Carbon-ion radiotherapy is a most advanced radiotherapy.
Main treatment methods for cancer
Multidisciplinary approach with surgery, chemotherapy and radiotherapy is taken for cancer treatment. The use of carbon-ion beam is the state-of-art technology of particle radiotherapy while photon beam is widely used for conventional radiotherapy.
Comparison of cancer therapies
Carbon-ions are accelerated up to 70% of the light speed and irradiated into deeply seated tumors.
What is carbon-ion?
The charged particles heavier than helium is called a "heavy-ion". Carbon-ion has been clinically available for cancer therapy to date. The weight of carbon-ion is 12 times heavier than proton.
Features of Carbon-ion Radiotherapy
Precise irradiation of deeply seated tumor
One of the fundamental physical features of carbon-ion beams is delivering relatively low dose en route to the target and releasing the greatest energy around the end of beam range. This characteristic is called "Bragg curve", and the point of maximum energy deposition is called "Bragg peak". The technical strategy of carbon-ion radiotherapy is to adjust the position and shape of the Bragg peak to the region of tumor in three dimensionally. As a result, the dose can be concentrated on the target while suppressing the dose of surrounding normal tissues.
Strong power of killing cancer cells
The power of carbon-ion radiotherapy to kill cancer cells is much stronger than photon and proton beams.
Compared to photon beams and proton beams, carbon-ion radiotherapy is highly capable of killing cancer cells. It is therefore more effective on tumors which is resistant to conventional photon/proton radiotherapy.
Shorter period of treatment
Prostate cancer needs to be irradiated about 40 fractions with intensity modulated radiation therapy (IMRT), but carbon-ion radiotherapy requires 12 fractions of irradiation.
Only a single irradiation with carbon-ion beam is designed for the treatment of stage I lung cancer even though the stereotactic radiotherapy (SRT) requires 4 to 6 fractions.
* Shorter period of time means for the comparison between carbon-ion and conventional radiotherapy.
* The number of irradiations is based on the treatment plan at the National Institute of Radiological Sciences.
A Case Treated by Carbon-ion Radiotherapy
Lung cancer(after one time of irradiation with carbon-ion beam)
This patient had early lung cancer in the right lung. The shadow of lung cancer disappeared after single irradiation of carbon-ion beams.
* Image source: National Institute of Radiological Sciences (NIRS)