AERB not quite subatomic

The Economic Times

Tue, Apr 19, 2011 | Updated 08.09AM IST

Atomic Energy Regulatory Board not quite subatomic

By K S Parthasarathy

Recently, the independence of the Atomic Energy Regulatory Board (AERB) and its effectiveness attracted legitimate media scrutiny. Is AERB empowered to act?

The central government set up AERB in November 1983 and empowered it to enforce sections 16, 17 and 23 of the Atomic Energy Act , 1962. These cover control of radioactive substances, administration of the Factories Act, 1948 in the installations of the department of atomic energy (DAE) and enforcement of special provisions of safety. AERB enforces safety-related rules under the Atomic Energy Act.

There is a general perception that AERB is subservient to the department of atomic energy. A review of AERB's functioning does not support this view. Is AERB acting?

From AERB's annual reports, I counted over 50 regulatory actions such as reducing power levels of nuclear power reactors and shutting them down for specified periods to carry out appropriate tests and evaluations, among others which AERB imposed on DAE units.

Nuclear Power Corporation (NPCIL) may have felt that at times AERB has been a little too harsh. NPCIL implemented AERB directives without preferring appeals, even when it involved considerable expenditure.

During 1988 and 1989, AERB restricted the power levels of units 1 &2 of the Madras Atomic Power Station one after the other following failure of their inlet manifolds. It permitted NPCIL to restore power levels in 2003 and 2006, only after substantial upgradations and design changes.

Unit 1 of the Narora Atomic Power Station suffered a serious fire incident on March 31, 1993. AERB decided against the start-up of unit 2 of the Narora Atomic Power Station, pending complete investigation of the fire incident and implementation of the remedial measures recommended by two specialist committees set up by NPCIL and AERB,

The board ordered sequential shut down of each unit of the pressurised heavy water reactor (PHWR) stations for inspection of its turbine, generator and associated components to assess its state of health and fitness for continued operation and to modify the turbine roots. NPCIL complied with the directive.

In 1994, subsequent to the failure of the inner containment dome of unit 1 of the Kaiga Atomic Power Project, AERB suspended the civil construction activities related to the inner containment domes of Kagia unit 2, and units 3 and 4 of the Rajasthan Atomic Power Project. AERB lifted the hold only after satisfactory resolution of related safety matters.

In 2004, AERB prescribed 'formal and elaborate retraining and relicensing of all the frontline operating staff and the station management personnel' following a safety-related incident at the Kakrapar Atomic Power Station.

In 2007, the AERB withdrew the construction licence of units 5 and 6 of the Rajasthan Atomic Power Project when it found poor industrial safety status. It lifted the hold only after NPCIL ensured enhanced safety arrangements.

As directed by AERB, specialists re-evaluated the seismic safety of units 1 and 2 of the Tarapur Atomic Power Station which was designed as per the standards prevailing in 1969. NPCIL remedied the shortfalls by following international practices. NPCIL installed seismic sensors at all plants as stipulated by the AERB.

AERB imposed restrictions on many hospitals and other installations. AERB took action against the installations of the Oil & Natural Gas Commission, when it found lapses.

The list of AERB actions is indicative and not exhaustive. AERB enjoys functional autonomy; it takes its own decisions on merit. I was a witness to or participated in AERB activities closely since 1984. I do not recall a single instance in which DAE or others influenced AERB.

The five-member board has more members from outside the AEC family, it reports directly to the Atomic Energy Commission (AEC) and not to an individual. AEC has the status of the government of India.

AERB has many specialists from outside the DAE in its committees. However, a robust regulatory system cannot rely on good intentions alone. AERB must be made a statutory organisation.

Recently, the Prime Minister stated that AERB's legal status will be enhanced. Some critics feel that ARRB "merely serves as a lapdog of the Department of Atomic Energy". Though the statement makes good copy, many regulatory actions of AERB from 1983 do not support the criticism. They show that a lapdog may just bark, but AERB actually bites.

I hope that AERB will continue to function effectively as it always did regardless of the perceived infirmities of its legal status.

(The author is a former secretary of the Atomic Energy Regulatory Board, government of India)

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Published: January 19, 2011 23:43 IST | Updated: January 19, 2011 23:43 IST January 19, 2011

CT scans best to uncover body packed drugs

http://www.thehindu.com/health/medicine-and-research/article1103201.ece

The Hindu THE CAUTION: Though CT can be used for detecting concealed drugs, low-dose protocols are needed to make it safer for people undergoing the procedure. Photo: K. Murali Kumar

CT has a sensitivity of 100 per cent, while others like digital radiography and digital X-ray have only 85 per cent and 70 per cent respectively

During 1924, Captain T W Barnard, Director, Erstwhile Institute of Radiology at the General Hospital, Madras, helped the police to locate a gold chain in the stomach of a thief by x-raying him.

