Cutting-edge advancements in radiation therapy (RT) may allow oncology practitioners to only target the current tumor and avoid damaging healthy tissue. During a session on April 29, 2021, at the ONS 46th Annual Congress, W. Neil Duggar, PhD, DABR, of the University of Mississippi Medical Center, provided an overview of RT from a medical physics perspective, with a focus on how developing technologies may revolutionize care for patients with cancer.

Don’t Get Stuck in the Past

“Unfortunately, as in many fields, there are radiation clinics that take shortcuts in the name of their bottom line, and the patients absorb the cost when radiation is either more toxic or less effective than it should be,” Duggar said.

For example, some clinics still practice outdated techniques. An important development to be aware of is in 3D imaging, which “should be employed in every area of RT except perhaps in skin treatments. Avoiding this in head and neck cancer, for example, will most likely lead to inadequate radiation dose to portions of cancerous tissue,” Duggar said. “In breast cancer, hotspots can only be properly addressed with treatment planning on imaging, as well as management of radiation heart dose, which can lead to long-term cardiac issues if not addressed.”

Intensity-modulated radiation therapy (IMRT) is another important consideration. “IMRT has been demonstrated as an excellent tool to escalate tumor dose and minimize toxicity,” Duggar said. However, “it is not always indicated for every type of cancer and must be chosen based on professional guidelines or clinical goals.”

Oncology Treatment in a FLASH

Of the radiation technologies in development, FLASH-RT, is a “big deal” for patients with cancer, Duggar said. FLASH-RT uses standard radiation, just delivered at ultra-high dose rates. The resulting FLASH effect produces higher tumor death with less damage to normal tissue using the same radiation dose.

“The most exciting implications for FLASH-RT are that it seems to be an emerging option for patients who previously had none,” Duggar said. “With modern cancer care, patients are living longer and often end up needing additional radiation, which can be very difficult to provide because normal tissue has a radiation memory and cannot handle retreatment to the same extent as initial radiation.”

“FLASH-RT may be the answer we have sought for some of these patients to whom radiation practitioners have previously been able to offer very little hope,” Duggar said. “Of course, FLASH-RT also opens the door to offer higher tumor dose and perhaps some ability to treat hard-to-reach tumors such as near the brainstem or spinal cord, for which previous efforts have had to be somewhat reserved.”

Artificial Intelligence and the Future of Radiation Treatment

Duggar concluded by discussing how potential advancements provided by machine learning and artificial intelligence in RT “appear to be endless. The realm is a huge opportunity for creativity to solve problems in new ways. Our work makes use of the fact that each computed tomography image (or other modality) has information that is simply beyond the human eye.

“We are in the process of building an algorithm that can provide interpretable decision support that will feel hopefully less like a black box and more like an assistant guiding the radiologist on important areas to pay attention to. We have some initial results that indicate potential accuracy results above 95%, but our data is very preliminary at this point,” Duggar said.