HOME > Med in Japan Newsletter No.1 July 2012 > The World Leader in Radiotherapy for Solid Cancers

The World Leader in Radiotherapy for Solid Cancers



National Institute of Radiological Sciences (NIRS) constructed the first original machine in the world specialized for heavy ion radiotherapy named HIMAC (Heavy Ion Medical Accelerator in Chiba). HIMAC has achieved remarkable results in clinical trials and advanced medicine.

What Is the Radiotherapy?

Radiotherapy = cure without surgery: neither painful, hot, nor scary, and no traces left.

Radiotherapy is not a treatment by killing cells with the heat generated by radiation, but a sophisticated method of killing cancer cells with radiation, by making microscopic cuts within the molecules of DNA (deoxyribonucleic acid) in a cell nucleus, and of preventing further cell division.

Cancer, the First Cause of Death

The ultimate solution for treatment is radiotherapy. The numbers of patients with cancer, and of deaths resulting from cancer are increasing recently. In 2006, the number of people who died of cancer in Japan amounted to 330,000, which is 33% of the total deaths of the year.

Carbon Ion Beam : Physical and Biological Features

Advantages of Carbon Ion Radiotherapy:

- Cure for intractable cancers, short-term treatment, high quality of life

- Curing cancers not curable by surgery nor conventional radiation

As you can see in the figure, X-rays are not suitable for the treatment of cancers located in a deep region of the body because their effect is gradually decreasing with depth. In comparison, heavy ions are suitable for the treatment of these cancers because they affect cells only weakly until they reach the tumor, and demonstrate an enormous effect at the moment they stop in the tumor.

What is a heavy ion beam?*

heavy ion beam: beam of such ions as carbon(C), neon(Ne), silicon(Si) or argon(Ar), etc. , flying at extraordinarily high speed. NIRS is using a heavy ion (carbon ion) beam for cancer treatment.  

Other radiations*

proton beam: beam of protons (nuclei of hydrogen) flying at an extraordinarily high speed.

photon beam: a beam of photons, particles of light . They fly at the speed of light. X-rays and gammarays are photon beams at high energy.

*When these ions are used for the treatment, an extremely large number of flying particles is made up to a bundle (beam) with the same direction for irradiating the tumor. size of particles

Physical features of a carbon ion beam

The depth where the ion stops is exactly predetermined. The effect becomes enormous only when the ion stops.

Biological features of a carbon ion beam

The effect is stronger than X-rays for the same dose.

Difference between X-ray and carbon ion beam treatments

Applicable Cases and Clinical Results

What cases the carbon ion radiotherapy can be applied at NIRS?

Applicable Cases

[Cases Advanced Medicine is applicable]

  • head and neck cancers / nose, paranasal sinus, salivary gland : 4-week treatment
  • lung cancers (non-small-cell cancers) / local advanced cancer : 3 to 4-week treatment
  • liver cancers : within 1 week treatment
  • prostate cancer : 4 to 5 week treatment
  • bone and soft tissue sarcoma / surgery not applicable cases : 4 week treatment
  • malignant melanoma (choroid*) : 1 week treatment (*eye)

[Cases Clinical Triall still applicable]

  •  lung cancers (non-small-cell-cancers) : stage I 1 week treatment
  • uterine cancers, brain tumors, pancreas cancer
  • esophageal cancer
  • liver metastasis of colon cancer etc.

What data prove this therapy is really effective from your clinical results?

The rate the size of tumor reduces or its growth stops by treatment, is called the local control rate, an index for the effectiveness of treatment. Our carbon ion radiotherapy obtained fairly high values of the 3-year local control rate; more than 90% for non-small-cell lung cancers, 80%~90% for liver cancers, and almost 100% for prostate cancer, for example. We can therefore conclude that the carbon ion radiotherapy is reasonably effective.

Medical Cost

How much is the patient's expense in the system of the "Advanced Medicine"?Hospitalization is necessary for our carbon ion radiotherapy. The expense for treatment in this system is 3,140,000 yen.

Download the NIRS pamphlet for more information:


(click to download)


Med in Japan Newsletter No.1 July 2012