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Tuesday, May 11, 2021

Extracts from the reference book: Radiological Protection and Safety - Preface

Radiation is ubiquitous. All humans are exposed to natural background radiation consisting of cosmic radiation, cosmogenic radionuclides and terrestrial radiation from the radioactive materials present in the earth. In addition to this, humans are also exposed to artificial or man-made radiation sources. In all, globally on an average, the annual radiation dose due to these sources works out to be around 2.4 mSv. The levels of natural radionuclides are enhanced significantly in situations where the materials are processed in industrial scale to obtain useful materials such as uranium, thorium, rare-earth elements, etc.   

This reference book entitled “Radiological Protection and Safety – A Practitioner’s Guide” is designed to guide persons involved or related to radiological protection, i.e., Health physicists (HPs), Radiological Safety Officers (RSOs) and Medial health physicists who, by and large serve as a link between the facility or installation management and the regulators, to ensure radiological protection and safety. This resource book is also useful to researchers, trainers, students, the radiological and nuclear facility operators, the regulators and personnel undergoing training in fields dealing with radiation and radioisotopes. Training of the personnel in radiological protection and safety forms the focus of radiation protection programmes and creates an awareness to remove inherent radiophobia or fear of radiation amongst educated and other members of the public. This is important in the current scenario of potential of nuclear terrorism world-wide. 

Occupational workers are those who are exposed to radiation during the course of their work.  The concepts of radiological protection, radiation protection standards, regulations as well as the exposure control techniques are changing over time. This reference book, organized in about 350 pages and in 19 chapters, covers radiological protection and safety aspects in life cycle of nuclear fuel cycle facilities. It also covers current status of the issues and topics of concern in the wide variety of applications of radiation and radioisotopes, particularly technological developments in medicine and industry. The occupational risk of harm needs to be acceptable in comparison with the risks in other industries which are considered as safe. 

Radiation protection is a multi-disciplinary subject. The ICRP system of radiological protection is applicable to all facilities and activities involving radiation sources or radioactive materials with potential for occupational exposures. In general, from a regulatory perspective, the nuclear fuel cycle operations, i.e., starting with mining of the natural uranium, milling, reactor fuel production, the fuel fabrication, nuclear reactor operation, the spent-fuel reprocessing and the radioactive waste management, are well covered and generally under the regulatory control of the government. However, the use of radiation and radioisotopes are being increasingly used in public domain in medicine and industry posing newer challenges. There are numerous techniques in medical diagnosis and therapy where patients are exposed to radiation for medical diagnosis and therapy. However, these techniques also occupationally expose the physicians, the radiologists, the paramedical staff, the technicians, the care takers and the public at large, to the radiation.

In addition to the peaceful uses of radiation, there is a threat of terror organizations using orphan, stolen or disused radiation sources to harm civilians and others by malicious use of the sources in many forms such as Radiological Dispersal Devices (RDDs). Nuclear and radiological emergency is considered important and is separately covered in the chapter on radiological safety in emergency exposure situations. The types of emergency situations, the preparedness and response are discussed in the book with latest references. Security of the radiation sources and radioactive materials is currently a concern, which is being addressed by international and national bodies. Relevant references are provided on the subject for the information of all concerned.

The UNSCEAR periodically provides comprehensive data on levels and effects of radiation exposures in different applications of radiation and radioisotopes. International Commission on Radiological Protection (ICRP) reviews the inputs from various sources, including epidemiological studies on the exposure of groups of population and experimental findings and provides basic recommendations periodically. Recent Most recommendations are published in ICRP-103, 2007. 

Wherever possible, references are provided for the numbers used. As always happen in the health physics profession, informed judgements/thumb rules, based on decades of operational radiation protection experience have provided adequate level of safety required in the profession. As per the educationist David A. Kolb, learning is a process whereby knowledge is created through the transformation of experience.

In order to contain the size of the reference book to be “acceptable” for the readers, brevity has been an important consideration to include most of the topics of relevance to radiological protection and safety. References of radiological significance in the topics are provided at the end of each chapter, to be pursued by the reader for further details.

The reference book will be useful to all stakeholders in the nuclear industry who would like to refer to one book to know about all aspects of radiological safety in the application of radiation and radiation sources for the benefit of people. I dedicate this book to the radiation protection community, who work tirelessly to protect people and the environment from the harmful effects of radiation exposures. 

Monday, March 15, 2021

The updated document (ICRP-146, 2020) for mitigating radiological consequences of nuclear accident

There is an updated latest ICRP document entitled Radiological Protection of people and the environment in the event of a large nuclear accident published by the ICRP as the Publication No. 146 (2020). The document is the updated versions of ICRP – 109 and ICRP- 111, which cover emergency exposure situations. The new document draws experience of the Chernobyl and Fukushima accidents.

