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

 

Book Review (http://notionpress.com/read/radiological-protection-and-safety)

 

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: 

https://www.rpe.org.in/text.asp?2019/42/3/119/270444

 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”.

 

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.

www.radsafetyinfo.com 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: www.radsafetyinfo.com

 

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. 

Ignorant members of public - About ionizing radiation

Let us frankly expose the TRUTH – Common man (person) including illiterate, semi-illiterate, and so-called literate or educated, hardly know anything about ionizing radiation. They only know that radiation is very harmful, so many thousands have died in the explosions of atom bombs in Japan; exposed person will lose hair and become impotent, etc etc. How we are going to explain all the benefits we talking about to such a large percentage, may be more than 90% of the population who are lacking an understanding of elementary radiation physics, mathematics, biology and medicine?

Communication is the key. All the practitioners of applications of radiation and radiological protection should focus on ways and means to create awareness amongst the people about radiation, benefits of low level exposures, medical uses in health-care and food preservation, some health effects at high levels of exposures, and how safely the radioactive waste is managed by concerned experts. We should use mass media communication systems and school/college syllabus to maximum possible extent. Desist from use of words, like probability, ALARA and risk analysis when communicating with members of the public.

Radiological protection in medicine

Use of radiation in medicine has been increasing around the world in the recent past for diagnosis and therapy. The fluoroscopically guided interventional procedures are minimally invasive and used as an alternative to conventional surgery, resulting in reduced patient morbidity and mortality.

Radiation doses to patients from fluoroscopically guided interventional procedures may be high enough to cause skin injuries and increased probability of developing cancer in future years. There is also a risk to staff members of deterministic effects such as cataract formation. Optimization of the patient dose is important.

Although many fluoroscopically guided interventional procedures are conducted in radiology departments, they are increasingly performed by non-radiologists in other areas of the hospital, such as hybrid operating rooms. It is important to ensure that adequate radiation protection training and support services like radiation monitoring are provided to staff members involved in fluoroscopically guided interventional procedures. Radiological protection of the staff members need to be an important consideration while developing new interventional procedures.   

Radioisotope Generator

Radionuclide generator can supply a medical radionuclide in very high specific activity, often a very important concern in modern radiopharmaceutical formulation. It can also be designed to supply the radionuclide in a chemical form that is practically useful in the pharmacy or clinic.

Radionuclide generators have played a major role in the diagnostic nuclear medicine. Various radionuclide generators are in clinical use, particularly, Mo-99/Tc-99m generator. The major part of the radioactive generated in a nuclear medicine laboratory is of Tc-99m, followed by and Ge-68/Ga-68. An account of the available for clinical use and the regulatory challenges are discussed in an article by Knapp, Jr., and Pillai, et al, 2014). In nuclear medicine procedures, target-specific radiopharmaceutical is introduced to the body, the emissions from the radionuclides are detected and transformed into images which can be seen by the expert doctors to facilitate diagnosis. Radionuclides such as Tc-99m, I-131, I-125, P-32, Lu-177, F-18 are produced and used in the medical applications. Radiological protection of the staff is controlled and kept as low as reasonably achievable. Patient dose is optimised for protection of the patient.