Use of leaded aprons during Industrial Radiography? (Keep an eye on AI!)
Published: May 08, 2026
Prelim
The idea for this blog article stems from some recent posts seen on LinkedIn. We are increasingly frustrated by the obvious use of AI (artificial intelligence) developed images to depict training or informational resource, but which to the experienced eye are clearly not what the creator (or AI?) intended. We have become more critical of late and left comments which are intended to be constructive. It is always useful to turn such situations into a learning point, and this is the purpose of this article.
One LinkedIn post used the following image to depict Radiation Protection Officer (RPO) duties in industrial radiography. This image has been obtained via an internet image search rather than lifting from the original post. Having considered the intention of this post (education, not criticism), the creator (i.e. the person who used AI) has not been referenced. If they are reading this blog article and want to be credited then please get in touch and we will pop your name / LinkedIn link below the image.
LinkedIn post image on RPO duties in industrial radiography
What does AI say?
As an experiment this image was fed into a few AI engines (Grok, ChatGPT, Gemini etc) and they were asked to identify what was wrong with the image. To give some assistance AI was told that it was a radiation safety related post for industrial radiography. Here are some examples of what AI came up with.
- The trefoil appears on helmets and handheld devices (you don't see this usually on PPE).
- Dose rate monitor usage looks unrealistic (looks posed, not being used correctly).
- Work area control is oversimplified (no controlled areas / exclusion zones obvious, just cones).
- Monitoring workers – incorrect application (one worker appears to be frisked for contamination rather than area dose rate monitoring).
- Radiography devices (?) are not realistic (no projectors, guide tubes, x-ray tubes or obvious collimators).
All of the above examples are reasonable spots - in fact AI did a little better than expected (but recall that AI was told this was industrial radiography, so it had a helping hand).
However, a lot of the suggestions above are probably based on the items in the image not being rendered in sufficient detail. The radiography device shown is clearly AI generated - a hybrid of a source projector / x-ray tube / collimator.
However, none of the AI tests picked out the two key issues that are wrong with this image (and recall the creator stated that AI was used to render the image).
What is fundamentally wrong with this industrial radiography image?
The two aspects of the image that are obviously wrong are as follows:
- Everyone appears to be wearing leaded aprons / PPE of the type you might find in the diagnostic x-ray department of your local hospital.
- If that were bad enough, from our interpretation of the image, it looks like dosimetry (passive or active) is being worn on the outside of this leaded PPE? This is not standard practice.
One popular AI engine (Grok) was asked to comment on the dosimetry specifically and stated that:
- Grok: The primary dosimeter (whole-body badge, TLD, or electronic personal dosimeter) should typically be worn outside any lead apron at collar or chest level. This measures the actual exposure to unprotected parts of the body (especially head, eyes, and thyroid) and provides a conservative estimate for regulatory compliance.
This is not how whole body (HP10) dosimetry works. Contrary to what some might think (including it appears AI), dosimetry is not about measuring the worse case scenario (a.k.a conservative estimate), it is designed to measure a best estimate of the dosimetric quantity required. In the case of whole body dosimetry (TLD, film badge or active dosimeter), you want to measure underneath (inside) the PPE. A second dosimeter can sometimes be placed outside the PPE in order to determine the performance of the PPE itself (or make estimates of cases where the PPE was not used when it was supposed to be). Furthermore, it is possible to use additional dosimeters to measure thyroid or eye (lens) exposure specifically. But these secondary dosimeters if used are a diversion, primary dosimeters placed outside the PPE, as depicted in the info graphic, is just wrong.
Enough of dosimetry for now - since the bigger issue is the apparent use of leaded PPE in industrial radiography. When the content creator was politely questioned on this point they replied with words to the effect of: ' ... focus was only on presenting the technical aspects of the Radiation Protection Officer’s role in industrial radiography in a simplified and clear way'. Whilst the focus / intention is well placed, unfortunately the errors noted are so fundamental to radiation protection that this AI image should have been critically reviewed before being posted on social media. Many similar examples have been noted- particularly in 'informational posts' placed on LinkedIn. One role of the RPO in the image would be to point out the errors noted!