The early and intermediate phases of accidents are considered as Emergency exposure situations and the long-term phase is considered as existing exposure situations (ICRP-103). Mitigating the radiological consequences on the humans and the environment are achieved by the justification and optimization principles as discussed in the ICRP. A set of reference levels are recommended for protection of general population, and for the protection of all concerned in the mitigation process. The concerned authorities at national and local level, are responsible for implementing radiation monitoring and surveillance programs. The authorities also are responsible to involve all the stakeholders in the emergency preparedness process and management of the successive phases of the accident.  

Tuesday, March 2, 2021

Posts related with the PREFACE of the reference book Radiological Protection and safety (Sep. 2019)

Radiation is ubiquitous. All humans are exposed to natural background radiation consisting of cosmic radiation, cosmogenic radionuclides and radiation from the radioactive materials present in the earth. In addition to this, humans are also exposed to artificial or man-made radiation sources. In all, globally on an average, the annual radiation dose due to these sources works out to be around 2.4 mSv. The levels of natural radionuclides are enhanced significantly in situations where the materials are processed in industrial scale to obtain useful materials such as uranium, thorium, rare-earth elements, etc.

Thursday, February 4, 2021

Radiological protection in nuclear medicine


In In nuclear medicine, “radiopharmaceutical” are used as source of ionizing radiation for medical diagnosis and therapy. Radiopharmaceuticals are biologically active molecules labeled by short-lived radionuclides. The actual mass of radioactive material in any radiopharmaceutical is too trivial to cause any toxic effect. The radiopharmaceuticals are administered into the human body. The image of the radionuclide distribution within the body/organ of interest as a function of time is studied. Radiopharmaceuticals are increasingly used for the treatment of various cancers with novel radionuclides, compounds, tracer molecules, and administration techniques.

Before such procedures involving radionuclides are performed, the physician is able to quantify the radiation dose delivered by the radionuclide to the tumour and the normal tissues. It is essential that the doses are optimized for the patient protection. Considerations need to be given to minimize the staff exposures through proper equipment design, adequate shielding and handling of sources, use of personal protective equipment, etc. Medical physicists/RSO provide specific radiological protection guidance to patients and carers.

 A recent ICRP publication (ICRP-140, 2019) provides all aspects of radiological protection in therapy with radiopharmaceuticals


Thursday, January 7, 2021

Book Review (


The review of the reference book Radiological Protection and Safety – A Practitioner’s Guide is published in the quarterly journal Radiation Protection and Environment (RPE), Vol. 42(3)/2019/119-121. The journal is being published by the Indian Association for Radiation Protection (IARP). Readers are requested to go through the review for more information about the book using the link:

 Dr. D.D. Rao, the Editor of the journal concludes: “In my view, author has put in all his professional experience spanning over four decades in preparing this reference book, particularly in chapters 6-10, and chapters 14-16. I sincerely hope that professionals, students, teachers and researchers, or whosoever refer this book, will get immensely benefited from the contents of this reference book”.


Monday, December 14, 2020

Protection against Radon

Radon-222 being gaseous inert radionuclides, inhalation of the radon gas is not as hazardous as its short-lived, alpha emitting daughter products, with different half-lives. While inhaled radon gas is exhaled out, inhaled particulate radon daughters get deposited in the respiratory tract and continue to give dose to the lung tissues until they fully decay. In the meantime, some amount of the deposited daughter products, being highly soluble in body fluids (like blood) and get transported to different organs/tissues and finally get excreted through urine. Hence, the inhalation dose (internal dose) received by the lung and other organs is much higher in case of inhalation of radon daughters than the radon gas alone.

In uranium mines, inhalation of radon daughter is a major health hazard. There is a relation between the exposure to radon daughters and the lung cancer incidents amongst the mine workers. Protection standards are developed based on the exposure data.

The main strategy to protect the workers is to use proper respiratory protection to filter out the daughter products; provide adequate once-through ventilation in the work areas to dilute and disperse the radon and radon daughter activity, and monitor the activity levels in the air continuously.

The protection standards for radon, thoron and their daughter products are discussed in more detail in an Editorial by Dr. Pushparaja: Radon in dwellings and workplaces: An update on current regulations, Radiation Protection and Environment Journal, Vol. 42 (1&2), 2019, p. 1-4.

Tuesday, December 1, 2020 is updated!

Use of radiation and radiation sources in public domain is exponentially on the rise from medical and industrial applications. Security of the radiation sources is important since any lost, stolen and misplaced radiation source, or source in the hands of miscreants can create an emergency-like situation. It is the responsibility of one and all of us to be aware of the consequences, and means to protect ourselves, our near and dear ones, and protect others.  

However, there is not adequate awareness about the radiation utilization, and radiation protection and safety amongst the public in general, and people who take the benefits from the applications. Radiation protection is not taught in colleges. In order to create a general awareness amongst the people, a website is created and recently updated. The free website is:


Request everyone to go through the site, and give comments if any. They may also spread this information to create the awareness about radiation and its benefits.