A few years later, Barnard found precious stones secreted in small cavities inside the cheeks of the women of a band of criminals by x-raying them; police suspected that they stole a large quantity of jewels. Identifying drugs in place of gold will be difficult.

Body packing

The US Customs and Border Patrol (CBP) seize over a million pounds of drugs (mainly marijuana, cocaine and heroin) annually. Eighty percent of the smugglers caught by CBP practice ‘body packing' of these illegal narcotics.

The May 2008 issue of the Applied Radiology describes the practice of body packing as the trafficking of illicit drugs within the gastrointestinal tract or vagina. According to the journal, body packers are also known as ‘swallowers,' ‘internal carriers,' ‘couriers' or ‘mules.'

Detects cocaine

A study presented recently at the annual meeting of the Radiological Society of North America (RSNA) identified computed tomography (CT) as the best way to detect cocaine in the body of a ‘mule.'

Dr Patricia Flach, a radiologist at University Hospital of Berne and Institute of Forensic Medicine of Berne in Switzerland and colleagues analyzed images from 89 exams using various imaging methods (CT:27; Digital X-ray: 50 and low-dose linear slit digital radiography (LSDR):12) and performed on 50 suspected drug ‘mules' over a three-year period at University Hospital.

The study group included 45 men and five women aged between 16 and 45. Researchers identified forty-three of the suspects as drug mules. They compared the radiologic findings with a written record of the drug containers recovered from the faeces of suspects.

CT imaging the best

CT imaging allowed the physicians to see all the drug containers, especially when they knew what to look for. Thus the sensitivity of CT is 100 per cent. LSDR had a sensitivity rate of 85 per cent; digital x-ray was able to identify the presence of cocaine containers only 70 per cent of the time.

Intestinal contents are messy and non-uniform in consistency. According to Dr Flach, there were positive findings on CT that were clearly not detectable on conventional x-rays due to overlap of intestinal air, faeces or other dense structures.

The coating and manufacture of the containers changed their appearance, especially on CT images. Rubber-coated condoms filled with cocaine appeared hyper-dense, or white, on CT, while other containers of similar size with plastic foil wrapping appeared iso- to hypo-dense or grey to black.

Dr. Stephen J. Taub, Division of Toxicology, Department of Emergency Medicine, Beth Israel Deaconess Medical Centre, Boston, USA and colleagues stated that body packers usually carry about one kg of drug, divided into 50 to 100 packets of 8 to 10 g each. Smugglers have devised automatic processes to pack drugs densely into latex sheaths or condoms.

False negatives

Writing in The New England Journal of Medicine, they noted instances in which physicians interpreted two plain abdominal radiographs as negative. The suspects subsequently passed 106 and 135 packets.

Plain abdominal radiographs may be useless to identify drugs in the ‘mules.'

When the law enforcing authorities suspect an individual of being a drug ‘mule,' they often seek the help of radiologists to detect quickly the presence of drugs concealed in the body.

According to the researchers, cocaine containers, which may be swallowed or inserted in the vagina or rectum, can be as large as a banana or as small as a blueberry.

“In these cases it is important for us to know that we have identified all the drug containers in a body, both for legal purposes and for the health of the patient,” Dr. Flach said.

“However, there was no research telling us which imaging modality was best in detecting cocaine containers in the stomach, intestines or other body orifices.”

Higher dosage

CT exposes the suspects to higher doses of ionizing radiation. It is obviously of concern while imaging healthy people.

“CT is the way to go," Dr. Flach said. "But low-dose protocols need to be implemented to ensure the safety of the people undergoing the procedure,” she cautioned.

Raja Ramanna Fellow, Department of Atomic Energy ksparth@yahoo.co.uk

50 years of CIRUS: some unforgettable memories

S & T

Published: December 23, 2010 01:41 IST | Updated: December 23, 2010 01:57 IST December 23, 2010

50 years of CIRUS: some unforgettable memories

K.S. PARTHASARATHY 

OLD WARHORSE: Research Reactor CIRUS at the Bhabha Atomic Research Centre at Trombay. Photo: V.V. Krishnan

On December 18, the scientists and engineers in the Department of Atomic Energy (DAE) celebrated the Golden Jubilee of CIRUS and the Silver jubilee of DHRUVA. The organizers invited everyone who was associated with the two research reactors. It was an emotional homecoming for many, especially for those who retired decades ago.

The 40 MW research reactor attained criticality on 10{+t}{+h} July 1960. It was constructed under Canadian assistance. India and Canada shared the cost of about $14.14 million. CIRUS, the workhorse of BARC is a symbol of the advanced developments in nuclear science, engineering and technology in India.

