Particle accelerator

• Ionizing radiation, or the emission of high-energy waves or particles, works as a therapy by damaging a cancer cell’s DNA.
• It’s an effective tool for killing cancer cells because they are generally much less adept at DNA repair compared to healthy cells.
• Damaging specific parts of DNA prevents cancer cells from reproducing, effectively killing them.

Fundamentals of radiation therapy

• At the heart of radiation therapy lies the fundamental principle that cancer cells are more susceptible to radiation than healthy cells.
• Sometimes resistance to radiation in cancer cells may be comparable or even greater than that of their neighboring cells.
• When tumors lie close to vital organs that are highly sensitive to radiation, such as the brain or the bowels, it significantly limits the amount of radiation that can be delivered.

External beam radiation therapy

• External beam radiation involves directing radiation from an outside source to a single part of the body.
• Another form of radiotherapy is proton beam therapy, or PBT, which directs protons instead of X-rays at tumors.

Image-guided radiation therapy

• By acting as the eyes of the care team, imaging reduced uncertainty about the location of tumors and improved the precision and accuracy of radiation therapy.
• Newer linear accelerators are now incorporating MRIs, which significantly improve visualization of patient anatomy and tumors, further advancing treatment precision and accuracy.

Researchers are also adding positron emission tomography, or PET, scanners that provide information about the metabolic function of tumors. This advance makes it possible to increase the radiation dose specifically at the most active areas of tumors.

Adaptive therapy

• An emerging approach to radiation therapy called adaptive therapy uses imaging to dynamically adjust treatment as the tumor or its positioning changes each day.
• However, adaptive therapy may apply several adjustments or lead to a completely new treatment plan in order to address changes to the tumor’s condition over the course of treatment.
• The fact that the process needs to be repeated multiple times renders adaptive therapy particularly resource-intensive and time-consuming.

Brachytherapy

• Brachytherapy – stemming from the Greek word “brachys,” meaning “short” – is another widely used method in radiation therapy.
• In contrast to external beam radiation therapy, where radiation often must pass through healthy tissue to reach cancer cells, brachytherapy applies radiation directly to the tumor.

• The conventional approach to brachytherapy involved using needles to place or inject radioactive seeds inside or adjacent to the cancerous tissue.
• An increasingly popular form of brachytherapy called high-dose rate brachytherapy involves using a tube to guide a more highly radioactive seed directly to the affected tissue before removing it after a few minutes.

Future of radiation therapy

• Researchers are also exploring treatments using ions heavier than protons to more effectively damage DNA in cancer cells and enhance the efficacy of radiation therapy.
• Advances in the field hint at a future of more personalized radiation therapy, highlighting the fusion of technology and medical expertise in the fight against cancer.

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.