If a volcano in a distant country erupts, will cancer screenings in Japan stop!? The unknown 'weak point of medicine'

A volcano erupted overseas! Does it actually affect Japan too?

On June 17, 2025, Mount Lewotobi on Flores Island, Indonesia, erupted violently.
Actually, this volcano also had a major eruption in November 2024. So, we need to keep paying attention, but...

Of course, the most important thing is wishing for the safety of the local people.
But this eruption might also affect our own 'lifelines' living in Japan.

Believe it or not, there is a possibility that medical tests taken by over 1,000 people every day could stop for days, or perhaps even months.

What kind of tests would stop?

In Japan, a test called 'SPECT (Single-photon emission computed tomography)' is often used to check for bone metastasis of cancer and to monitor brain and heart function.
What is needed for that test is a radioactive isotope called Technetium-99m... 'Isotope' sounds unfamiliar, right? You can just think of it as an 'element'!

Technetium is the first element humanity intentionally created artificially, and it barely exists in the natural world. As the name suggests, it was obviously named after 'technology'.

This radionuclide is like an element that exists for the sake of medical testing, and it is an excellent tool that

• can reveal heart and brain function when carried in the bloodstream

• can detect bone metastasis of cancer when made to behave like calcium

.

Let's look at how Technetium is used in more detail!

The pattern of carrying it in the bloodstream

If you look at blood flow in the heart, you can detect heart disease.
If you look at blood flow in the brain, you can identify areas that aren't working properly, which is useful for diagnosing dementia and checking its progression.

The pattern of making it behave like calcium

When cancer metastasizes to the bone, it can create unnecessary bone and cause severe pain.
At this time, by using the property that cancer takes in Technetium along with calcium, you can find where the metastasis is.

Because it has such a wide range of uses, about 1,000 patients in Japan undergo this test every day.

The critical weakness of Technetium...

But... Technetium-99m is a radioactive substance.
As written above, it barely exists in the natural world.
Moreover, it only has a half-life of 6 hours... which means the amount is halved after 6 hours... and halved again after another 6 hours... it just keeps decreasing.

Let's put it in the refrigerator!... No, that's useless. There's no way to store it...

That is why Technetium-99m must be extracted at the hospital right before it is used on a patient.

To do that, you need a 'parent' radioactive substance called 'Molybdenum-99'. This naturally produces Technetium-99m roughly every 24 hours, so it is called the parent nuclide of Technetium-99m.

The Technetium-99m that is born is called the 'daughter nuclide'. I wonder why it isn't called a son nuclide or child nuclide. Oh well, never mind.

However, this Molybdenum-99 is also radioactive, so it naturally has a half-life. That half-life is just under three days. Moreover, since it is produced in special nuclear reactors, it cannot be made in Japan.

So, in the end,if we don't import Molybdenum-99 from overseas every week, we can't get Technetium-99mis the situation.

Molybdenum-99 cannot be sent by sea!

Yes, it is too slow!
It takes months for sea freight to reach Japan, so by the time it arrives, the amount has decreased and it is completely empty. It becomes useless.

That means... we have no choice but to send it by airplane.

But!

We are transporting large quantities of radioactive material. It is not just a matter of flying it; flight paths and procedures are strictly determined, and they cannot be changed easily.

If thatflight path were to be cut off due to the influence of a volcano or something... it's game over...

After just one week, the Molybdenum-99 in the country decreases according to its half-life and disappears... and Technetium-99m can no longer be made...

Yes, without Molybdenum-99, Technetium-99 is not born.
In the end, it becomes impossible to perform the examinations.

This nightmare... actually happened!

Everything I have stated so far is not just a prediction.

Around 2010,a story that actually happened.

At that time, Japan was mainly importing from Canada, but the nuclear reactor that was producing it had its regular inspections prolonged due to aging, and it was decided that Molybdenum-99 would not be available for a while.

So, we had just managed to set up a system to import it from South Africa with great difficulty. The route was via Europe.

In the midst of that, a massive volcanic eruption occurred in Iceland in April 2010.

Aircraft are very vulnerable to volcanic ash.
If they fly through volcanic smoke, they will break down to a level where they can never be repaired.
Of course, airlines canceled flights near Europe one after another.

Of course, that includes the airplanes that were supposed to transport Molybdenum-99 to Japan.

Following Canada, we were no longer able to obtain it from South Africa either...

The impact did not stop there. Even after the production reactors for Molybdenum-99 began to restart, Molybdenum-99 did not easily reach Japan.

Do you know why?

At the time, the words of an American acquaintance left a strong impression on me.

Yes... human life is precious regardless of race.

Confronted with this fact, I
'Please give Japan Molybdenum-99 anyway'
could not say that.

Japan, which is far away from anywhere in the world

On the world map we usually look at, Japan is drawn in the center, but from Europe, from America, from Canada, from South Africa...it is incredibly far away.

At the time, I was on a team developing new technology to produce Molybdenum-99 domestically. I remember we were desperate to break away from our dependence on imports and worked feverishly on research, convinced that domestic production was the only way.

What is the current situation?

Now, more than 10 years later. Although methods using low-enriched uranium and methods using accelerators instead of nuclear reactors have been proposed, and research and development are progressing, it cannot be said that things have improved much.

The world is still completely dependent on a limited number of production reactors.

I also proposed a method that could cover more than half of the world's demand using a nuclear fusion reactor, but... well, it wasn't selected for competitive funding, and above all, I left academia.

What I can do now

Even so, I have the means to 'convey' information.
That is why I am aiming to be a science writer and writing articles on note.

If it stays in your heart even a little, like 'Oh, I remember reading about that,' that is enough.
If more people become interested, research will move forward, and enthusiasm will connect.

Even now, I believe that the only way to solve this situation is through domestic production of Molybdenum-99.

Even now that I have left academia, I continue to pay attention to and support research developing technology to manufacture radiopharmaceuticals.

Because what they are supporting might be my future life, and yours.

Reference: Nature magazine 'Medical isotope shortage reaches crisis level' (2009)

Acknowledgments

I decided to write this article because of the article Hikarun shared with me! Thank you! Here is the article! It explains in detail why airplanes are vulnerable to volcanoes, so I recommend it!
https://note.com/hikarun2022/n/n3b23e41c6e44