Dr Bhabha chose this heavy water moderated, uranium metal fuelled reactor as it would be a powerful tool for research. Also Dr W.B. Lewis, the eminent scientist who led the designers of the reactor was close to him in his Cambridge days.

Veterans recalled the teething problems they faced, the ways in which they solved them and their unforgettable memories. The 188-page commemorative booklet which describes them is a lucidly written, technical document, an A to Z cookbook on research reactor operation and maintenance!

Priceless experience

The reactor operation and maintenance group acquired priceless experience by studying the failure data of components such as valves.

Floating materials, mainly plastic waste and seeds and leaves from ever expanding mangroves, clogged the travelling water screens in the sea water inlet system; silt accumulation in the gland vent ports damaged the pumps. Scientists addressed these issues promptly.

“ In a hurry to start the reactor early, Bombay municipal water was charged to the high head storage tank ( ball tank) and was used in the re-circulating coolant water circuit” Shri S.M. Sundaram, former Director, Reactor Operation and Maintenance Group (ROMG) recalled. The total dissolved solids (TDS) such as silica in water got deposited on the fuel cladding, reducing coolant flow and damaging many of them at higher power level.

The Canadians did not face such a problem in their reactor; they used fresh water from Ottawa River. Sundaram and his team purified water using ion exchangers and solved the problem.

He remembered that then he worked against the orders from their superiors. Bhabha tacitly supported them. “…he said that there may be rare occasions when one may need to disregard the orders of his superior, for a good cause”.

By October 1963, they could raise the power level to 40 MW.. “ever since, CIRUS has been the workhorse of Indian atomic research programme”, Shri N. Veeraraghavan, former Associate Director, ROMG recalled.

He remembered that Dr Bhabha addressed a meeting in the indoor games room in the Old Yacht Club Building, which was attended by CIR project related scientific community sometime end of 1959 or early 1960.

“Bhabha expressed full confidence in the ability of Indian engineers in the production of indigenous, pure natural uranium and its fabrication into fuel rods for the initial loading of the CIRUS reactor”, Shri Veeraraghavan said .

Very bold commitment

“ As I see it today, this was a very bold commitment at that time, which ended happily for all, especially the chemical and metallurgical engineering staff that really worked hard and met the commitment with the loading of indigenous uranium fuel for the first “criticality” of CIRUS reactor,” he added

Most of the members of the newly recruited scientific and engineering staff for CIR operations sent for training to Canada during 1956-1957 came from very conservative backgrounds. They were from different regions of the country and spoke different languages. Most of them were strict vegetarians.

Dr M.R. Srinivasan, former Chairman, Atomic Energy Commission (AEC), delivered a few lectures to them. Bhabha asked him to take them to the Taj Hotel so that they would learn to use knife and fork before going to Canada for further training!

Dr P.K. Iyengar, former Chairman, AEC, recalled that the training school programme which Bhabha spearheaded helped national integration; it brought people from different parts of the country together.

Heartbroken

“I am truly heartbroken to learn that this old workhorse will be put to sleep at the end of this year for reasons that are anything but technical” the words of Shri S.K. Sharma, former Director, Reactor Group, truly reflected those of many others present.

“But then those are the ways of the world that we live in,” he consoled everyone.

In his inaugural address Dr R.K. Sinha, Director, BARC, stated that the CIRUS reactor provided research and development inputs to the nuclear power programme in the country.

It provided a platform to train engineers and technologists in the area of reactor management.

“This is an occasion to reflect on the past and to pay our gratitude to our elders” Dr Srikumar Banerjee, Chairman, AEC, said while addressing the gathering.

K.S. PARTHASARATHY, Raja Ramanna Fellow, DAE

(ksparth@yahoo.co.uk)

Keywords: CIRUS, Department of Atomic Energy

CT: cancer risks for the elderly

Online edition of India's National Newspaper
Thursday, Dec 02, 2010

The study showed cancer incidence from CT scans was less threatening

— photo: K. Murali Kumar

The focus: The study estimates cancer risk to persons above 65.

