This is an English translation of @team_nakagawa statement in Japanese taken from here. Download PDF File.

We are the doctors, and other experts of nuclear technology, theoretical physics, and medical physics in radiation oncology group at The University of Tokyo Hospital. Our team has been organized to share the knowledge of medicine regarding the accident in Fukushima of nuclear power plants.

I am Keiichi Nakagawa, who is a director in radiation oncology at The University of Tokyo Hospital. I express deeply sympathy for the stricken people in Tohoku and Kanto massive earthquake area. I‘d like to make a tweet on current leak at Fukushima nuclear power plants.

March 15
Radiation itself is a light (a photon) or a particle which has an energy allowing to go through materials. If we receive it too much, it causes substantial damages on body and its gene. We call an ability to emit a radiation “radioactivity”, and call a material embedded radioactivity “a radioactive material”. Under current accident of nuclear plants, radioactive materials leaked out. It looks like pollen flies spread in the air. The difference is that this material has the radioactivity.
Suppose what is effective to prevent pollen from coming into your house.

First is to flap away it from your clothes before inside your house. To shut the windows to seal is also effective. In contract to pollen, of course, a radiation can go through walls and windows; therefore there is no way to prevent all radiations coming into basically. We can easily understand that in case if you breathe radioactive materials into you body, it would make a serious situation.

We call an exposure receiving inside body “internal exposure”. It is more dangerous than “external exposure” which comes from outside body. The main reason is that we can wash out those materials outside body while we cannot do it in case inside body. Just like pollen, when you go home with much amount of radioactive materials, it is important to flap away them from your clothes and wash your body.

There was an opinion that closing the window is not useful. This opinion is totally misunderstanding. Closing the windows is greatly effective. If there are something to prevent, radioactive materials cannot come in, and also the radiation reduces before it reaches in your body.

In the first place, the debate of whether there will be radiation exposure or not is meaningless because we are all “exposed to radiation” just by living in this world. At the world average, we are exposed to 2.4mSv (millisievert) of radiation a year.

(Radiation emitted from atmosphere, ground, space, food and so on is called natural radiation.)

“mSv” reads “millisievert.” “Millisievert” is a unit to measure an impact radiation has on human body. “Milli (m)” is 1,000 times greater than “micro(µ), so 1mSv = 1,000µSv.

Natural radiation exposure varies among countries and regions. For example, at Ramsar, Iran, people are exposed to 10.2mSv a year. That is 10,200µSv. There are also areas around the world with low exposure.

March 16
Yesterday (March 15, 2011), in Tokyo, radiation dose of approximately 1µSv per hour (1µSv/h) was observed. How does this compare to the natural radiation we receive from atmosphere, food and so on ? If you stay in Tokyo with this situation for 100 days, you receive 2.4mSv = 2400µSv. In other words, one would be exposed to the dose three times greater than normal level. Now, how much medical impact does such a radiation dose have?

The lowest radiation level that is detectable clinically is said to be 200mSv(millisievert), i.e. 200,000µSv(microsievert). Symptoms start to appear at 1,000mSv, or 1,000,000µSv(microsievert).

As an extreme example, the probability that one would die within 60 days is 50 % if one is exposed to 4,000,000µSv (microsievert).

At lower radiation doses, there is no symptom and abnormal finding is negative, but the risk of one’s developing a cancer does increase except for when the accumulated dose is less than 100mSv (millisievert) . In such a case, the risk of having a cancer does not
increase. And even when the risk increases, the increment is about 0.5% at the accumulation of 100mSv.

The leading cause of death in Japan is the cancer, whose ratio is the No.1 in the world. One of two people gets afflicted by a cancer. That means the risk of getting a cancer, normally 50 %, becomes 50.5% if one is exposed to 100mSv of radiation.

Smoking is more dangerous. If the current level of 1µSv per hour continues, the accumulated radiation reaches 100mSv in 11.4 years and you realize how little the risk is.

Now, if we compare amount of radiation to hot water in a bathtub, “x millisievert per hour” would mean “how strongly the hot water flows out from the faucet.” The higher the value, the more intensely the water is gushing out. And the amount of water accumulated in the tub is expressed as “x millisievert.”

