X-Ray Safety for Veterinarians: Daily Limits and Protection

Entering the X-ray room with animals?

Hello, Doctor.
Due to my work, I often accompany animals into the X-ray room for imaging, and sometimes I take up to 8 images in a day.
How many images can I safely take in one day? The X-ray settings include kV (commonly set between 50-150), mA (50-200), and exposure time (0.04-0.08 seconds), which vary depending on the target organ.
I couldn't find any information online about how to convert this to millisieverts, and I am unsure of the model of the X-ray machine.
Additionally, we only have lead aprons and thyroid collars for protection; if we do not use protection for our hands and head (especially the eyes), could this pose a risk? Thank you very much for taking the time to respond.

Shòuyīyuàn dǎzáigōng, 30~39 year old female. Ask Date: 2020/01/30

Dr. Wang Yifen reply Radiology

Hello, in Taiwan, operations involving ionizing radiation must comply with the "Ionizing Radiation Protection Act," which aims to reasonably minimize radiation exposure to protect health and safety.
The competent authority is the Atomic Energy Council of the Executive Yuan.
Regarding your question about how many X-rays can be taken in a day, safety regulations for X-ray imaging are not based on the number of X-ray films taken but rather on the radiation dose exposure.
According to Article 7 of the Ionizing Radiation Protection Safety Standards, the dose limits for occupational exposure of radiation workers are as follows:
1.
The effective dose over any continuous five-year period must not exceed 100 millisieverts, and the effective dose in any single year must not exceed 50 millisieverts.
2.
The equivalent dose to the lens of the eye must not exceed 150 millisieverts in any single year.
3.
The equivalent dose to the skin or extremities must not exceed 500 millisieverts in any single year.
To monitor the radiation dose exposure of workers, Article 15 of the Ionizing Radiation Protection Act states that employers must implement individual dose monitoring for radiation workers.
Radiation workers in hospitals use "dose badges" for dose monitoring.
You may consult your supervisor on how your organization implements dose monitoring for radiation workers.

The millisievert is the unit for "effective dose," which is calculated based on the absorbed dose of X-rays entering the skin, adjusted for tissue weighting factors (indicating the sensitivity of different tissues to different types of radiation).
Converting to millisieverts does not particularly affect radiation workers; what is more important is that the dose monitoring results remain within safe limits.

Regarding the model of the X-ray machine, its setup must comply with the "Regulations on the Management of Radioactive Materials and Equipment that Generate Ionizing Radiation and Their Radiation Operations." If you are unsure about the model of the X-ray equipment used in your organization, you can inquire with the equipment manufacturer or the personnel responsible for managing the X-ray equipment in your organization.

As for radiation protection gear, the main items are lead collars and lead aprons.
The protective gear for the eyes consists of lead glasses.
The risk of radiation to the eyes is an increased probability of cataracts; however, the likelihood of the lens of the eye reaching the exposure limit of 150 millisieverts is extremely low, even in hospitals, so lead glasses are not typically provided.
If your workplace is classified as a high-risk area, it is advisable to assess the need for purchasing lead glasses based on your requirements.

For more information on ionizing radiation, you can refer to the website of the Atomic Energy Council: https://www.aec.gov.tw/webpage/radtown/default.php.
I hope this information is helpful to you, and I wish you safety and health.

Reply Date: 2020/01/30

More Info

When it comes to X-ray safety, especially for veterinarians who frequently work in radiology, understanding the limits of exposure and the protective measures available is crucial. The amount of X-ray exposure a person can safely receive is governed by regulations that aim to minimize radiation risks while allowing necessary medical imaging to be performed.

Daily Limits for X-ray Exposure
The safety standards for radiation exposure are not strictly defined by the number of X-ray images taken in a day but rather by the total radiation dose received. In many countries, including the United States, the recommended occupational exposure limit for radiation workers is set at 50 millisieverts (mSv) per year, with a more conservative limit of 20 mSv per year averaged over five years. For specific organs, such as the eyes, the limit is lower, at 15 mSv per year.
In practical terms, the radiation dose from a single X-ray can vary significantly depending on the type of X-ray and the area being imaged. For example, a standard chest X-ray typically delivers about 0.1 mSv, while a more complex procedure, such as a CT scan, can deliver doses ranging from 2 to 10 mSv or more. Therefore, if you are taking multiple X-rays in a day, it is essential to monitor the cumulative dose to ensure it remains within safe limits.