In a paper presented at the 96 {+t} {+h} Scientific Assembly and Annual Meeting of the Radiological Society of North America, Dr Aabed Meer and co-workers at the Stanford University at Palo Alto, California, have claimed that the risk of developing radiation-induced cancer from computer tomography (CT) may be lower than previously thought.
It is the first time in many years that a scientific study showed that the impact of CT on the incidence of cancer was less threatening! But the RSNA paper does not state that CT scans are risk free. The paper has not undergone any peer-reviewing as it was presented at the RSNA meeting, and not published in a peer-reviewed journal.
The study has certain other limitations. It estimates cancer risk to persons above 65 years. The views of learned bodies and professional associations on the study are yet to be published.
This study is statistically respectable as it included 10 million records of patients from 1998 to 2005. Based on Medicare database, they analyzed the distribution of CT scans, determined the radiation doses associated with them and estimated the associated cancer risk in a population of older adults. Medicare is a social insurance program administered by U.S.government, providing health insurance coverage to people who are aged 65 and over, or who meet other special criteria (Wikipedia).
The researchers included the data from two study groups; 5, 2767,230 records from 1998 through 2001 and 5,555,345 records from 2002 through 2005. They analyzed the number and types of CT scans that each patient received to find out the percentage of patients exposed to “low” radiation doses of 50 mSv to 100 mSv and “high” radiation doses in excess of 100 mSv (Sv is a unit of biologically significant dose and it involves the absorption of one joule per kg of radiation energy; mSv is a thousandth of a Sv).
They calculated the number of cancers that may be induced by using standard cancer risk models.
CT scans of the head numbered 25 per cent of the examinations in the first group and 30 per cent in the second. They found out that abdominal CT exposed patients to the greatest proportion (nearly 40 per cent) of doses in each group. The second and third largest sources of radiation were imaging of pelvis and chest
From 1998 to 2001, 42 per cent of the patients underwent CT scans; the corresponding percentage for 2002 to 2005 was 49. The researchers also found that the percentage of patients exposed to radiation doses in both the low and high ranges nearly doubled from the first group to the second. This was consistent with the increasing use of high speed CT in patient diagnosis and management.
They estimated the cancer incidence associated with exposure to radiation from CT to be 0.02 percent and 0.04 percent of the two groups respectively. The authors found a significantly lower risk of developing cancer from CT than the previous estimates of 1.5 per cent to 2 per cent of the population.
The study which gave higher numbers refers to a paper published by Drs David Brenner and Eric Hall, researchers in the Columbia University Medical Centre, New York in the New England Journal of Medicine (November 29, 2007)
This paper became very controversial. The American College of Radiology, the Radiological Society of North America and the Association of Physicists in Medicine reacted to the paper with predictable alacrity. These associations argued that the conclusions of the paper may scare away patients from clinically needed CTs.
The NEJM study got extensive media coverage as it focused attention on the overuse of CT. It was then estimated that one million children and 20 million adults in the USA undergo unnecessary CT scan procedures annually.
Medical radiation procedures must be carried out only if they are justified. Physicians must ensure that radiation doses are As Low As Reasonably Achievable (ALARA) without compromising clinical needs.

K.S. PARTHASARATHY
RAJA RAMANNA FELLOW DEPARTMENT OF ATOMIC ENERGY

( ksparth@yahoo.co.uk)

Published: November 4, 2010 16:50 IST | Updated: November 4, 2010 16:51 IST November 4, 2010

Radiation exposure: cancer risk in middle age

K.S. PARTHASARATHY

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AFP Stark reminder: The Atomic Bomb Dome is silhouetted in the sky beside the Peace Memorial Park in Hiroshima. Researchers reanalyzed the Japanese A- bomb survivor data and assumed two different pathways through which radiation exposure can lead to cancer.

Study of the data on A-bomb survivors continues to throw surprises.

An interesting analysis published in the Journal of the National Cancer Institute (25 October 2010) revealed that contrary to common assumptions, the risk of cancer associated with radiation exposure in middle age may not be lower than the risk associated with exposure at younger ages. The study is important as most of the diagnostic studies and occupational radiation exposures occur at middle age. However, if all radiation exposures are As Low As Reasonably Achievable (ALARA), there is no reason to worry.

Latent period

Children are more sensitive than adults to the effects of radiation as the cells in the body are dividing rapidly. Generally, cancer is induced after a latent period. Since children have longer life than adults, they have a greater chance of developing radiation-induced cancer than adults. Some data also suggest that, in general, the older a person is when exposed to radiation, the lower their risk of developing a radiation-induced cancer.

Recent analysis of the statistical evidence from long-term studies of atomic bomb survivors in Japan indicates that for radiation exposure after about age 30, the risk of developing radiation-induced cancer does not continue to decrease. This was not consistent with earlier studies.

Two pathways

Dr.David J. Brenner, at Columbia University in New York, and colleagues reanalyzed the Japanese A- bomb survivor data; they assumed two different pathways through which radiation exposure can lead to cancer.

Firstly, there may be the initiation of gene mutations that convert normal stem cells to premalignant cells that could eventually lead to cancer.

Second pathway

The second pathway assumes the existence of radiation induced promotion, or expansion, of the number of existing premalignant cells in the body. Researchers believe that the initiation effect is more likely to play a role in children than in adults; because cells initiated at an early age have a longer time available to proliferate and progress to cancer.

