Ambient office  =  95 nanosieverts per hour

Ambient outside = 121 nanosieverts per hour

Soil exposed to rain water = 118 nanosieverts per hour

Carrot from Central Market = 91 nanosieverts per hour

Tap water = 84 nanosieverts per hour

Filter water = 80 nanosieverts per hour

       I have mentioned medical images with radioactive isotopes occasionally in this blog. Today I am going to delve into detail on a recent development in using radioisotopes in diagnostics and treatment. Researchers at the Utrecht University in the Netherlands have built a prototype device that combines a fluoroscope, a flat panel X-ray detector, combined with a gamma ray camera. They have used computer simulation to show how the device could be improved.
       Usually when creating such a hybrid device in the past that combined two different imaging modalities, one of the modalities was applied after the other. The problem with this approach was that if the patient moved at all between the application of the two different techniques, the resulting combination of images could be misaligned.
      The new device from the Utrecht team captures images from both techniques simultaneously which insures that the two images are properly aligned. This new device may be able to supply clinicians with anatomical data that cannot be captured by medical imaging systems currently in use.
      There was a previous attempt to combine fluoroscopy and nuclear imaging to simultaneously capture both images. Four gamma cameras with pinhole collimators were placed around the X-ray source on the opposite side of the patient from the X-ray detector. In order to create the final gamma image, the distribution of energy from the gamma emitter had to be combined into one image from the four separate images. Sandra van der Velden, the first author of the report on the Utrecht work, said, “This was computationally quite demanding, required complicated hardware integration, and resulted in a lower resolution of the nuclear images.”
       The Utrecht team has shown that they can capture useful images even when a single gamma camera with a cone-beam collimator is positioned behind the X-ray detector. Composite images that are created in this way are naturally co-registered. This means that diagnostic and therapeutic radioisotopes can be tracked within the anatomical context shown by the fluoroscopy.
       X-ray detectors are sensitive photon energies of 30-120 kiloelectron volts. Gamma ray detectors are sensitive to photon energies of 140 kiloelectron volts. This means that in the new device, the gamma photons are captured after they pass through the X-ray detector so system sensitive for gamma rays is degraded. In order to counter this, the Utrecht team has removed some of the lead shielding and structural aluminum from the flat panel X-ray receiver.
      The Utrecht experiments with radioactive sources in moving phantoms showed that the interference by the X-ray detector reduced the sensitivity by between 45% and 60%. However, the images were still free of artifacts and were useful. The spatial resolution of the gamma camera was not affected. The presence of a radioisotope in the field of view of the X-ray detector had no impact on its’s performance.
       Computer modeling indicates that the performance of the new device could be improved by reducing the thickness of the aluminum in the X-ray detector. This would reduce the attenuation of the gamma ray signal by 27% to 35%. This reduction of thickness in the X-ray detector would permit the gamma ray camera to be moved closer to the patient which will improve its resolution.
       While, the new device being developed in Utrecht will have broad application, the Utrecht team is focusing on a particular medical procedure called radioembolization for liver cancer. Currently nuclear imaging is used to predict the uptake of the radioisotope in the liver. Then, up to a week or more later, the treatment is carried out and monitored by the fluoroscope.
       Not only is the delay inconvenient to the patient, a catheter has to be inserted twice which carries its own dangers. If the hospital can carry out both procedures in the same day with the new device, it will be more convenient, safer and the results of imaging more accurate than the current technique.
      Van der Velden said, “We are currently working on a clinical prototype, which is at this moment being constructed. We plan to perform a clinical trial with that prototype, to show that radioembolization procedures can be improved. This will open up the possibility to perform it in one day, instead of the current two-step process, which takes one or two weeks.”

