teachers and Students, Vienna, IAEA publication, 2005, Chapter 16: Radiation Protection and Safety in Radiotherapy; p. 549-607. ISBN 92-0-107304-6.  Back to cited text no. 1
    
2.
Liang W, Guan W, Chen R, Wang W, Li J, Xu K, et al. Cancer patients in SARS-CoV-2 infection: A nationwide analysis in China. Lancet Oncol 2020;21:335-7.  Back to cited text no. 2
    
3.
The Tata Memorial Centre COVID-19 Working Group. The COVID-19 pandemic and the Tata Memorial Centre response. Indian J Cancer 2020;57:123-8.  Back to cited text no. 3
  [Full text]  
4.
Rathod S, Dubey A, Bashir B, Leylek A, Chowdhury A, Koul R,et al. Bracing for impact with new 4R's in the COVID-19 pandemic- a provincial thoracic radiation oncology consensus, Radiother Oncol 2020 (in press).doi: https://doi.org/10.1016/j.radonc. 2020.03.045. [Last accessed on 2020 Apr 11].  Back to cited text no. 4
    
5.
Simcock R, Thomas TV, Mercy CE, Filippi AR, Katz MA, Pereira IJ et al. COVID-19: Global Radiation Oncology's Targeted Response for Pandemic Preparedness. Clin Transl Radiat Oncol 2020 (in press), Doi: https://doi.org/10.1016/j.ctro.2020.03.009. [Last accessed on 2020 April 13].  Back to cited text no. 5
    
6.




 

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