The promotion effect is more likely to be important for radiation exposures in middle age, because the adult body already contains larger numbers of premalignant cells.

Researchers developed a model based on these biological effects and applied it to the Japanese atomic bomb survivor data. The model reproduced the cancer risk patterns associated with age at radiation exposure observed in these survivors.

They applied the same model to predict cancer risks as a function of age in the U.S. population and found that the cancer risks predicted by the model were consistent with the data in the age range from about 30 to 60.

The authors argued that cancer risk after exposure in middle age may increase for some tumour types; this was contrary to what was known earlier.

Dr John D. Boice of the International Epidemiology Institute, Rockville, Md., and Vanderbilt University, Nashville, cautioned that there are uncertainties in generalizing the Japanese data to a U.S. population (Editorial in JNCI). According to him other data and other models contradict the results of this study.

Provocative hypotheses

He conceded that this biology-based model “raises provocative hypotheses and conclusions that, although preliminary, draw attention to the continued importance of low-dose radiation exposures in our society.”

Dr Brenner and colleagues concluded that overall, the weight of the epidemiological evidence suggests that for adult exposures, radiation risks do not generally decrease with increasing age at exposure, They noted that the mechanistic underpinning described here provides this conclusion with some biological plausibility.

Dr Brenner's papers may appear controversial; In 2003, he along with 14 eminent radio-biologists and epidemiologists concluded thus: “Given that it is supported by experimentally grounded, quantifiable, biophysical arguments, a linear extrapolation of cancer risks from intermediate to very low doses currently appears to be the most appropriate methodology.

This linearity assumption is not necessarily the most conservative approach, and it is likely that it will result in an underestimate of some radiation-induced cancer risks and an overestimate of others” (Proceedings of the National Academy of Sciences, 2003).

The JNCI paper throws fresh light on the topic.

K.S. PARTHASARATHY

Raja Ramanna Fellow, Department of Atomic Energy

(ksparth@yahoo.co.uk)

Keywords: radiation exposure, cancer, atomic bomb survivors

Radiation exposure and heart disease risk

On October 7, 2010, the UK Health Protection Agency published a report titled Circulatory Disease Risk prepared by its Advisory Group on Ionizing Radiation (AGIR). The report said that there is a clearly demonstrated risk for cardiac disease due to radiation exposures above 0.5Gy.

This has clear implications in radiation therapy. I brought the HPA report to the notice of a few medical physicists and radiation oncologists. The latter mostly belonged to the office bearers of the Association of Radiation Oncologists of India. I requested them to examine whether this report will help them to modify their working practices so that cancer patients may derive some benefits
                                                                                               

Dr K.S.Parthasarathy

Thursday, Oct 14, 2010

Radiation exposure and heart disease risk 

It would be appropriate to incorporate circulatory disease risks while estimating risks to individuals exposed to doses above 0.5 Gy

— Photo: V. Ganesan

The link: The expert group highlighted the need for further research to better understand the link between radiation exposure and circulatory disease.