To continue the same metaphor, it is like 100 mV (millisievert) of hot water accumulated drop by drop over 11.4 years. Note that the same amount of hot water that gushed out in just a few minutes and that accumulated slowly over 11 years, in case of radiation, have very different levels of impact on a human body. DNA of any living thing starts to repair immediately even if it is damaged by radiation.

And if the “dose rate” is 1µSv/h (micro sievert per hour), damaged DNA would repair mostly, and therefore it has little medical impact. Of course, that does not mean we can say there will be absolutely no impact in the future.

Answer to questions
(1) If you are pregnant, please note that the fetus in the first four months of pregnancy is most affected by radiation. It has been shown that accumulation of less than 100mSv(millisievert) does not have impact on fetus after that period. Data on radiation protection for pregnant women are compiled by the International Commission on
Radiological Protection.

(2) The impact of radiation on a human body is equal for both external and internal exposure, and yet, internal exposure can be said to be more dangerous because once radioactive materials are in your body, you cannot escape the exposure. But, even if a radioactive material is taken in a human body, the impact of its radiation decreases while the material is excreted from the body and the radioactivity decreases naturally.

(3) You probably heard of iodine and cesium as radioactive substances which can be scattered from a nuclear power plant. The time required for those substances to be absorbed in and excreted from a human body is different depending on the form of the substance and the part of the body the substance is taken in. At The University of Tokyo Hospital, we use radioactive iodine to treat cancer in thyroid cancer. When we use this therapy, patients’ intake of iodine is controlled so that radioactive iodine would accumulate in their thyroid. (We will take up this topic some other time.) As a rule of thumb, once iodine is taken in our body, it takes about 30 days for a half of it to be excreted from our body, but the iodine radioactivity itself also decreases by half in 8 days. Most of radioactive iodine emits radiation until they leave your body. Note, however, that if it is not taken in the thyroid, most of it will leave your body within a day.

Photo from news.com.au

Updates:

Updated March 18 Beware of online scams. Two Koreans were caught running an online fundraising campaign for quake-stricken Japan with a bank account falsely named as one acknowledged by the Japanese Red Cross, police said Friday.

PLEASE be cautious on donating money for Japan online. There are lots of SCAMS. Check the site first. Read on How to avoid online scams

There are more victims like them in Japan. Let us help them. The latest death toll is expected to top 10,000.

In the Philippines, here is how to donate through the Philippine Red Cross.

Let us remember how Japan often donated when other countries have experienced disasters, such as when Hurricane Katrina impacted the United States. Check out the organizations that are working on relief and recovery in the region.

AMERICAN RED CROSS: Emergency Operation Centers are opened in the affected areas and staffed by the chapters. This disaster is on a scale larger than the Japanese Red Cross can typically manage. Donations to the American Red Cross can be allocated for the International Disaster Relief Fund, which then deploys to the region to help. Donate here.

GLOBALGIVING: Established a fund to disburse donations to organizations providing relief and emergency services to victims of the earthquake and tsunami. Donate here.

SAVE THE CHILDREN: Mobilizing to provide immediate humanitarian relief in the shape of emergency health care and provision of non-food items and shelter. Donate here.

SALVATION ARMY: The Salvation Army has been in Japan since 1895 and is currently providing emergency assistance to those in need. Donate here.

AMERICARES: Emergency team is on full alert, mobilizing resources and dispatching an emergency response manager to the region. Donate here.

CONVOY OF HOPE: Disaster Response team established connection with in-country partners who have been impacted by the damage and are identifying the needs and areas where Convoy of Hope may be of the greatest assistance. Donate here.

INTERNATIONAL MEDICAL CORPS: Putting together relief teams, as well as supplies, and are in contact with partners in Japan and other affected countries to assess needs and coordinate our activities. Donate here.

SHELTER BOX: The first team is mobilizing to head to Japan and begin the response effort. Donate here.

(Source via Yahoo)

You can also help Japan with one code snippet:

<br /> <mce:script type=”text/javascript” src=””//www.hellobar.com/hellobar.js”” mce_src=””//www.hellobar.com/hellobar.js””></mce:script> <mce:script type=”text/javascript”><!– new HelloBar(1,9126); // –></mce:script><br /> <mce:noscript><!–Help The Victims of the 8.9 Earthquake in Japan by Spreading Awareness and Aid. Visit http://goo.gl/wjZQz to donate.<br /> –></mce:noscript>

That code can be used on a Tumblr, WordPress or Blogger blog, too; here are some detailed instructions.

