Background Factors Affecting the Radiation Exposure of the Lens of the Eye among Nurses in Interventional Radiology: A Quantitative Observational Study

Round 1

Reviewer 1 Report

Pag.1line 35. Comment: Interventional radiology has been dealing with parts other then cardiology and the cerebrovascular sector for many years. It is better to clarify this.

Pag. 2, line 52; It is true that RELID states: “20–40% of technicians or nurses had posterior subcapsular opacities compatible with injuries derived from exposure to ionizing radiation”.If you go to: https://www.iaea.org/resources/rpop/resources/relid-study, you notice that the study refers to nations with non-advanced healthcare systems. Usually these workers absorb low doses, such as not to cause pathologies, see also ref 15. Also in this case, it is better to clarify it.

Pag. 4 Room i; I think it is better to put ” i” in subscript.

Pag.15 Conclusions: How does Japanese law classify these workers? In Europe they would be exposed to category B and are subjected to dosimetric and health surveillance. What is it like in Japan? Is it appropriate to provide them with protective glasses and/or dose monitoring of the lens? In my opinion, no, but it is important to establish a conclusion in this sense.

Author Response

Response to the Reviewer #1

1. 1line 35. Comment: Interventional radiology has been dealing with parts other then cardiology and the cerebrovascular sector for many years. It is better to clarify this.

According to Reviewer #1's comments, we rewrote the phrases in the Introduction section: Interventional Radiology (IR), a diagnostic and treatment technique using fluoroscopy, was proposed by Margulis [1], and Wallace reported its application to the diagnosis and treatment of patients with neoplastic diseases [2]. Recent advances in X-ray fluoroscopy unit performance and the development of new tools and devices mean that IR is now expanding to many body parts, such as cardiovascular and cerebrovascular fields.

2. 2, line 52; It is true that RELID states: “20–40% of technicians or nurses had posterior subcapsular opacities compatible with injuries derived from exposure to ionizing radiation”. If you go to: https://www.iaea.org/resources/rpop/resources/relid-study, you notice that the study refers to nations with non-advanced healthcare systems. Usually these workers absorb low doses, such as not to cause pathologies, see also ref 15. Also in this case, it is better to clarify it.

Thank you very much. In response to your suggestion, we have made the following corrections in the relevant sections to help readers understand more accurately: In six countries where differences in healthcare systems may lead to differences in eye exposure levels, the Retrospective Evaluation of Lens Injuries and Dose (RELID) study was conducted under the auspices of the IAEA in 2008 and found that approximately 40–50% of interventionists and 20–40% of technicians or nurses had posterior subcapsular opacities compatible with injuries derived from exposure to ionizing radiation [23–27].

3. 4 Room i; I think it is better to put “i” in subscript.

Amended. Other similar subscripts have also been corrected.

4. 15 Conclusions: How does Japanese law classify these workers? In Europe they would be exposed to category B and are subjected to dosimetric and health surveillance. What is it like in Japan? Is it appropriate to provide them with protective glasses and/or dose monitoring of the lens? In my opinion, no, but it is important to establish a conclusion in this sense.

Under Japanese law, the Regulations for Prevention of Ionizing Radiation Hazards, dosimetry and health surveillance of radiation workers are not grouped according to the exposure dose level. However, both are mandatory for those permanently engaged in radiation work. Dosimetry is also required for those who temporarily enter a radiation-controlled area. If the exposure dose is relatively high, two dosimeters are required, the main one inside the lead apron and the additional one outside the lead apron. However, if the exposure dose is sufficiently low, as is the case for nurses, one main dosimeter on the outside of the lead apron is sufficient. In Japan, it is permitted by law to wear a lens dosimeter near the eye inside protective glasses, but this may only be necessary for physicians with exceptionally high doses. It should be recognized that personal protective equipment such as protective glasses and lead aprons are the last choice for dose reduction. We agree with Reviewer #1's comments that protective glasses are not necessary if the appropriate use of RSS and CSSs can adequately control radiation exposure. We added some phrases to the Conclusion section as follows: This study also showed that the lens equivalent dose for IR nurses was well below the dose limit, so wearing lead protective glasses is not mandatory. However, monitoring the lens dose outside the lead apron is necessary to ensure the dose is zero or very low.

Reviewer 2 Report

This is a well written article, using good English. It confirms that in practical reality, nurses should keep at safe distances whenever possible from fluoroscopy sources to reduce their radiation exposures. The study was based on ocular lens doses, but the doses received will also have application to cancer induction e.g. to skin and superficial tissues of the face.