[Ionactive comment : we are not immune to making mistakes. Some time ago we asked AI for the TVT (10th value thickness) of lead for F-18, as an experiment. It came back with 22mm lead - this is wrong! When AI was questioned, it was stated that the data had come from the Ionactive website! We checked this out and realised there was a typo - we had written 22 mm and not 17 mm. We are proud to note that AI (all the engines) often quote Ionactive as an authority on radiation protection - that is welcome! But it clearly shows that AI was prepared to present 22 mm as fact, when it was actually 17 mm. We obviously quickly edited the page and now the correct data is served. But this shows us that whilst AI is amazing at manipulating data and coding etc, it still relies on the body of information on the internet, so it is in all our interests to ensure that AI uses the correct data!]
Let's now look at the specifics and some numbers.
Use of leaded aprons during Industrial Radiography?
Typical properties of leaded aprons
Leaded aprons and other garments (e.g. thyroid collars) are used in diagnostic radiology (medical sector), particularly during real time fluoroscopic procedures where the x-ray beam is continuous over a particular period, as compared to a radiographic 'shots' over msec exposures. They are designed to attenuate secondary scattered radiation, not a primary x-ray beam.
There is a move towards non leaded garments (such as those which use barium / bismuth etc), but in all cases a lead equivalence will be given. Typical lead equivalence will be from 0.25 - 0.5 mm. For the purposes of this article we will assume 0.5 mm lead equivalence as a maximum (regardless of the actual attenuating material used).
Typical attenuations available for intended uses
This type of PPE is used with x-ray generators operating from 60 - 120 kV, with perhaps some use up to 150 kV (with diminishing protection). At the lower energy range (say 60-90 kV) you might be looking at over 90 % attenuation from scattered x-rays.
Notwithstanding the use of this PPE for scattered radiation, it is illustrative to try the Ionactive Diagnostic X-ray Shielding / Transmission Calculator with some lead thickness and kV and see the theoretical attenuation provided.
Here is some attenuation data for 0.25 mm, 0.35mm and 0.5mm lead equivalence.
kV | 0.25 mm | 0.35 mm | 0.5 mm |
|---|---|---|---|
60 | 98.55 | 99.49 | 99.87 |
70 | 96.72 | 98.51 | 99.47 |
80 | 94.25 | 96.93 | 98.63 |
90 | 91.59 | 95.07 | 97.48 |
100 | 88.98 | 93.25 | 96.34 |
110 | 86.50 | 91.67 | 95.46 |
120 | 84.13 | 90.25 | 94.77 |
As you can see from the above table, useful attenuation is provided with all lead equivalences, for all the kV explored. Clearly 0.5 mm lead equivalence is best with over 95% attenuation for 60-110 kV (recall that this is looking at primary x-rays from the Ionactive calculator, so scattered x-ray performance will be even better).
To see how this works practically, assume the unprotected trunk of the body is exposed to a dose rate of 1000 μSv/h from a 100 kV x-ray source. If a 0.5 mm lead equivalent apron is being worn, the expected post-shielding (PPE) exposure would be 36.6 μSv/h (i.e. based on 100%-96.34% = 3.66% transmission). Note in this example that:
- Scattered radiation will be of lower average energy, so the transmission will be less than shown by this calculation.
- For many applications (e.g. conventional radiology), there is no dose rate as such, rather there is a short term exposure (mAs) which will yield an accumulated dose per exposure for a given range of parameters. Total pre or post PPE exposures can then be evaluated by looking at workload and occupancy etc.
Likely radioactive sources used in industrial radiography
(Keep an eye on AI!)
Now we have set the scene, we can return to the central theme explored by this article - use of leaded aprons during industrial radiography. We will first look at two likely radioactive sources for this purpose : Ir-192 and Se-75. We will then look at some scenarios if a lead apron was used and see what advantages it yields. We could analyse 160 - 300 kV x-ray systems in the same way, but using radioisotopes is simpler for this article as we are then dealing with fixed energies. In addition, we can use data directly from the Ionactive resource: Radioactivity to Dose Rate Calculator to provide specific dose rates at the point of interest. This calculator can also handle shielding so we can illustrate the effect of using leaded aprons on post PPE exposures.