Check out other news agencies and organizations extending their hand to help out Japan. CNN has a comprehensive list on “Tsunami aid and relief: How you can help” too. The curated tweets below updates help extended to Japan.

It is a miracle to even survive the wrath of the Tsunami.

Japanese relief workers rescue a man who survived being buried for four days in the tsunami devastated remains of Ishimaki town, Iwate prefecture, Japan on March 15. (Source)

From Daily Mail

a 70 year survivor swaddles herself in blankets and gloves at makeshift shelter at Ofunato, Iwate Prefecture. Miraculously, she was found inside her house which had been washed away by the wall of water.
Her rescuers, from Osaka in western Japan, had been sent to the area for disaster relief. Osaka fire department spokesman Yuko Kotani said the woman was conscious but suffering from hypothermia and was being treated in hospital.

You can read more about this story here.

From ABC world news

A Japan Self-Defense Force member reacts after rescuing a four-month-old baby girl in Ishinomaki, northern Japan, Monday, March 14, 2011, three days after a powerful earthquake-triggered tsunami hit the country’s east coast. (AP Photo/The Yomiuri Shimbun, Hiroto Sekiguchi)
A beautiful, and much needed moment of joy.

“Two survivors in Japan, reunited by a rescuer. ”

This Tsunami victim waves to rescuers who spotted him floating on the roof of his home.

Via Washington Post

Hiromitsu Shinkawa clung to the roof of his home as he was pushed out to sea after a tsunami swept away his wife, the Associated Press reported. For two days, he drifted off Japan’s northeastern coast, trying to get the attention of helicopters and ships that passed by – to no avail.

On Sunday, a Japanese military vessel finally spotted the 60-year-old waving a red cloth. He was floating about 10 miles offshore from the earthquake-damaged city of Minamisoma, a Defense Ministry spokesman said.

Japanese troops used a small boat to pluck him from the ocean.

“I thought today was the last day of my life,” Kyodo News quoted him as saying.

Every rescue is a miracle as desperate search for survivors continues on:

Death toll from Japan quake and tsunami now at 1,353. At least 1,085 are missing and 1,743 injured. (see this photo gallery)

Many more are missing. I can’t even begin to imagine what this destruction is to their lives. While media is focusing on the nuclear meltdown, I will focus on the people that try to save lives, the survivors and Japan as a nation bent on recovering from all this, in time.

A dog stood loyally next to another dog that was injured or sick in Sendai, Japan.

Gary Bedard made this illustration below for Japan. He wrote ” My deepest and most sincere condolences go out to the people of Japan who have lost loved ones in the earthquake & tsunamis. This unimaginable disaster is one of the worst tragedies in recent history. Japan, I truly share your grief.”

..My deepest condolence for the families and friends Japan’s tsunami and earthquake victims. Here is how you can help Japan.

I will continue to source stories or tweets on the rescue operations.

March 15- Best to read about Fukushima nuclear power plant meltdown explained simply.

3:00 PM – Reuters: FLASH: Japan chief cabinet secretary says risk of explosion at building housing Fukushima Daiichi No. 3 reactor . More updates from Aljazeera live blog

March 13 – Japan’s top government spokesman says a partial meltdown is likely under way at the second damaged reactor of a quake-damaged nuclear complex, as authorities frantically tried to prevent a similar threat from a nearby unit following a catastrophic earthquake and tsunami. (read more)

7:51 PM- From Al-Jazeera: Ian Hore-Lacy, communications director at the World Nuclear Association, a London-based industry body, told Reuters he believed the explosion was due to hydrogen igniting, adding it may not necessarily have caused radiation leakage.

“It is obviously an hydrogen explosion … due to hydrogen igniting …If the hydrogen has ignited, then it is gone, it doesn’t pose any further threat,” he said.

6:00 PM- @adcarreon based at Urawa, saitama, Japan right now alerted me that ” Tokyo Electric Power Company confirm an explosion at one of its nuclear reactors in Fukushima Prefecture. Several were injured.”

Japan’s nuclear agency said that radioactive caesium and iodine had been detected near the number one reactor of the Fukushima 1 plant.