Factors Influencing Radiation Dose
The settings you mentioned (kV, mV, and exposure time) directly affect the radiation dose. Higher kilovolt (kV) settings generally increase the penetration of the X-ray beam, which can lead to higher doses. Similarly, the milliampere-seconds (mAs) setting, which combines the current and time of exposure, also influences the total dose. Therefore, adjusting these parameters according to the specific imaging requirements can help manage the radiation dose effectively.

Protective Measures
Regarding protective gear, the use of lead aprons and thyroid collars is standard practice in radiology to protect vital organs from unnecessary radiation exposure. However, the hands and eyes are also at risk, especially in veterinary settings where the operator may be close to the X-ray source.
1. Hand Protection: If you are frequently holding animals during X-ray procedures, consider using lead gloves or other protective gear designed for hand safety. The hands can receive significant exposure if they are near the primary beam during imaging.

2. Eye Protection: While lead glasses are not commonly used in veterinary practices, they can be beneficial in high-exposure environments. The risk of cataracts increases with cumulative radiation exposure to the eyes, so if you are in a situation where you are frequently exposed to scatter radiation, it may be wise to invest in protective eyewear.

Monitoring and Safety Practices
It is advisable to implement a radiation safety program in your workplace, which includes regular monitoring of radiation exposure using dosimeters. These devices can track your cumulative exposure over time and help ensure that you remain within safe limits.

In summary, while there is no strict limit on the number of X-rays you can take in a day, it is essential to monitor the total radiation dose and implement protective measures to safeguard your health. Regular discussions with your radiation safety officer or a medical physicist can provide further insights tailored to your specific work environment and practices. Always prioritize safety and adhere to established guidelines to minimize risks associated with radiation exposure.

Similar Q&A

Facing the Fear of Blindness: A Young Professional's Eye Health Journey

Hello, Doctor. I am highly myopic with astigmatism and work in the technology industry, where I spend long hours using a computer. I have been working for less than a year. In April, I was suspected of having glaucoma, and in June, I underwent visual field tests, fundus photograp...

Dr. He Jianxian reply Ophthalmology
Hello: I think you are worrying too much. I suggest you come to our outpatient clinic for an examination; the explanation will be clearer. Wishing you good health.

Understanding Rigid Gas Permeable Contact Lenses for High Myopia

Hello Doctor: I have a myopia of 800 degrees. A few days ago, I went to an optical shop to get glasses, and they told me that my eyes are very demanding on vision and will continue to deteriorate. Therefore, they recommended that I wear rigid gas permeable contact lenses, which a...

Dr. Zhang Yanrui reply Ophthalmology
Hello: If you are over the age of 25, your vision is unlikely to change significantly unless there are some special pathological conditions. The advantage of orthokeratology lenses is that you do not need to wear contact lenses during the day, but if you stop wearing them for a w...

Understanding Eye Safety: Risks of Laser Exposure and Symptoms

Hello, doctor. A few days ago, a worker came to my house to install an air conditioner. One of the workers suddenly took out a laser distance meter and used it without any warning, pointing it in the direction of people. During the process, the laser beam hit my eyes, and I was a...

Dr. He Jianxian reply Ophthalmology
Hello Ms. C: Laser injuries occur immediately and will happen at the moment of exposure, and there will be no issues such as headaches. Therefore, if you have any concerns, it is advisable to get checked out directly. Director He Jianxian, Ophthalmology, Nantou Hospital.

Managing Myopia: Concerns About Switching Glasses for Art

Hello, doctor. I have a pair of glasses that I've been wearing for three years. A few months ago, I got a new pair with a prescription that is about 100 degrees stronger in one eye. Since I am an artist and often work at close distances, the doctor who prescribed my glasses ...

Dr. Gao Pilin reply Ophthalmology
Hello, Mr. Cao: I recommend using lower prescription lenses for long periods of drawing, as this can help reduce fatigue and is less likely to lead to presbyopia. The ophthalmology department at Puzi Hospital in Taiwan is open Monday to Friday from 8:00 AM to 12:00 PM and Wednesd...