A new way of concentrating radiotherapy dose in tumors, while minimizing damage to healthy cells, has been proposed in research led by scientists at the University of Strathclyde.
The study proposes that focusing high-energy particle beams on a small spot deep inside the body could potentially enable clinicians to target cancerous tumors precisely, while reducing the dose to surrounding tissue.
External beam radiotherapy involves treating patients with either high energy X-rays or particle beams. tumor cells are killed by the radiation, which is usually administered in multiple fractions, which are applied daily over several weeks. The main goal is to kill tumor cells using beams of radiation while minimizing damage to Healthy cellsThe study has been published in Scientific Reports.
Professor Dino Jaroszynski, who leads the project, said: “Around half of the population will suffer from cancer at some time in their lives. Of these people, half will be treated using radiotherapy or a combination of radiotherapy and chemotherapy.
“One of the challenges in radiotherapy is to deposit a high radiation dose in a way that the dose fully ‘conforms’ to the tumor, to ensure that all cancerous cells are killed, while preventing damage to healthy cells. Our study shows that we can very simply focus radiation onto a tumor to irradiate it while reducing the dose in surrounding healthy tissue.
“In a similar way to a magnifying glass focusing the sun’s rays to a small spot, we propose to focus a particle beam to a small spot using a magnetic lens to ablate the tumor.”
Common forms of radiation currently used in radiotherapy include X-rays produced by electron beams from ‘medical’ linear accelerators, or linacs, that generate a type of radiation known as bremsstrahlung X-rays, which then target the tumor.
These relatively low energy electron beams from the linac can also be used directly to irradiate tumors but they do not penetrate deeply into the body and therefore are not commonly used.
One of the disadvantages of using X-rays in radiotherapy is that they are absorbed in the body and their effects diminish, resulting in a high entrance dose. Proximal and distal doses—before and after the tumor—can also be as high as, or higher than, the radiation dose in the tumor.