The agency said this may indicate that containers of uranium fuel inside the reactor may have begun melting.

Lets hope it doesn’t come to this….

The spread of radiation in the event of a nuclear fallout at Fukushima power plant is shown in a map below : (via @producermatthew)

A word of caution: the map might not be accurate based on this forum discussion:

However a comment in that video thinks that “That explosion that you see in these videos is exactly what happened to “Chernobyl”. This was the worst case scenario. The rods melted (melt down), and exploded. If you have ever seen pictures of the Chernobyl reactor building you can see the gigantic hole in the top where it blew up. Workers there were killed,? and injured during that explosion as well, as they were working to gain control.”

Is this scenario possible? Let us see the extent of the damage.

Peter Hayes, a nuclear expert, tells Al Jazeera “it’s still possible that the reactor workers can stabilise the situation” at the Fukushima Daiichi nuclear plant “if power is brought back, if coolant is brought into the reactor”, but “we’re really right at the precipice of a massive nuclear crisis”.

CNN reports that ” Japanese nuclear authorities said the cooling system had also failed at three of the four reactors at the Fukushima Daini plant — located in another town in northeaster Japan’s Fukushima prefecture.” A Yahoo article says that radiation is leaking from an unstable Japanese nuclear reactor after an explosion blew the roof off the facility in the wake of a massive earthquake.

The blast came as plant operator Tokyo Electric Power Co (TEPCO) worked desperately to reduce pressures in the core of the reactor.
“An unchecked rise in temperature could cause the core to essentially turn into a molten mass that could burn through the reactor vessel,” risk information service Stratfor said in a report before the explosion. “This may lead to a release of an unchecked amount of radiation into the containment building that surrounds the reactor.”

A BBC report indicates ” the amount of radiation released was “tiny”

In some of the reactors at the two Fukushima plants the cooling systems, which should keep operating on emergency power supplies, failed.

Without cooling, the temperature in the reactor core builds, with the risk that it could melt through its container into the building housing the system.

Analysts say a meltdown would not necessarily lead to a major disaster because light-water reactors would not explode even if they overheated.

But Walt Patterson, of the London research institute Chatham House, said “this is starting to look a lot like Chernobyl”.

He said it was too early to tell if the explosion’s aftermath would result in the same extreme level of radioactive contamination that occurred at Chernobyl.

The nuclear safety agency asserted Saturday that the radiation at the plants did not pose an immediate threat to nearby residents’ health, the Kyodo News Agency said.

@KeithMansfield reports that the Official #Fukishima nuclear exclusion zone quickly widens from 3 to 10 to 20km.

What now?

Things remain unclear at this point. Nuclear experts are unsure if it is a steam explosion. Monitoring is done 5 kilometers away.

Monitoring developments as it happens in here:

March 12

Japan has often donated when other countries have experienced disasters, such as when Hurricane Katrina impacted the United States. Check out the organizations that are working on relief and recovery in the region.

11:27 @jayr_12 Japan Meteorological Agency is still saying that there is danger still from tsunamis yet PHIVOCS already lifted tsunami warning in Batanes

10:12 PM- the highest wave monitored measures 70 cm high in Baler, Aurora. Some waves are still coming from Japan.

9:42pm – via Inquirer – The first waves struck the northeast coast of the country’s main island of Luzon at 6:00 p.m. (1000 GMT) and the east coast of the large southern island of Mindanao some two hours later, he said.

“We will have to monitor some more until 10:00 p.m. (1400GMT) and see what happens,” Solidum said, adding there were no immediate reports of damage or casualties.

4:00 PM- Alert level 2 has been raised in the 19 provinces that could be hit by tsunami between 5 p.m. and 7 p.m. and residents have been advised to be on alert for “unusual waves,” disaster officials said Friday, after an 8.9-magnitude earthquake struck Japan. (Source: inquirer.net)

This is a useful time guide

Tsunami guide

Click to enlarge. The red dots on the map show the current position of the real-time tsunami monitoring systems by DART (Deep-ocean Assessment and Reporting of Tsunamis), while the orange dots show tide gauges, these are tube-like devices measuring sea level and aid in detecting tsunamis.

Raw video from Japan below:

Here are curated tweets and photos of the damage