Lessons to belearnt from Delhi radiation incident

The Hindu

Date:15/04/2010 URL: http://www.thehindu.com/thehindu/seta/2010/04/15/stories/2010041551311400.htm
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Lessons to be learnt from Delhi radiation incident

Photo: K. PIchumani


The source: Virtually all instances of steel contamination seem to have been caused by radioactive sources which came with imported scrap. —
At 12:45 hrs on April 7, 2010 the Atomic Energy Regulatory Board (AERB) received a fax message from Indraprastha Apollo Hospital, Delhi stating that a scrap metal dealer admitted to the hospital showed symptoms suspected to be caused by radiation exposure.
Six more workers who also exhibited similar symptoms were admitted elsewhere. On receiving the information, two AERB officers who were already in Delhi inspected the shop and its surroundings, identified high radiation levels and promptly shielded some suspected high radiation locations with metal sheets to reduce the radiation levels.
As per the procedure in place, a team of scientists from Bhabha Atomic Research Centre (BARC)and the Narora Atomic Power Station , mobilized by the Crisis Management Group of the Department of Atomic Energy (DAE) and scientists from AERB visited the site again and restored normalcy by safely removing the sources into appropriately shielded containers. By April 9, 2010, the radiation levels at the site became normal background radiation levels.
“It was indeed a difficult operation; we collected cobalt-60 sources of high strengths in the form of wires under trying circumstances and secured them in special containers. We instituted strict dose control procedures which ensured that the radiation doses to us were within limits,” said Dr. K.S.Pradeep Kumar, Senior Scientist and Head, Emergency Response System and Methods Section.
“We learnt a few lessons. The team from Narora brought many tools and accessories; their support proved to be very crucial,” he clarified. He paid compliments to the excellent cooperation extended by the Delhi police.
A handful of radiation incidents in which persons got exposed to very high radiation doses occurred in India. Most of the cases were because of gross violation of safety procedures in handling industrial gamma radiography sources.
In the most serious case, a railway gang man received high dose as he kept gamma source in his pocket for a few hours. The source was lost in transit because of negligence of radiation workers in a company. Follow up action led to the winding up of the company.
The victim pocketed the shining object assuming that it is valuable. He was admitted into BARC Hospital initially for three months and was followed up for one and a half years. He survived after several skin drafts and other procedures.
The Delhi incident was a serious one. That such incidents were rare would be poor consolation for those seven persons who were exposed to radiation. There must be zero tolerance to such events.
AERB had suggested several preventive measures ( The Hindu, Nov 13, 2008). In the light of a few steel contamination incidents, AERB proposed to put in place a multi layered radiation check system ( The Hindu, February 26, 2009). These need closer review, strengthening and more effective enforcement.
Many scrap dealers have bought radiation monitors. The proposal to erect radiation monitors at major ports is yet to be implemented. Since virtually all instances of steel contamination seem to have been caused by radioactive sources which came along with imported scrap, radiation monitors must be installed urgently at all ports. The radiation incident at Delhi must be considered as the final wake up call. There are plans to equip selected police stations in major cities with radiation monitors. The task is humongous but achievable through dedicated efforts.
Radiation exposure from “orphan sources” was a topic of discussion in many meetings held by the International Atomic Energy Agency (IAEA) since 1998.An initial review indicated that, more than 110 countries may not have minimum infrastructure to properly control radiation sources (IAEA, 1999).
Since 1990, 300 radioactive sources were recovered from Georgia. There were instances in which intense radiation sources used in agricultural research such as mutation studies were found abandoned in trucks
In the United States alone, the Nuclear Regulatory Commission (NRC) annually receives about 200 reports of lost, stolen or abandoned radioactive sources. This is disconcerting as U.S. has a stringent regulatory system. AERB receives less number of reports annually, presumably because we have far less number of sources in use. Also as in U.S., AERB has a very effective system to track high intensity sources.
K.S. PARTHASARATHY
FORMER SECRETARY, AERB
ksparth@yahoo.co.uk
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New Health Studies on A-bomb Survivors

