R . Y . Nasr et al .: Radioprotection 2024 , 59 ( 3 ), 220 – 224 221
Numerous epidemiological studies from Hiroshima , Nagasaki , and Chernobyl child survivors have shown that low-dose radiation exposure and induced cataracts are correlated , and that posterior subscapular cataracts are more common in those who have had x-ray exposure from diagnostic imaging modalities ( Fish , 2011 ).
These have all highlighted the need for better measurement and more accurate personal dosimeters specific for the eye lens . A 3 mm depth has been recommended by the ICRP for measuring the dosage to the eye lens , Hp ( 3 ), but generally personal dosimetry to monitor skin doses Hp ( 0.07 ), the personal dose equivalent at a depth of 0.07 mm , is also used for this purpose . A dosemeter specifically designed for measuring HP ( 3 ) has been created by the Optimizations of Radiation Protection for Medical Staff Project ( Bilski , 2011 ). These were used at Mount Vernon Hospital and compared to the regular Hp ( 0.7 ) ( Summers , 2012 ). They have also compared their exposure and workload from a survey conducted in 2002 to 2011 . Staff wore separate pairs of TLDs on their foreheads when distributing , releasing , injecting , and giving I-131 capsules to patients . They reported eye lens doses from 0.18 to 4.51 mSv but also anticipated that the average annual occupational exposure to the eyes of staff members will continue to increase to levels higher than 6 mSv ( Summers , 2012 ).
In a nationwide study conducted in the United States , a group of radiology technicians assessed radiation-induced cataracts . More than 42,000 technicians were included in this study , and an elevated risk of cataracts was discovered . Compared with technicians who did not perform any nuclear medicine procedures , higher risks were observed in those who performed both diagnostic and therapeutic nuclear medicine scans ( Bernier , 2018 ).
Our study aimed to determine the current occupational radiation doses to the eyes of nuclear medicine staff . We used personal dose-equivalent Hp3 values from the annual Optically Stimulated Luminescence ( OSL ) dose reports spanning 2014 to 2022 . We also aimed to identify the staff categories subjected to high estimated eye doses . Additionally , we experimentally evaluated the effectiveness of the current protective measures in safeguarding the eyes of nuclear medicine staff .
2 Methods
King Abdulaziz University Hospital ( KAUH ) in Jeddah , Saudi Arabia , utilizes optically stimulated luminescent ( OSL ) badges with aluminum oxide chips for long-term radiation tracking . The OSL is a technology which now finds medical dosimetry applications in radiation dose measurement . The type of OSL dosemeter used is the ’ nanodot ’ that consists of a small disk ( 4 mm in diameter and ∼ 0.3 mm thick ) covered , when closed , in a 10 10 2 mm light-tight plastic casing meant to prevent light exposure of the sensitive element . This format is suitable to measure point doses with high spatial resolution . The screened nanodots have individual sensitivity factors provided by the manufacturer with 2 % of uncertainty . To check the sensitivity factor , a sample of 20 nanodots with 1.76 mGy from an 81 kV p 3.37-mm Al of HVL X-ray beam were irradiated . The readings corrected by sensitivity were then compared . Readouts of OSLDs were performed with a MicroStar reader ( Landauer , Inc .) using a laser diode working in the continuous wave mode ( CW ). With the CW mode , stimulating laser beam and fluorescent emission coexist and OSL fluorescence has then to be discriminated using a set of filters coupled with a photomultiplier tube . The reading process is fast ( ∼ 1 s ) portion of the traps is released ( 0.1-1 %).
Each staff member was provided with an OSL badge to be worn at collar level outside the lead apron . The OSL badges were read every quarter , and the minimum detectable dose ( Md ) was set at 0.1 mSv . Readings of 0.1 mSv are recorded as Md .
A 5 yr retrospective analysis was performed all staff involved in nuclear medicine procedures representing 100 % of the staff members from different categories ( nuclear medicine technicians , non-nuclear medicine ( cardiac stress ) technicians , hot lab technicians , and doctors ).
The H-lens values ( computed equivalent dose for the eye lens , Hp3 ) were extracted from the OSL system for each staff member . The H-lens variable was checked for normality , which indicated a non-normally distributed variable ( Shapiro- Wilk test , p < 0.0001 ).
3 Results
The mean eye lens dose among nuclear medicine workers was reported to range from 4 to 24 quarters in occupational dose records during the study period . The lowest mean dose was 0.26 ± 0.11 while the highest reported was 1.43 ± 0.88 .
Significant differences were observed between individual staff members in terms of H-lens values ( Tab . 1 ). In general , the differences in H-lens values between different occupations were significant ( Kruskal-Wallis rank sum test , p < 0.0001 ; Tab . 2 ). Pairwise differences revealed that H-lens values were significantly higher among hot lab technicians than among non-nuclear medicine technologists ( p < 0.001 ) and nuclear medicine technologists ( p < 0.0001 ). Other pairwise comparisons did not reveal any significant differences between the groups . The highest annual dose was received in 2015 and was reported to be for the radiologists as shown in Table 3 , it ’ s under the department investigation level
4 Discussion
Exposure to ionizing radiation is a fundamental concern in nuclear medicine because of the risk it poses to the health and safety of medical staff . Monitoring and controlling this exposure within acceptable limits is paramount . These limits are defined by international regulatory bodies such as the ICRP ( ICRP , 2012 ).
This study aimed to investigate the annual average eye dose of ionizing radiation received by nuclear medicine staff and compare the findings with those of other studies in the field . The goal was to understand whether the established safety protocols were effective , and whether staff exposure remained within the recommended dose limits .
In our study , none of the participants surpassed the eye dose limit for ionizing radiation exposure . The annual average eye dose ranged from 0.2 mSv to 2.9 mSv , which is within the advised dose limit stipulated by the ICRP . This is in higher than