The methodology is meticulous and although some of the content will be of interest to medical physicists. Such detailed physical content should be given as appendices or supplementary information rather than in the main text. The graphical displays are impressive and one can see the effect of distance very clearly; some again may be placed in supplementary information files. The statistical analysis is sound.

For the nursing readership, the authors should clearly state what the effects of excess radiation to the lens are and perhaps provide a photograph example of a radiation-induced cataract, with a reference to perhaps some commonly available textbook where further information is available. The authors should also state that the commonest cause of cataract is old age and ultra-violet light exposure, although steroid medication and diabetes can also cause this to occur.

Also,

1.      a table of the many (quite complex and difficult) symbols used should be inserted with good definitions for each symbol.

2.      In the graphics, the axes labelling should contain words as well as the short-form symbols, otherwise they will tend to confuse the readership. I accept that this is commonly done in physics journals, but this is a nursing/medical journal.

The small risk of additional carcinogenesis in the facial region might also be mentioned.

Author Response

Response to the Reviewer #2

1. This is a well written article, using good English. It confirms that in practical reality, nurses should keep at safe distances whenever possible from fluoroscopy sources to reduce their radiation exposures. The study was based on ocular lens doses, but the doses received will also have application to cancer induction e.g. to skin and superficial tissues of the face. The methodology is meticulous and although some of the content will be of interest to medical physicists. Such detailed physical content should be given as appendices or supplementary information rather than in the main text. The graphical displays are impressive, and one can see the effect of distance very clearly; some again may be placed in supplementary information files. The statistical analysis is sound.

Thanks for the comments. This paper examined the factors affecting IR nurse exposure regarding time, shielding, and distance. Each figure or table presented here is constructed with the minimum amount of information necessary to logically describe the contribution of factors related to these three concepts, and all of them cannot be excluded. Thanks for understanding.

2. For the nursing readership, the authors should clearly state what the effects of excess radiation to the lens are and perhaps provide a photograph example of a radiation-induced cataract, with a reference to perhaps some commonly available textbook where further information is available. The authors should also state that the commonest cause of cataract is old age and ultra-violet light exposure, although steroid medication and diabetes can also cause this to occur.

We added these phrases before the RELID study: When the eye's lens is exposed to radiation, opacity appears, and this lens opacity progresses to the point of visual impairment called a cataract [9,10]. There are three predominant forms of cataract depending on the location of the cataract: cortical cataract, nuclear cataract, and posterior subcapsular cataract (PSC) [11]. The PSC is considered a characteristic finding of radiation cataracts [12-14]. Cataracts may also occur with age [15], UV exposure [16-19], corticosteroid medication [20,21], and diabetes mellitus [22].

Photographs of actual cases of radiation cataracts can be found in the following references cited in the text above.

1) Merriam, G. R., Jr., & Worgul, B. V. (1983). Experimental radiation cataract--its clinical relevance. Bull N Y Acad Med, 59(4), 372-392.

2) Vañó, E., González, L., Beneytez, F., & Moreno, F. (1998). Lens injuries induced by occupational exposure in non-optimized interventional radiology laboratories. Br J Radiol, 71(847), 728-733. doi: 10.1259/bjr.71.847.9771383

3) International Commission on Radiological Protection. ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs—threshold doses for tissue reactions in a radiation protection context; ICRP publication 118: Ann. ICRP 2012, 41, 1–322. doi: 10.1016/j.icrp.2012.02.001

3. Also, a table of the many (quite complex and difficult) symbols used should be inserted with good definitions for each symbol. 

Thank you for your comment, we have added the following brief description of H_{T Lens}, P_KA and FT to the footnotes.

･H_{T Lens}: Lens-equivalent dose. The dose calculated for the lens of the eye, based on the physical dose dissipated to a lens, is adjusted to account for the effectiveness of the type of radiation.

･P_KA: Air kerma-area product. The integral of air kerma across the entire X-ray beam emitted from an X-ray tube.

･FT: Fluoroscopic time. The time when the x-ray beam is irradiated from the fluoroscopy system.

4. In the graphics, the axes labelling should contain words as well as the short-form symbols, otherwise they will tend to confuse the readership. I accept that this is commonly done in physics journals, but this is a nursing/medical journal.

Thanks for the valuable advice. We put the axes labeling on each part in Figure 2.

5. The small risk of additional carcinogenesis in the facial region might also be mentioned.

According to the reviewer's suggestion, we added some phrases to the discussion section: To date, there have been no reported cases of skin cancer in medical staff exposed to such low doses of scattered X-rays. However, since carcinogenesis is considered a stochastic effect with no threshold dose, it would be difficult to say there is no risk.