The study of biological and medical effects of ionizing radiation continues to be enigmatic. After over ten decades of intensive and extensive studies, specialists concluded that high doses of radiation may cause cancer in the exposed individual.
At low doses there is some uncertainty; however in the field of radiation protection, specialists assume that radiation doses at all levels are carcinogenic.
Evidence on links
Evidence on links between radiation exposure and non cancer diseases such as heart disease has emerged more recently.
For many years, scientists suspected these links. On October 7, 2010, the UK Health Protection Agency's (HPA) Advisory Group on Ionizing Radiation (AGIR) published a report titled “Circulatory Disease Risk”, reviewing the recently published epidemiological studies and experimental work on the risks and potential causes of circulatory diseases following exposures to ionizing radiation.
The report urged the clinicians who use medical radiation procedures in diagnosis and therapy to examine their working practices.
AGIR recommended that where possible they should keep the radiation doses to the brain and heart of the patients as low as possible while maintaining essential medical benefits (HPA Release, October 7, 2010).
The expert group also highlighted the need for further research to better understand the link between radiation exposure and circulatory disease.
The AGIR concluded that radiation exposure to the heart and circulatory system can occur in several contexts. For instance, the circulatory system of the entire population is exposed to a part of the natural back ground radiation. These are low levels.
“Radiation workers may receive higher doses and those receiving medical diagnostics, some medical interventional radiological procedures and, particularly, radiotherapy may receive doses to the circulatory system, or parts of it, up to the level of several gray (absorbed dose)”, the specialist group added
(gray-Gy- is a unit of absorbed dose; a tissue is said to receive one gray of dose, when the energy due to ionizing radiation absorbed by it is one joule per kilograme. AGIR defined doses thus: Very high – doses above 15 Gy; High – doses of 5–15 Gy; Medium –doses of 0.5–5 Gy; Low – doses below 0.5 Gy)
“Even small relative risks due to radiation could have a major impact…….. as circulatory diseases are already common in the population”, the specialists cautioned. For instance, circulatory diseases are common in Western populations and are the main cause of death in the UK, accounting for some 193,000, or 34 per cent, of deaths each year.
AGIR noted that evidence from radiotherapy follow-up studies and from experimental animal models indicates that irradiation at high and very high doses increases circulatory disease risk. But the use of cardio-toxic drugs in chemotherapy complicates the precise estimation of risk.
Clinicians have detected a statistically significant increase in the risk of certain circulatory diseases (notably, stroke, heart disease and specifically ischemic heart disease) at low and moderate dose (below 5 Gy) epidemiological studies, notably the atomic bomb survivor studies and nuclear worker studies.
While heterogeneity between the studies is considerable, statistically significant excess risk can be detected at around 0.5 Gy; contributory risk factors such as cigarette smoking, diet and alcohol consumption may confound these studies.
Emergence unlikely
Convincingly strong association with, circulatory disease below doses of 0.5 Gy is considered to be very unlikely to emerge from human population studies in the near future. Insights from mechanistic experimental studies may eventually show whether cardiac diseases may be caused by low radiation doses.
According to AGIR, there is currently little evidence to justify the inclusion of circulatory disease while calculating radiation risk at doses of 0.5 Gy and below. This is a pointer towards more research. Radiation protection specialists can breathe easy.
AGIR concluded that it would be appropriate to incorporate circulatory disease risks when we estimate health risks to individuals exposed to doses above 0.5 Gy. This is a clear message to radiation oncologists. Dedicated use of Intensity Modulated Radiotherapy (IMRT), if available, may be useful.
The Association of Radiation Oncologists of India may review the HPA report and examine how best they may modify their practices wherever appropriate, to give maximum benefits to their patients.

K. S. PARTHASARATHY

Raja Ramanna Fellow, Department of Atomic Energy
( ksparth@yahoo.co.uk)

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
________________________________________
Back Sci Tech

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
© Copyright 2000 - 2009 The Hindu

New Health Studies on A-bomb Survivors

Published on: August 28, 2010 - 23:04

More in:

• 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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Findings on artery plaque

                                            

Tuesday 10 August 2010

Medical Research
Findings on artery plaque

Haim Shmilovich and his fellow researchers from Heart Institute, Cedars-Sinai Medical Centre, Los Angeles, California found that, besides the degree of blockage, the composition of the plaque causing the blockage has significant impact on blood flow through coronary artery, writes K S Parthasarathy

If a person is diagnosed as suffering from heart disease, the current medical practice is to carry out an invasive procedure such as angioplasty or stent-placement or open heart surgery as appropriate. A study presented at the 57th Annual Meeting of the Society of Nuclear Medicine in June at Salt Lake City, USA is challenging this practice.

People with similarly blocked arteries can experience vastly different symptoms. Nobody knows why.

Dr Haim Shmilovich and his fellow researchers from Heart Institute, Cedars-Sinai Medical Centre, Los Angeles, California found that, besides the degree of blockage, the composition of the plaque causing the blockage has significant impact on blood flow through coronary artery. May be this is why two people with similarly blocked arteries can experience vastly different symptoms.

According to Dr Mason W Freeman, Associate Professor, Harvard Medical School coronary artery disease (CAD) begins when plaques build up in the arteries.

Plaque deposit hardens later

He vividly described the process. Initially, the plaque deposit may be soft and mushy; later it hardens, narrowing the artery. Blood flow to the heart decreases; at the beginning, this reduction is not severe enough to compromise heart muscle function or to produce any symptom.

Later on, the plaque may enlarge further reducing the blood flow. After a critical point, the heart muscle no longer gets adequate oxygen delivery when it is working vigorously. A prolonged or complete interruption will kill myocardial cells and cause a heart attack.
The plaques are not homogenous. They contain fat and other substances including calcium. Plaques vary in size. Even very young persons may have early stage plaques. When plaques cause blockade of the arteries, symptoms develop .When the blockade is 70% or more physicians carry out invasive procedures to reduce symptoms and potentially to prevent heart attacks. How can we determine the composition of the tiny deposits of fat in the blood vessel of a few millimetres diameter deep inside a living person? Researchers use coronary CT angiography (CCTA) for this and to find the degree of blockage it causes.

Use of an intravenous dye

The coronary CT angiography uses an intravenous dye which contains iodine and CT scanning to image the coronary arteries. Physicians measure the relative blood flow to different regions of the heart by myocardial perfusion imaging (MPI). During myocardial perfusion imaging, the physician administers a radio-pharmaceutical intravenously to depict the distribution of blood flow nourishing the myocardium- the middle of the three layers forming the wall of the heart.

