The Environmental Impact of Radiation Oncology: The "Footprint" of External Beam Radiation Therapy

PURPOSE/OBJECTIVE(S)

There is a growing concern for the healthcare sector's impact on the environment. Prior carbon impact studies in radiation oncology have been limited in scope and methodology. This study aims to fill this gap by using an internationally recognized cradle-to-grave life cycle assessment (LCA) approach to quantify all environmental impacts from raw material extraction to product disposal for external beam radiation therapy (EBRT) in treating the most commonly diagnosed cancers.

MATERIALS/METHODS

This LCA was performed in accordance with ISO 14040 and 14044 at a single academic medical center. It quantified the environmental impact of EBRT across four categories: global warming potential (GWP), carcinogenic and non-carcinogenic human toxicity, and respiratory effects (PM2.5), from initial consultation to the completion of the last EBRT fraction for each disease site. Data collection involved weighing all materials used, measuring/calculating building and equipment electricity usage (e.g., HVAC and Linacs), and recording patient and staff transit. The study analyzed the impact of both minimum and maximum fractionations for each disease site and simulated alternative clinical scenarios such as telemedicine, renewable energy use and hypofractionation.

RESULTS

Regardless of disease site, there were significant differences in the environmental impacts associated with transit, electricity and supplies for EBRT treatment cycles. Staff and patient transport contributed the most, accounting for >92% of the total environmental impact including GWP (5.02x102 ± 9.38x101 kgCO2eq), carcinogenic (6.25x10-5 ± 1.23x10-5 CTUh) and non-carcinogenic human toxicity (1.16x10-4 ± 2.35x10-5 CTUh). Electricity accounted for 1-13% of the total impact, with most impact arising from respiratory effects (3.05x10-2 kg ± 2.72x10-3 PM2.5). The impact of supplies and materials was less than 3% across all categories. Alternative scenario modeling showed that telemedicine had a maximum impact reduction of 3.5% (2.54x 101kgCO2eq) for GWP, while renewable energy use had a maximum impact reduction of 8% (2.37 x 10-2 PM2.5) for respiratory effects. Reducing the number of total treatment days via hypofractionation can reduce GWP by 67-78% and carcinogenic emissions by 63-77% (3.48 x 102 - 5.53 x 102 kgCO2eq) and (3.73 x 10-5 - 6.85 x 10-5CTUh), respectively, with variation depending on the total number of fractions.

CONCLUSION

This study provides a comprehensive environmental impact assessment for EBRT among the most commonly treated disease sites, establishing a baseline metric and identifying targets for impact reduction. We are currently performing a multi-center validation study to be completed by June 2023. Our findings fill an important gap in cancer care and are critical for developing sustainable practices in the face of increasing demand for radiotherapy in a changing climate. LCAs evaluating all aspects of cancer care will be essential for promoting equitable and sustainable care.

Recovery of Cellulase by HPMC-Salt Precipitation: Analysis by Statistical Experimental Design

Production of industrial enzymes including cellulases requires minimum cost with the downstream processing. The objective of this work was to analyze the precipitation of cellulases by ammonium sulfate in the presence of hydroxypropyl(methylcellulose) as a co-precipitant through the use of statistical experimental design. The model generated with the experimental results showed that high protein recovery can be achieved at high levels of temperature, aging times, and rate of salt-solution addition, and at a low mixing level. The results also allowed the observation that activity recovery was improved at high levels of temperature, rate of salt addition and mixing level, and a low level of aging time.