Postal Strike Pushes Radiology Reminders Digital

A natural experiment led to a cut in paper waste, reduced emissions and lowered postage costs without increasing no-show rates

BY MARY HENDERSON April 01, 2026

Ladak

Hanneman

When Canada’s postal service went on strike in late 2024, researchers at the University of Toronto saw a silver lining in the nationwide disruption: an opportunity for a ready-made experiment in reducing greenhouse gas (GHG) emissions and waste in the radiology department.

“Health care and radiology in particular are major contributors to greenhouse gas emissions, and there’s an increasing push not just to understand the scope of the problem, but also to articulate solutions that can be implemented at departmental and institutional levels,” said Aly Muhammad Ladak, a medical student at the University of Toronto and presenter of an RSNA 2025 session on the topic. “Some of the patient communication from the radiology department is still done via mail, which can contribute to paper waste and emissions.”

Collaborating researcher Kate Hanneman, MD, MPH, from the Department of Medical Imaging at the Temerty Faculty of Medicine, University of Toronto and University Health Network in Toronto, said she had previously tried to persuade the radiology departments to switch from mailed appointment letters to digital notifications for MRI exams scheduled 30 days in advance. However, staff were concerned that the change might affect no-show rates.

“One of the traditional barriers to changing patient communication is a fear that it will be ineffective, and patients won’t know about their appointment,” Dr. Hanneman said. “Our staff were concerned both from a health equity and access perspective and from an operational standpoint. No-shows are not good for business.”

With the nationwide postal strike eliminating the ability to send letters, Ladak and Dr. Hanneman saw a golden opportunity to measure the impact of digital versus paper patient communication.

Glass globe in grass climate change concept

Measuring the Footprint of Patient Outreach

To determine the environmental impact of the switch, the researchers quantified paper waste (g), greenhouse gas emissions (GHG) emissions—reported as grams of carbon dioxide equivalent (g CO₂e)—along with appointment no-show rates and costs of MRI appointment reminders during the test and control periods.

CO2e is a metric used to express the total climate impact of all greenhouse gases in terms of the amount of CO2 that would produce the same warming effect.

Before and after the strike, the radiology departments at three hospital systems mailed reminder letters to patients for MRI appointments booked 30 or more days in advance. During the month-long strike from November 15 to December 17, staff pivoted to electronic reminders sent via patient portals and by phone.

Key assumptions, based on published lifecycle assessments for paper production, transportation and telecommunications, included:

GHG emissions per mailed letter:162.4 g CO₂e
GHG emissions per phone call (2 min):7.2 g CO₂e
GHG emissions per patient portal access:1.0 g CO₂e
Paper waste per mailed letter:15.8 g paper waste
Postage cost per letter:$1.24

During 2024, 41,333 outpatient MRI appointments were booked more than 30 days in advance. During the strike period, the 3,970 MRI appointments were communicated to patients via the hospital’s electronic portal, with a confirmatory phone call, while 37,360 appointment letters were sent outside the strike period.

The results were decisive: in addition to the 100% reduction in paper waste, digital appointment scheduling reduced emissions by 95.6% per MRI. Daily postage costs fell by roughly $150, resulting in over $4,500 in savings over the month.

Ladak said that on their own, these numbers may seem modest, but they represent immediately achievable, low‑friction gains that can be scaled across more departments, hospitals and health systems.

“We estimate that the adoption of digital-only communication for outpatient MRI scheduling would reduce annual GHG emissions by 6,414 kg CO₂e, paper waste by 651 kg, and postage cost by $51,253 at our three hospital systems,” Ladak said.

“When we think about feasible interventions in a climate change context, it's often easier to pitch a change if it has co-benefits. Being able to show that it’s good for the environment and can also help the department in an operational or financial sense helps win more buy-in from stakeholders and turn an idea into an intervention.”

— ALY MUHAMMED LADAK

Scaling a Low-Friction Win

If applied nationwide, a switch to digital MRI appointment confirmation could save 26.6 metric tons of paper waste, $2.1 million in postage costs and 262.2 metric tons of CO₂e. These GHG emissions savings are equivalent to 29,504 gallons of gas or 607 barrels of oil.

Importantly, the researchers found no significant difference in no-show rates between the two time periods (1.1% during the strike versus 1.4% during the control period). These demonstrable benefits of digital patient communication and the researchers’ data, which was published in the Canadian Association of Radiologists Journal, helped them make a case for a permanent change at their institutions.

Because the study used administrative scheduling data rather than patient-level records, the researchers couldn’t analyze subgroup impacts.

“When we think about feasible interventions in a climate change context, it's often easier to pitch a change if it has co-benefits,” Ladak said. “Being able to show that it’s good for the environment and can also help the department in an operational or financial sense helps win more buy-in from stakeholders and turn an idea into an intervention.”

Dr. Hanneman said the study data and aligning incentives were critical to enabling the hospitals to bounce forward to a more sustainable way of doing things rather than reverting after the strike.

“Our study highlights how unexpected events can be leveraged to build environmentally sustainable and climate-resilient radiology departments by bouncing forward rather than returning to baseline after a disruption,” she said.

She also emphasized the importance of involving young researchers like Ladak in environmental studies.

“Younger generations are the future of radiology, and we need to engage our medical students and other trainees in sustainability efforts across the board,” Dr. Hanneman said. “I am so encouraged to see so many wonderful medical students like Aly actively participating in these initiatives.”