Sumitomo Heavy Industries Ltd.
Sumitomo Heavy Industries Ltd.
10/29/2024 | Press release | Distributed by Public on 10/28/2024 23:05
Sumitomo Heavy Industries and Osaka University Graduate School of Medicine become the First to Observe the Cytoprotective Effects of Proton FLASH Irradiation at the Cell Test Level
Kenzo Sasai, Senior Engineer at Sumitomo Heavy Industries, Ltd. (Head Office: Shinagawa-ku, Tokyo; Representative Director, President, and CEO: Shinji Shimomura; hereinafter "SHI"), Professor Kazuhiko Ogawa of Department of Radiation Oncology, Osaka University Graduate School of Medicine, and their research group (hereinafter the "Research Group") have successfully observed for the first time in the world that "cell survival rates increase with ultra-short, high-dose proton beam irradiation."
Until now, no increases in cell survival rates from ultra-short-time proton beam irradiation (referred to as "proton FLASH irradiation") had ever been reported, regardless of the oxygen concentration. Similarly, no increases in cell survival rates from proton FLASH irradiation under normal oxygen concentration conditions had ever been observed.
The Research Group demonstrated that cell survival rates increase with ultra-short irradiation under normal oxygen concentration conditions by using SHI's newly developed superconducting cyclotron accelerator for proton beam therapy to deliver high doses for very short periods. It is expected that this result will lead to the utilization of proton FLASH irradiation in proton cancer therapy with fewer side effects.
Background
Proton beam therapy, a type of radiation therapy, has a property called the "Bragg peak," in which the proton beam acts most strongly at a specific depth in the body and has little effect beyond that depth. This property allows high doses of proton beams to be focused on tumors located deep inside the body, bringing considerable attention to proton beam therapy as a radiation treatment for cancer.
In some cases, efforts to reduce dose and damage to healthy tissues near the tumor make it necessary to compromise the dose delivered to the tumor or even result in doctors having to abandon proton beam therapy altogether. Accordingly, ways of further reducing dose to normal tissues must be developed to expand the clinical utility of proton beam therapy.
In recent years, it has been reported in radiotherapy that irradiating tumors with high doses for ultra-short periods produces protective effects that maintain treatment effectiveness against the tumor while controlling damage to normal tissues. The technique is called "FLASH irradiation" because the radiation is delivered instantaneously. It is attracting a great deal of attention worldwide. The most typical protective effect observed in cell experiments is an increase in cell survival rates.
Until now, no increases in cell survival rates had ever been reported for ultra-short proton irradiation, regardless of the oxygen concentration. Likewise, no increases in cell survival rates had been observed for ultra-short proton irradiation under normal oxygen concentration conditions. Experimental environments for ultra-short, high-dose proton irradiation are not well developed, particularly in Japan; consequently, no attempts to deliver doses higher than certain levels had been made in Japan.
Demonstration Details
The Research Group conducted its tests using a superconducting AVF cyclotron accelerator and next-generation proton therapy system test facility developed by SHI and installed at the Saijo Application Development Center. Irradiating cells with the ultra-short period, high-dose proton beams made possible by this equipment, the group became the first in the world to observe increases in the survival rates of cells exposed to proton beams after ultra-short duration irradiation under normal oxygen concentration conditions.
The ultra-high dose rate beam was developed, prepared, and delivered by an SHI team, while the physical evaluation of the irradiated area and cell assessment were performed by a Group from Department of Radiation Oncology, Osaka University Graduate School of Medicine. Resulting observations showed that the survival rate increased in the cell groups used in the study at a dose rate of 250 Gy/s and a dose of 20 Gy or higher.
Social Significance
The study's results will enhance our understanding of how proton FLASH irradiation induces protective effects and should pave the way for its future application in cancer treatment with fewer side effects. Proton FLASH irradiation combines the physical properties of proton beams-namely, the capability to deliver high dose concentrations to tumors-with biological properties of the protective effect that reduce damage to normal tissues. This combination is expected to have a greater therapeutic effect on cancer and reduce side effects.
The results described here were published in the English-language scientific journal Anticancer Research on October 1, 2024.
Until now, no increases in cell survival rates from ultra-short-time proton beam irradiation (referred to as "proton FLASH irradiation") had ever been reported, regardless of the oxygen concentration. Similarly, no increases in cell survival rates from proton FLASH irradiation under normal oxygen concentration conditions had ever been observed.
The Research Group demonstrated that cell survival rates increase with ultra-short irradiation under normal oxygen concentration conditions by using SHI's newly developed superconducting cyclotron accelerator for proton beam therapy to deliver high doses for very short periods. It is expected that this result will lead to the utilization of proton FLASH irradiation in proton cancer therapy with fewer side effects.
Background
Proton beam therapy, a type of radiation therapy, has a property called the "Bragg peak," in which the proton beam acts most strongly at a specific depth in the body and has little effect beyond that depth. This property allows high doses of proton beams to be focused on tumors located deep inside the body, bringing considerable attention to proton beam therapy as a radiation treatment for cancer.
In some cases, efforts to reduce dose and damage to healthy tissues near the tumor make it necessary to compromise the dose delivered to the tumor or even result in doctors having to abandon proton beam therapy altogether. Accordingly, ways of further reducing dose to normal tissues must be developed to expand the clinical utility of proton beam therapy.
In recent years, it has been reported in radiotherapy that irradiating tumors with high doses for ultra-short periods produces protective effects that maintain treatment effectiveness against the tumor while controlling damage to normal tissues. The technique is called "FLASH irradiation" because the radiation is delivered instantaneously. It is attracting a great deal of attention worldwide. The most typical protective effect observed in cell experiments is an increase in cell survival rates.
Until now, no increases in cell survival rates had ever been reported for ultra-short proton irradiation, regardless of the oxygen concentration. Likewise, no increases in cell survival rates had been observed for ultra-short proton irradiation under normal oxygen concentration conditions. Experimental environments for ultra-short, high-dose proton irradiation are not well developed, particularly in Japan; consequently, no attempts to deliver doses higher than certain levels had been made in Japan.
Demonstration Details
The Research Group conducted its tests using a superconducting AVF cyclotron accelerator and next-generation proton therapy system test facility developed by SHI and installed at the Saijo Application Development Center. Irradiating cells with the ultra-short period, high-dose proton beams made possible by this equipment, the group became the first in the world to observe increases in the survival rates of cells exposed to proton beams after ultra-short duration irradiation under normal oxygen concentration conditions.
The ultra-high dose rate beam was developed, prepared, and delivered by an SHI team, while the physical evaluation of the irradiated area and cell assessment were performed by a Group from Department of Radiation Oncology, Osaka University Graduate School of Medicine. Resulting observations showed that the survival rate increased in the cell groups used in the study at a dose rate of 250 Gy/s and a dose of 20 Gy or higher.
Social Significance
The study's results will enhance our understanding of how proton FLASH irradiation induces protective effects and should pave the way for its future application in cancer treatment with fewer side effects. Proton FLASH irradiation combines the physical properties of proton beams-namely, the capability to deliver high dose concentrations to tumors-with biological properties of the protective effect that reduce damage to normal tissues. This combination is expected to have a greater therapeutic effect on cancer and reduce side effects.
The results described here were published in the English-language scientific journal Anticancer Research on October 1, 2024.