Published on: August 28, 2010 - 23:04

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• Panorama

By Dr KS Parthasarathy
On August 6, 2010, Hiroshima observed the 65 anniversary of the atom bombing. The anniversary of Nagasaki bombing was on August 9. For the first time, United States sent an envoy to Hiroshima.
The US ambassador to Japan, Mr John Roos, laid a wreath ‘to express respect for all of the victims of World Ward II’. Britain and France, its World War II allies sent their first diplomats to the ceremony, indicating support for the goal of nuclear disarmament. Mr Ban Ki-moon, the United Nations Secretary General is the first UN Chief to attend the function. Everyone wants to draw attention to the urgent need to achieve global nuclear disarmament.
In the hurry and excitement of global politics we may forget the priceless research on biomedical effects of radiation carried out by the Atomic Bomb Casualty Commission and its successor Radiation Effects Research Foundation (RERF) which was set up in 1975.
From the 280,000 survivors in the two cities, the RERF scientists established fixed cohorts or cohorts to provide epidemiological and clinical data on the health status and mortality of survivors and their children. The latest issue of RERF update, a publication from RERF, noted that RERF and ABCC scientists have been evaluating, documenting and publishing for the past 63 years, the long-term health effects associated with the ionising radiations emitted by the A-bombs in Hiroshima and Nagasaki.
"Much of the research of ABCC, and now RERF, has focused upon characterisation of the effects of the A-bomb radiation exposure on the immunological parameters in the survivors. Those studies are being conducted in an aging population in one of the longest-living and most homogeneous population in the world." (RERF update, 2010).
The US National Institute of Allergy and Infectious Diseases (NIAID) is funding the project. RERF researchers will be able to define the effects of ionising radiation on aging of the human immune system and elucidate the underlying mechanism.
The project is possible because they can use the large, unique data base and bio-samples from the 63-year follow up of A-bomb survivors. Co-investigators from five US and Japanese institutions will provide their expertise and methodologies for the success of the project.
The main focus of the project is immunosenescence, the gradual deterioration of the immune system with aging. The process involves many vital activities. The host’s ability to respond to infections may degrade; the development and retention of long term immune memory including the one generated by vaccination may diminish; the immune cell turnover may alter and an imbalance between the innate and adaptive immunity may potentially cause enhanced and persistent inflammatory responses.
When successfully concluded the studies may lay a foundation to explain some of the long term health effects observed in A-bomb survivors.
There is clear evidence for excess leukaemia and solid cancers among the exposed population. These observations helped the International Commission on Radiological Protection to recommend dose limits to workers and members of the public.
Recently researchers noted an increase is non cancer-diseases among the survivors. They can explain this only if their understanding of the defects in the individuals’ immunological system over time and with prior radiation exposure improves. They hope that such studies will provide a solid, scientifically grounded basis for risk assessment, regardless of the disease outcome of interest (RERF Update, 2010).
"It will open opportunities for prophylaxis, prevention and treatment of the resulting disorders", the researchers concluded. The latest RERF update summarised thirteen areas of research. RERF and its collaborating subcontractors will conduct four projects for elucidating the effects of ionizing radiation and aging on blood-derived stem cells, dendritic cells and their precursors (these are crucial in triggering immune response against infections) and on vaccination responses. The plan to develop an integrated scoring system for human immune competence as it relates to aging and ionising radiation.
The Departments of Clinical Studies in Hiroshima and Nagasaki have been carrying out Adult Health Study (AHS) for over 50 years. Summarising the work of these departments, Fuliwara and Akahoshi clarified that the objective of AHS is to determine radiation risks for diseases that cannot be documented adequately by the larger mortality study called Life Span Study (LSS) (RERF Update, 2010).
These studies include the effects of radiation on the risk of non fatal heart disease or stroke, high blood pressure, various benign tumours and other adverse health effects.
About 20,000 subjects in the AHS group have provided biological samples once every two years from 1958. The repeated samples proved invaluable as they are seldom available in any other project anywhere in the world.
RERF is carrying out a comprehensive study (F1 Clinical Study) on nearly 12,000 children of A-bomb survivors. It evaluates the possible association between radiation exposures of their parents and the frequency of diseases such as heart disease, stroke, hypertension and diabetes. Now their average age is 50; they have developed little disease thus far and there is scope for long term study.
From 1978, AHS group included 2000 additional high dose groups and nearly 1,000 (all available) persons who were exposed to A-bomb radiation while they were in their mother’s womb.
The relationships between exposure to radiation and non cancer -diseases were not expected. Recently, researchers discovered that radiation is associated with premature menopause. This may cause earlier onset of increase in cholesterol levels and cardiovascular disease.
RERF researchers are studying liver stiffness, chronic kidney disease and cardiovascular disease and their possible relationship with radiation exposure.
The clinical evaluation of nearly 12,000 children of A-bomb survivors provided no evidence of an increased prevalence of multi-factorial diseases in relation to their parental exposure.
RERF scientists noted that the prevalence of cataract increased with radiation dose with a dose-effect threshold that was much lower than previously believed.
RERF is continuing with intensive and extensive studies on human diseases’ with unparalleled resources at its command. Spin offs from these may help fight gruesome diseases. This may be the notable contribution from the dastardly event which occurred over six decades ago. PTI