Examples using Se-75 and Ir-192 (20 Ci)
The use of 20 Ci (in a UK context) is deliberate, this is still common practice (even if the official records are in GBq). So the activity we are working with is 740 GBq for the examples which follow.
[Ionactive note: The values given below from the above referenced Ionactive dose rate calculator are given in terms of effective dose equivalent rate. If you find these values vary slightly from other popular online resources, be sure to check the dosimetric quantity being calculated (often this is not quoted). If values reported are lower than specified below, this is likely because the resource is outputting / quoting absorbed dose in air (even if this is not stated). The Ionactive online calculators output dose rates as an absorbed dose rate, and an effective dose equivalent dose rate. Our core calculator engine is also audited against the latest version of MicroShield by Grove Software. ]
Se-75 (Selenium-75) is medium energy beta (strictly electrons) / gamma emitter with a half-life of approximately 120 days. The most important photon emission lines of interest are 317 keV (83%), 265 keV (59%), 401 keV (12%). An unshielded dose rate from 740 GBq (20 Ci) of Se-75 at 2 m would be : 10.33 mSv/h.
Ir-192 (Iridium-192) is medium energy beta / gamma emitter with a half-life of approximately 74 days. The most important photon emission lines of interest are 136 keV (59%), 468 keV (48%), 308 keV (30%) and 296 keV (29%). An unshielded dose rate from 740 GBq (20 Ci) of Ir-192 at 2 m would be : 21.68 mSv/h.
Let's look at some attenuation data for each of these sources - based on 0.25, 0.35 and 0.50 mm lead aprons.
Radionuclide | 0.25 mm | 0.35 mm | 0.5 mm |
|---|---|---|---|
Se-75 | 12.53 | 17.10 | 23.49 |
Ir-192 | 5.27 | 7.27 | 10.26 |
It is obvious that the attenuation is considerably less than for the diagnostic x-ray data given above. Attenuation for Se-75 is better than for Ir-192 as expected given the photon emission energies.
Assume that a pre-shielded dose rate is 1000 μSv/h and that a 0.5 mm lead equivalent apron is being worn. The expected dose rate reduction would be:
- Ir-192: 897.4 μSv/h.
- Se-75: 765.1 μSv/h.
It is clear that dose rate reduction is significantly less than for the diagnostic x-ray examples given earlier.
Noting the dose rates above for 20 Ci (740 GBq) at 2 m, the attenuated dose rates would be as follows (for 0.5mm lead equivalence)
- Ir-192: 19.46 mSv/h [down from 21.68 mSv/h]
- Se-75: 7.90 mSv/h [down from 10.33 mSv/h]
There is some dose saving but is it not significant and is provided by a PPE garment which is adding significant weight to the wearer for negligible net benefit.
From a UK perspective, especially in terms of open site industrial radiography, all personnel should at the very least be behind a physical barrier where instantaneous dose rates (IRD) are < 7.5 μSv/h. Therefore the use of lead aprons is negated by procedural and physical barriers in this case. Even better, enclosure radiography could be performed where dose rates on the safe shielded side would usually be approaching background levels.
What about source recovery?
Suppose an Ir-192 source has failed to retract into a safe storage position. A radiography technician needs to be within 1m of the 20 Ci (740 GBq) source to manipulate the source into a safe position using CV reachers. What is the exposure potential with or without the 0.5mm lead equivalent apron (noting the apron will add at least an extra 7kg to body weight).
An unshielded dose rate at 1 m from the Ir-192 source would be: 86.73 mSv/h. Suppose 1 minute of working time was required - this could yield an exposure of 1.46 mSv. Wearing the leaded apron would reduce this exposure to 1.31 mSv, hardly a dramatic dose saving where a few seconds of exposure over or under the 1 minute will have a significant effect on dose uptake. In this case the radiation protection principles of time (minimise) and distance (maximise) are far more important. In fact, wearing this leaded PPE could provide a false sense of additional safety (psychological shielding) , leading to longer exposure times and increased dose uptake.
