MINAMISOMA, Japan — Six months after it was struck by Japan's triple disaster, Minamisoma no longer fits the description of a nuclear ghost town.

When GlobalPost first visited in early April, the city was almost deserted. Its pre-disaster population of 71,000 plunged to just 10,000 in the wake of the nuclear accident at the nearby Fukushima nuclear power plant, as busloads of residents took flight from radiation leaks.

The population has since increased, but Minamisoma remains a city struggling to come to terms with its place at the center of Japan's worst-ever nuclear accident.

The most populous parts of the city lie about 25 kilometers (15 miles) northwest of the plant, but radiation levels in some areas are high enough for the authorities to advise residents to prepare to leave in case the situation at the facility worsens.

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Unconvinced by official reassurances that their home is safe, 30,000 residents still refuse to return.

"Pediatric clinics here can no longer operate because there are too few children," says Kyohei Takahashi, a gynecologist who now acts as a community doctor and unofficial counselor.

"Overall, the number of doctors is down by 20 percent, and many nurses and other medical staff have taken their children out of town. Health services here are facing a tough situation. But we are doing our best."

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With the help of an architect, he visits the homes of mothers of young children, measures and cleans up contaminated spots, and dispenses advice on how they can protect themselves.

Takahashi, 72, was among those who fled immediately after the nuclear crisis began, only to return a few days later to help relieve the stress on the city's strained health services.

Life for those residents who, like Takahashi, have chosen to return continues against a backdrop of anxiety and uncertainty.

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"Lots of people in this area were forced to leave, and some stayed in evacuation centers for as long as six months," says Tomoyoshi Oikawa, deputy director of Minamisoma municipal general hospital.

"Under those conditions, their health has deteriorated. Some have pre-existing conditions — high blood pressure, diabetes and liver disease — and the symptoms have worsened because of their circumstances. Some people are also showing signs of psychological illnesses because of radiation fears."

Much of the current uncertainty stems from a dearth of expert knowledge of the long-term effects of exposure to relatively low levels of radiation of between one millisievert [mSv] a year — the national allowable limit set by the government — and 20 mSv a year, a provisional threshold applicable only to people in Fukushima prefecture.

Four months after the disaster, Oikawa's hospital started offering full-body radiation scans to reassure residents. So far the hospital has screened about 2,000 people, none of whom have displayed levels high enough to cause concern.

"We look at the thyroid gland and for the presence of radioactive cesium throughout the body. In adults, we must be careful about cancers of the bladder and brain, and so on. These illnesses could become a big problem in the future. We have to be on our guard.

"We must also be very vigilant about possible thyroid carcinogenesis in children in particular, juvenile lung cancer and leukemia."

Officials and campaigners are divided over how the city should respond to protect residents, particularly children.

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About a dozen schools in at-risk parts of the city resemble construction sites, as crews hired by the council remove layers of contaminated topsoil from playing fields, wrap and bury it, then cover it with clean soil. Until the work is finished, children as young as 5 must take classes in other areas before being bused back for collection by relatives.

"My grandson is only 6, so we thought it was best to evacuate at first because of the radiation," says Keiko Sato, who has arrived at Haramachi No. 3 primary school to meet her 6-year-old grandson, Yuta.

"People of my generation are old enough for the risks to be low, but the children here have many years ahead of them. We don't want them to put them at risk.

"He has to wear long-sleeved shirts and trousers, a mask and a hat. If he doesn't, he won't be allowed on the bus."

With decontamination measures under way, the central government is preparing to remove Minamisoma and other locations from the evacuation-warning list at the end of this month, meaning children such as Yuta could be studying in their old schools by around the middle of October.

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But Greenpeace and smaller civic groups believe residents of hotspots in Minamisoma and other locations near the edge of the 20-kilometer exclusion zone (about 12 miles) around Fukushima Daiichi should be offered government help to evacuate immediately.

"The people of Fukushima prefecture are being used as human guinea pigs," says Seiichi Nakate, leader of the Fukushima Network for Saving Children from Radiation.

"The [20 mSv] threshold has been set deliberately high to prove that there have been no health side-effects from radiation. I reject the idea that the people of Fukushima should be told it is safe to be exposed to 20 millisieverts a year when the standard for people in the rest of Japan is just one millisievert."

Angered by the slow official response to local public health concerns, Minamisoma's residents have taken it on themselves to measure radiation in dozens of locations and decontaminate them.

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"First of all, we measure the radiation levels — we're doing that in about 100 places — that way we can identify places with high levels and mark them down for decontamination," says Tsunetoshi Komatsu, a member of the Haramachi residents' association.

"Once we've done an initial cleanup, we would like people to buy decontamination equipment and keep the area around their own homes clean. Ideally the equipment would be public property, for people to use whenever they need it. That way, over time, we can reduce a spot that measures two microsieverts an hour to, say, 0.1 microsievert, or one millisievert over the course of the year."

Takahashi hopes evidence that local decontamination programs are having the desired effect will persuade spooked families to return and lift the city out of its nuclear limbo.

He will not rest, he says, until radiation levels in every part of Minamisoma are low enough for children to be born and raised with zero risk to their health.

"This has been a very steep learning curve for us. We have checked dozens of places for radiation, and checked again. As long as we continue our decontamination efforts, we can gain confidence that this will be a town where children can again live in safety.