Perfusion imaging identifies areas of reduced myocardial blood flow associated with ischemia or scar. Physicians can assess the relative regional distribution of perfusion at rest, cardiovascular stress, or both. They also perform imaging during chest pain of unknown etiology, such as in the coronary care unit or emergency department.

They found that clinicians can more accurately determine a patient’s risk of reduced blood flow to the heart muscle by identifying three plaque characteristics: the presence of a fatty core, signs of spotty calcifications and enlargement of the arterial wall from “positive remodelling”, which means that the body has responded to arterial damage by altering the structure of the artery. Researchers noted that either individually or combined, the presence of these characteristics can predict reduced blood flow to the heart muscle, which could lead to symptoms including heart attack.

They imaged 34 patients without known coronary artery disease using CCTA and MPI to determine the presence of adverse plaque characteristic and blood flow. All patients had severe (70 to 89 per cent) blockage in the beginning or middle section of a major coronary artery on CCTA.

A third-party expert evaluated adverse plaque characteristics on CCTA; an automated computer -based analysis carried out the myocardial perfusion imaging.

When imaged with MPI, over 38 per cent had significantly limited blood flow to the heart muscle.

In the arteries with plaques with a fatty core, significant ischemia (condition in which blood flow and hence oxygen supply is reduced) of the heart muscle occurred at a much higher and statistically significant frequency (80 per cent) than those without fatty core (21per cent).

When specialists found multiple adverse plaque characteristics in a plaque, that was associated with higher degrees of significant ischemia.

Findings could redefine treatment

The researchers claimed that if they can determine certain characteristics of the coronary artery plaque, they can predict whether a patient’s symptoms are due to limitation of blood flow to the heart.

They believe that with more studies, their findings may change treatment planning for patients with severe but stable coronary artery disease by helping them determine which patients could be treated just as effectively with medications and life style changes, thereby avoiding unnecessary invasive angioplasty and bypass surgery. The study is promising. A major problem with all medical imaging modalities is that the technology advances with unbelievably astonishing speed; the clinical use lags disappointingly behind.

(The writer is Raja Ramanna Fellow, Department of Atomic Energy.)

Laser pointers may damage vision

THE TRIBUNE


SCIENCE & TECHNOLOGY
Friday, August 6, 2010, Chandigarh, India


Laser pointers may damage vision
K.S. Parthasarathy



AS Dr.Timothy B L Ho, Firmley Park Hospital NHS Foundation Trust, Surrey, UK entered his house one evening, his seven year old son flashed a laser pointer on his face. The eye injury, he suffered, was not apparent immediately.
Four days later, he developed an area of partial alteration of his field of vision His son found the device, a gift from a drug company, on his father’s desk. Laser pointers which are common place now can damage vision if handled carelessly.
“My vision took several months to recover and initially I was very worried”, Dr Ho wrote in The British Medical Journal, (BMJ, 29 June 2010), when Drs Ziahosseini, Doris and Turner published in the BMJ, a laser injury case suffered by a teenager.
He bought a green diode laser pointer over the internet and shone the laser beam into his eyes while playing with it. He had no previous medical or ophthalmic problems. Tests confirmed disturbance of his retinal pigment epithelium; it took two months to improve his clearness of vision.
In yet another instance, while on the school bus, a friend attempted to determine whether a laser pointer would cause pupillary constriction (Arch Ophthalmol, Nov 1999). She made an 11 year old girl to stare at an activated laser pointer for several multi-second exposures with the right eye. The victim immediately noted decreased vision. It took many months to recover her vision; long term effects of the injury are unknown.
Retinal injuries from lasers may be caused by ablative, thermal or photochemical mechanisms. These depend on power, wavelength, exposure time and size of the pupil (BMJ, 27 May 2010). Normally, the adverse impact may be transient; they may disturb the retina and the interconnecting layers and may induce clinical conditions causing loss of sight later.
Laser pointers costing a few dollars are available in curio shops, electronic stores or office supply shops. You may buy them directly or through mail order or by placing orders with internet outlets. Children may use them as toys.
Most laser pointers used while presenting lectures operate in the visible light region of wavelengths between 600 to 670 nanometre (one-thousandth of a millionth of a metre, nm). They are low powered, battery operated, hand-held devices and are cheaper than those operating at green light of wavelength 532 nm.
The response of the eye depends on wavelength with a peak at about 550nm. It decreases as either end of the spectrum is reached. If laser pointers are compared at the wave lengths of 670 nm, 635 nm and 532 nm at the same power level, the brightness as eye perceives it will be nearly in the ratios of 1:10:30.When the laser beam is closer to the eye’s peak response, it can produce adequate visual stimulus at lower power levels.
If you want to buy a laser pointer choose only one that is labelled Class II and operates with a wavelength between 630 nm and 680 nm. Maximum output should be less than 5 milliwatts.
Before you use a laser pointer, read the caution or danger sticker carefully. Never point the laser at another person. Do not point a laser pointer at mirror-like surfaces. A reflected beam can act like a direct beam on the eye. Never look directly at the laser beam. Never view a laser beam using a binoculars or a microscope.
Lastly, you must not gift a laser pointer to a child. You may regret later. Laser pointers are not toys.
The writer is Raja Ramanna Fellow, Department of Atomic Energy