Cataract risk for unprotected interventional cardiology personnel

  

September 1, 2010


Cataract risk for unprotected interventional cardiology personnel
K. S. PARTHASARATHY

ULTRA SENSITIVE: The eye lense is one of the most radiosensitive of the tissues. Photo: K. Ananthan
Now it is official. In two separate studies, researchers supported by the International Atomic Energy Agency (IAEA) recently concluded that interventional cardiologists and associated workers who have not used radiation protection accessories have significantly elevated incidence of radiation associated eye lens changes; and that there is urgent need to educate them in radiation protection to reduce the likelihood of cataract.
Published studies
Radiation Research (June 28, 2010) and Catheterization and Cardiovascular Interventions (June 14, 2010) two peer reviewed journals have published these studies.
There are three main forms of cataract according to its anatomic location: nuclear, cortical and posterior sub capsular (PSC). Among the three forms of age-related cataract, PSC is the least common but this form is most commonly associated with exposure to ionizing radiation. Researchers in both studies demonstrated a dose-dependent, increased risk of posterior lens opacities for interventional cardiologists and nurses when they did not use radiation protection accessories.
Larger cohort needed
Though a larger cohort is needed to confirm the findings, the results suggest that radiation protection measures for eyes must be in place.
In both studies, two independent specialists each trained in the recognition and evaluation of characteristic, radiation-induced lens changes, examined the eyes of each participant after full dilation.
The study published in Radiation Research showed that the interventional cardiologists have 3.2 times more risk than for unexposed controls. For nurses and technicians, the relative risk was 1.7 times more.
The study groups consisted of 116 exposed individuals (interventional cardiologists: 58 and associated workers :) and 93 similarly aged non-exposed individuals.
The paper published in Catheterization and Cardiovascular Interventions showed that the relative risk for interventional cardiologists was 5.7 and for nurses and paramedical staff, it was five, compared to unexposed controls. This group contained 67 physicians and nurses and 22 age and sex matched health care professionals not working in interventional medicine.
“The lens of the eye is one of the most radiosensitive tissues in the body and exposure of the lens to ionizing radiation can cause cataract” the researchers wrote in Radiation Research.
“Ionizing radiation exposure to eye lens results in characteristic progressive changes leading to opacification or clinical cataract. While initial, early stages of such opacification may not cause visual disability, the severity of such changes increases progressively with dose until vision is impaired and cataract extraction surgery is required,” the researchers warned.
“Because of its location along the visual axis of the lens, relatively minor PSC can have a great impact on vision,” the researchers cautioned.
Cataract sets in early, if the dose is larger. Cumulative x-ray doses to the lenses of interventional cardiologists and staff can be very high. They often remain close to the patients for several hours a day during cardiac interventional procedures. Patients scatter x-rays.
Combining doses
The researchers evaluated eye lens dose of each participant by combining doses measured from several catheterization laboratories with the subject's reported annual workload (number and kind of procedures carried out).
In 2007, the International Commission of Radiological Protection (ICRP), in its latest recommendation, reiterated the suggestion from recent studies that the lens of the eye may be more radiosensitive than previously considered.
Surveys during various IAEA training courses in which cardiologists from 56 countries attended indicated that only 33-77 per cent interventional cardiologists used dose measuring badges routinely. They did not use protective accessories universally.
An AERB workshop on “Radiation safety in interventional radiology including cath lab” in April 2009 highlighted the need for formal training in this important area. Taking into account its potential to deliver high radiation doses, the Atomic Energy (Radiation Protection) Rules 2004 prescribed that all such equipment must have a “license”, the highest form of regulatory documentation and control.
Interventional cardiologists must receive appropriate training and accreditation to use radiation equipment optimally without undue risk. AERB and the relevant professional associations must take the lead in achieving this objective.
Let us learn from the experience of advanced countries which acted promptly when patients suffered skin injuries. The new findings on cataract must speed up a comprehensive programme of training.
The training material is freely available at: http://rpop.iaea.org/RPOP/RPoP/Content/AdditionalResources/Training/1_TrainingMaterial/Cardiology.htm
Raja Ramanna Fellow, Department of Atomic Energy
(ksparth@yahoo.co.uk)
Keywords: Radiation risk, cataract, International Atomic Energy Agency, cardiologists, eye lens changes, Radiation Research, Catheterization and Cardiovascular Interventions

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