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.

Some terms explained - radiological protection

As per the ICRP (2007), the threshold dose is defined as the “estimated dose for incidence (EDI) of a specific observable effect in 1% of individuals exposed to radiation”. Tolerance dose is used to denote the maximum amount of radiation a tissue can withstand without developing clinical signs of injury in more than a few percents of individuals. “Clinically significant” term is used to denote the level of severity which is detectable and is associated with noticeable symptoms or sign of impairment of function.

“Cell death” term is used to denote the loss of the cell’s reproductive integrity, without necessarily losing other cell functions. “Cell survival” can be defined as the ability of a cell to proliferate indefinitely to form a colony of its daughter cells.

Humans can tolerate a higher total dose of chronic, low-dose-rate irradiation than an acute single dose. Chronic exposure provides enough time to repair a sub-lethal injury to the cell. Injury to the cell is repaired by the inherent repair mechanism in the body. In addition to this, there are “adaptive reactions” at the cellular, organ, and whole-body level. That is the reason why under chronic exposure situations, a higher total dose is required to develop clinical signs of cell injury as compared to the acute single dose.

It is desirable that the dose limit (100 mSv in 5 years) for occupational exposures is permitted under chronic exposure conditions.  

Probably, the first Code of Practice for Protection of X-ray Operators - 1915

Probably, the first code of practice, a set of 7 radiation protection rules, was issued by British Roentgen Society in November 1915 (The image is reproduced in Bull. of Radiation Protection, Vol. 18 (4), 1995, p. 23).

Recommendations for the Protection of X-ray Operators

The harmful effects produced by X-rays are cumulative and do not generally appear until some weeks or months after the damage has been done. It is to be noted that X-rays of any degree of hardness are capable of producing ill effects, although it is commonly supposed that soft X-rays only are harmful.

It is undesirable that any X-ray treatment should be carried out except under the direction of a qualified medical practitioner experienced in X-ray work.

All X-ray tubes must be provided, when in use, with a protecting shield or cover which prevents the access of the rays to the operators and which encloses the tube, leaving an adjustable opening only sufficiently large to allow the passage of a sheaf of rays of the size necessary for the work in hand. Even with this shielding, the operator may not be completely protected in all cases (e.g., especially in screen work), and the use of movable screens, gloves and aprons is recommended.

Operators should be warned that shields obtainable commercially are often ineffective and test of their opacity should be made.

Whenever possible the cubicle system should be used for X-ray treatment and the operator should be able to make all adjustments from a protected space.

When screen examination is required it is essential that the screen should be covered with thick lead glass of proved opacity and that the screen should be independently supported and not held in the hands of the operator. If the hands are so used they should be properly protected.

The hand or any portion of the body of the operator should never be used to test the hardness or quality of the X-ray tube; any simple form of penetrometer can be easily arranged for this purpose. #radiation #X-rays #radiationsafety #radiology #regulation #healthphysicist #radiologicalprotection