Shielding radiation with the fresh idea of using a removable lead shield
Radiation therapy is roughly divided into two forms of treatment: “external radiation therapy” and “interstitial radiation therapy.” With external radiation, the radiation penetrates into the body to destroy the cancer. On the other hand, interstitial radiation therapy uses a radioactive source positioned directly into the tumor, minimizing radiation to the surrounding healthy tissue.
However, in the case of tongue cancer, some patients develop osteoradionecrosis, or bone death, after radiation therapy because there are gum tissue and jaw bones near the tongue. Dr. Murakami says, “To protect patients from unnecessary radiation, various methods, such as putting resin between the tongue and the gums, were attempted; however, it was impossible to completely shield radiation. Having said that, if lead, which can completely block radiation, is used instead of resin, CT images cannot be taken, which makes it difficult for us to plan treatments.”
So, Dr. Murakami developed a resin mouthpiece-type device (modular spacer) with grooves designed to allow the removal of a lead shield. In treatment, 3D CT images of a patient with a resin modular spacer formed to the arch of the patient are taken. Next, the lead shield is inserted into its grooves and radiation is sent. “26 patients have been treated with this device as of February 2017, but side effects have not been seen in them.” “Although it looks like a simple device, in reality, it took me more than a decade to come up with this idea.” he added.
This achievement, posted in the online edition of the US science journal PLOS ONE in May 2016, received a lot of media attention, attracting many patients from both in Japan and abroad to Osaka University Dental Hospital.
Toward an era in which safe radiation therapy is an option
Although the validity of this device based on the Dr. Murakami’s idea is widely accepted, he has not applied for a patent for the device. On the contrary, the construction method of the modular spacer is described in papers. About the reason for this, he said “I want to encourage many doctors to use this device freely and I want many patients to choose radiation therapy that can be utilized in their treatment without losing a large portion of their tongue.”
What has driven him this far? “Harsh words from one of my tongue cancer patients,” he said. That patient’s tongue cancer was cured with radiation treatment, but later, side effects appeared. His lower jaw bone necrotized, so half of his jaw needed to be removed. The patient, whose face underwent a drastic change, said, ‘I take back the “Thank you” I said before.’ I still cannot forget those words.”
From these experiences, “I recommend this treatment after asking myself “Would I recommend this treatment if this patient was my family member?” he said. He continued by saying, “My greatest pleasure comes from when I see patients who have been completely cured and they look healthy and happy. I will continue to do my best in research and treatment so that I can see the smiling faces of many people who chose radiation therapy."