No genetic effects in children of A-bomb survivors

THE HINDU

S & T
Published: August 5, 2010 03:48 IST | Updated: August 5, 2010 03:58 IST August 5, 2010
No genetic effects in children of A-bomb survivors
K. S. PARTHASARATHY






AP SEVERAL STUDIES: In the 1950 Japanese national census nearly 2,80,000 persons claimed that they were exposed to radiation. Several studies have been carried out on the survivors. Photo: AP
On August 6, 1945, the U.S. dropped an atom bomb on Hiroshima. Nagasaki was bombed three days later.
In the 1950 Japanese national census nearly 280,000 persons claimed that they were exposed to radiation. Initially, the Atomic Bomb Casualty Commission and from 1975, Radiation Effects Research Foundation (RERF), carried out several studies on the survivors.
Research programmes
The research programmes covered Life Span Study (LSS), Adult Health Study, study of the Children of Atomic-bomb Survivors (F{-1}) and the evaluation of the lifetime health experience of a specially exposed population, namely those in utero at the time of the bombings.
Other areas covered included immunology, radiation biology, molecular epidemiology, cytogenetics, statistics and A-bomb dosimetry.
RERF researchers and other scientists studied the interaction with radiation and smoking.
Radiation increased the risk of lung cancer among the survivors. Among 105,404 subjects of the LSS, researchers identified 1803 primary lung cancer cases for the period 1958-1999.
They used individual smoking history information and the latest radiation dose estimates to investigate the combined effects of radiation and smoking on lung cancer rates.
Lung cancer risks
Relative to never-smokers, lung cancer risks increased with the amount and duration of smoking and decreased with time since quitting smoking at any level of radiation exposure (Radiation Research, 174, 2010).
The excess risk increased rapidly with smoking intensity up to about 10 cigarettes per day, but additive or sub-additive for heavy smokers smoking a pack or more per day, with little indication of any radiation-associated excess risk
The authors concluded that the joint effect of smoking and radiation on lung cancer in the LSS is dependent on smoking intensity and is best described by the generalized interaction model rather than a simple additive or multiplicative models
Fatty liver predicts ischemic heart disease or heart disease due to reduced blood supply to the heart.
Fatty liver predictors
The researchers at RERF observed the incidence and predictors of fatty liver by examining 1635 survivors of Nagasaki A-bomb every two years through 2007 (mean follow up for 11.6 y) by abdominal ultrasonography.
The subjects were without fatty liver at base line (November 1990 through 1992). The researchers diagnosed 323 new fatty liver cases.
The average incidence was 19.9 cases in 1000 person years peaking in the sixth decade of life (Hypertension Research April 2010).
After controlling for age, sex, and smoking and drinking habits, obesity, hypertriglyceridemia (large levels of tryglicerides) and hypertension were predictive of fatty liver.
All variables included
When all variables are included, obesity, hypertriglyceridemia and hypertension remained predictive.
Scientists have not observed genetic effects in the children of A-bomb survivors.
To evaluate the genetic effects of A-bomb radiation, RERF researchers examined mutations at specific loci in the chromosomes of exposed families (father-mother-offspring, mostly uni-parental exposures) and control families. The mutation rates observed were not statistically significant.
That radiation exposure causes thyroid cancer is an established fact.
But we do not know the radiation effects on papillary micro carcinoma (PMC) of the thyroid, a common sub-clinical thyroid malignancy.
RERF researchers identified PMCs in a subset of 7659 subjects after reviewing their pathology and evaluating the histological features of the tumors.
Papillary thyroid cancer
From 1958 to 1995, they detected 458 PMCs among 313 study subjects; most of them exhibited pathologic features of papillary thyroid cancers.
A significant radiation-dose response was found for the prevalence of PMCs with the excess risk observed primarily among women.
Exposure to low-to-moderate doses of ionizing radiation appears to increase the risk of thyroid PMCs, even when exposure occurs during adulthood (Cancer, 2010).
Raja Ramanna Fellow with the Department of Atomic Energy
(ksparth@yahoo.co.uk)
Keywords: Hiroshima bombing, genetic effects
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