Ambient office  =  99 nanosieverts per hour

Ambient outside = 137 nanosieverts per hour

Soil exposed to rain water = 135 nanosieverts per hour

Carrot from Central Market = 74 nanosieverts per hour

Tap water = 91 nanosieverts per hour

Filter water = 86 nanosieverts per hour

Part 2 of 2 Parts (Please read Part 1)
        Martin Freer is the head of nuclear physics at the University of Birmingham and the director of the Birmingham Energy Institute. He said, with respect to the aging nuclear reactor fleet in the U.K., “It is clear they are showing their age. When they were originally built, they weren’t built to operate as long as they will.” He went on to say that the regulation of the nuclear power plants was very tight and there was no danger to the public or the environment, but there was definitely a need to shutter the old plants and build new ones. He also said that he hopes that the aging plants would make to their scheduled permanent closure dates in the 2020s but he was afraid that some would not. “It may just be a run of unfortunate incidents, or it might be a trend of reducing reliability. My suspicion is not all of them will make it through to the end.”
     EDF has said that it believes that its investments in maintenance will allow the plants to continue to operate at capacity for their licensed lifespans. EDF has spent over one hundred and thirty million dollars in the past six years on the issue of graphite cracking. EDF bought the nuclear power plants in 2008 and their output increases until 2016 but is now declining.
       Brian Cowell is the managing director of generation at EDF. He said, “EDF Energy’s seven advanced gas-cooled and one pressurised water nuclear power stations [Sizewell B] are delivering at ever better levels thanks to sustained investment and the expertise accumulated over more than 40 years of operation.”
      Several of the old power plants are currently going through safety reviews by the U.K. Office of Nuclear Regulation. Heysham 1 and Hartlepool both had their periodic safety review in January. Heysham 2 and Torness will have their reviews next January.
       The Japanese nuclear technology firm Hitachi has been working on a nuclear power project for the Welsh island of Anglesy. It has just notified the U.K. government that it will cancel the project unless the U.K. commits new funding to allow the completion of the twenty-six billion dollar project.
       Last November, another Japanese nuclear technology company, Toshiba, abandoned a U.K. nuclear power project in Cunbrai. U.K. utilities have already pumped hundreds of millions of dollars into the National Grid to build the transmission lines that would have been needed to distribute the power to be generated by the planned power reactor. U.K. rate payers will be paying for those wasted hundreds of millions of dollars with surcharges on their electrical bill for decades to come.
       One of the main reasons that these projects may be or have been abandoned is that the cost of renewable energy projects has been dropping rapidly. It is now cheaper to build renewable energy projects than nuclear power projects. Greg Clark is the government minister in charge of the U.K. energy board recently told Parliament, “The cost of renewable technologies such as offshore wind has fallen dramatically, to the point where they now require very little public subsidy and will soon require none. We have also seen a strengthening in the pipeline of projects coming forward, meaning that renewable energy may now not just be cheap, but also readily available.”

Ambient office  =  97 nanosieverts per hour

Ambient outside = 164 nanosieverts per hour

Soil exposed to rain water = 166 nanosieverts per hour

Broccoli from Central Market = 45 nanosieverts per hour

Tap water = 116 nanosieverts per hour

Filter water = 97 nanosieverts per hour

Part 1 of 2 Parts
       The U.K. has eight nuclear power reactors. They provide about twenty percent of the electricity for the country. Seven of these plants utilize what is referred to an advanced gas reactor (AGR) design. The oldest of these reactors was built forty-three years ago and the youngest was built 30 years ago. They were intended to have a lifespan of about thirty-five years.
         Two of the reactors had to be closed temporarily in January which resulted in a twelve percent drop in nuclear powers contribution to the national grid. There have been multiple outages recently due to either safety checks or engineering work that ran over its allotted schedule. When nuclear power plants have to reduce their output or be shut down temporarily, the carbon emissions of the nation rise because the shortfall is usually made up be firing up dormant fossil fuel power plants.
         EDF is a French utility company which is primarily owned by the French government. It is the owner of the U.K. fleet of nuclear power reactors. As the reactors reached the intended end of their operational life, EDF applied to the U.K. regulators for and received new licenses to extend the reactors lives into the 2020s. Now there are fears that aging and deteriorating U.K. nuclear infrastructure may reduce reactor output or even require that some U.K reactors be shuttered and decommissioned before their revised licenses run out.
          Iain Staffell is a lecturer in sustainable energy at Imperial College. He recently compiled information on the output of the nations nuclear power reactors. He said, “Just as Toshiba and Hitachi have pulled out of building new reactors, we have one third of the existing nuclear capacity unavailable either for maintenance or because their maximum power has been reduced as they get older. Many of our reactors were built in the late 70s, and like your typical 40-year-old they aren’t in peak physical condition anymore.”
       Reactor 3 is an AGR at the Hunterson B nuclear power station on the west coast of Scotland. It was taken offline last March because more cracks than were anticipated were found in the graphite in the core of the reactor. The graphite acts as a moderator to slow down neutrons but years of bombardment by neutrons has altered the structure of the graphite.
       EDF had originally said that Reactor 3 would be back online by November of 2018 but now they believe that they will have it working by the end of April 2019. The other reactor at Hunterson is scheduled to be back online by the end of March 2019. EDF will only be able to restart the two reactors at Hunterson if their safety report is approved by the U.K. nuclear regulatory agency.
      EDF just announced this week that it was changing the schedule for the reopening of its Dungeness nuclear power plant in Kent from February to April. The closure was due to maintenance of the pipes that carry steam from its broiler. EDF hopes that Dungeness will be back on line before the Hinkely B reactor in Somerset will have to be taken offline for inspection of the graphite in its core. If more cracks that expected are found, that would mean that it will have to be offline longer than scheduled.
Please read Part 2