Shielding is one of the most critical aspects while installing any diagnostic radiology. If you don’t follow the guidelines properly during the shielding method, then you will end up in the zone of non-compliance. But this is not it, as in addition to breaking the law, you can severely hurt the person undergoing the test, and improper shielding puts the operator’s life at risk too. This is the main reason why so much focus is given to different aspects of shielding during diagnostic radiology installation, replacement, or shifting.
The structural design for diagnostic radiology installation is based on the National Council on Radiation Protection and Measurements. If you want to be more specific, you can refer to Report No.49 . These measurement guidelines have been acting as the primary guidance for performing structural shielding for a very long period, or we can say since its inception.
But because of the evolutionary nature of technology and significant changes in how technology is used in diagnostic radiology, Report No.49 has become outdated. Many technological advancements have made Report No.49 obsolete, and some of these technical introductions are mammography, tomography done through computers, and even digital imaging.
In addition to this, there have been many changes brought to the imaging techniques that have abandoned the old practices. For example, screen intensifying and films have reduced exposure to radiation while enhancing the quality of the image. Check out radiation protective clothing manufacturers.
Because of all these changes, we are now using a revised radiation shielding methodology mentioned in Report.49. And the best part about this revised methodology is that it allows the designers to work on the shielding to identify economic and completely safe obstacles in diagnostic radiation settings while considering the actual workload and new technologies.
All these changes brought into the Report.49 can be applied to both the existing facilities and the new facilities. This also means substituting new parts for older ones in existing structural design becomes completely unavoidable.
Theoretical background and the methods used.
The installation of diagnostic X-ray imaging includes two radiations in that particular environment, and these two radiations are secondary radiation and primary radiation. Now, it becomes necessary to understand the basics of both primary and secondary radiation.
Primary radiation is any radiation emitted directly from the X-ray source to the primary barrier. While on the other side, secondary radiation is any radiation that scatters from the person undergoing the test or from any nearby object, in addition to the leakage radiation from the tube of the X-ray machine. There are various factors on which the amount of secondary and primary radiation depends, and some of those factors are;
- The total amount of radiation coming from the source
- The total distance from the source to the target area
- The total time that a person occupied
The radiation shielding calculation
One of the main things to understand about nuclear medicine shielding calculationsis the entire concept of this calculation that is entirely dependent upon the goals of the shielding design. And this is where all the proposed limits for the design are brought down by a factor of 10 for highly controlled areas and uncontrolled areas, and it is brought down by a factor of 5. If you wonder whether such reduction in the doses is mentioned, you should read NCRP Report 116 .
In addition to the shielding design goal, the method used to do nuclear medicine shielding calculations also depends on the distance to occupied areas. Such a type of specification has been mentioned in both NCRP Report 147 and 49.
Talking about the occupancy factor, according to the report, this particular factor is the average fraction of time a maximally exposed person is present. But because of some alterations in the revised shielding calculation methodology in the radiology department.
If you go by the NCRP Report 49, you get to know a unity value in the case of total occupancy and a minimum value of 1/6. But according to Report 147, the minimum value has been raised to a more realistic level of 1/40, and the total occupancy has been kept to the importance of unity.
It would help if you always had a qualified expert like XRCT Limited to design and use the shielding materials effectively. The expert will also be required for evaluation or nuclear medicine shielding calculations of the results. But you must note that both the time, effort, and cost involved in radiation shielding design must be taken seriously; otherwise, you have to deal with complications.