Also note that a near 10% reduction in radiation exposure due to wearing the leaded apron only needs a 10% increase in exposure (i.e. 6 seconds for our above example), before any shielding advantage is negated.
It is true that if every other area of radiation protection was optimised in the above scenario, then additionally wearing the leaded apron could numerically reduce exposures further (marginally so). But wearing leaded PPE as a form of primary (and / or routine) protection in this scenario is poor practice and is not ALARP (as low as reasonably practicable).
[Ionactive note: as stated earlier, all figures are being derived from the Ionactive Radioactivity to Dose Rate Calculator and are in effective dose equivalent.]
40th Anniversary of the Chernobyl Disaster
We cannot leave this discussion without considering the 40th anniversary of the Chernobyl nuclear disaster. In particular we are looking at the 'Liquidators' who were tasked with many of the early clean up operations.
Some of these involved shovelling graphite and nuclear fuel pieces back down into the burning core - a significant hazard by any standard. It is reported (Chernobylgallery.com) that the liquidators literally stripped lead from the working environment to fashion lead plates front and back of between 2-4mm thick. No mean feat in that the lead would probably add 30+ kg of additional mass to the body which would need to be moved around quickly. It is further reported via the referenced link (and other sources) that helicopter pilots tasked with dropping lead / sand / boron mixtures directly into the core of the damaged reactor, had fashioned lead plates into their seats.
If we just consider external gamma radiation hazards (Sr-90 was a significant beta radiation hazard which will not be explored further in this article), then the dominant radionuclides were likely:
- Cs-137 (Cesium-137) - with gamma emission of 662 keV.
- Cs-134 (Cesium-134) - with multiple gammas averaging around 700-800 keV.
- Zr-95 (Zirconium-95) / Nb-95 (Niobium-95) - with gamma energies of around 720-770 keV.
Setting an average energy of say 700 keV, yields an HVT (1/2 value thickness) for lead of about 6.5 mm. We can then estimate the % transmission or attenuation which will be:
- 2 mm lead: 81% transmission (19% attenuation).
- 4 mm lead: 65% transmission (25 % attenuation).
Note: it would be impracticable (too heavy) to wear 4mm lead plates front and back.
According to the above reference, and also this wiki link: Chernobyl disaster, the intended stay time for the Liquidators was 60-90 seconds (per session / operation). Dose rates varied considerably with some no go areas of over 100 Sv/h. Looking at the data a working area external gamma dose rate of perhaps 1 Sv/h was likely. Let's look at potential accumulated exposure over 90 seconds with no lead, 2 mm lead and 4 mm lead (for the 4 mm lead we will assume this was worn only on the front and they walked backwards away from the hot zone).
- No lead: 90 seconds - 25 mSv.
- 2 mm lead: 90 seconds - 20.24 mSv.
- 4mm lead: 90 seconds - 16.25 mSv.
From the references it appears that average (external) whole body dose per individual was more like 250 mSv - so would imply either multiple sessions, longer exposures or higher dose rates (or some combination).
ALARP does play significantly here. 30kg+ of lead is going to require greater physical exertion. Heavier breathing with poorly fitted or inadequate respiratory protection will increase the likely internal radiation exposure. Just slowing down is likely to increase exposure times which will rapidly void any advantage of using the lead PPE.
Perhaps the advantage here is psychological - feeling that they are protected from the radiation hazard. Overall this is an extreme case - highlighted due to the 40th anniversary and a useful comparison with the significantly less extreme radiological conditions present during industrial radiography!
Ionactive - Radiation Protection Adviser
This article is important radiation protection resource. However, it does not influence the Ionactive general Radiation Protection Adviser (RPA) service. We look after our ionising radiation user clients, and whilst we will always question IRR17 compliance where necessary , we will always work with the client and UK regulators to achieve desired compliance at all times. However, it is absolutely right to challenge and discuss current radiation protection regulation, and the use of radiation protection PPE in industrial radiography and other related potentially high dose rate work with ionising radiation.
Mark Ramsay
Radiation Protection Adviser (RPA)
Ionactive Consulting Limited (May 2026)