Multiple Choice Questions

BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any reliance Supplemental material placed on this supplemental material which has been supplied by the author(s) Heart

Multiple choice questions

1. When the distance from the source of radiation is doubled, the amount of radiation received by the operator will be?

a. Tripled b. Doubled c. The same d. Reduced by ½ e. Reduced by 3/4

Increasing the distance between the operator and the radiation source, will reduce exposure by the square of the distance from the source. Doubling the distance between the operator and the radiation source will reduc radiation exposure by a factor of 4.

2. During X-ray diagnostics, a staff member wears personal protective clothing – which of the following offers the best protection? a. an apron with a thickness of 0.25 lead-equivalent without a thyroid collar b. an apron with a thickness of 0.25 lead-equivalent and a thyroid collar c. an apron with a thickness of 0.35 lead-equivalent without a thyroid collar d. an apron with a thickness of 0.35 lead-equivalent and a thyroid collar e. an apron with a thickness of 0.15 lead-equivalent and a thyroid collar

Lead aprons are the primary radiation protective garments used by staff during exposure to X rays. The radiation protection provided by a lead apron is approximately the same as 0.25- to 1-mm thick lead. Thicker aprons are usually more protective but heavier. An apron with 0.5-mm thickness can attenuate approximately 90% or more of the scatter radiation. Lead glasses with 0.5- or 0.75-mm thickness can reduce more than 95% of scatter radiation. Lead aprons should have at least 0.25-mm lead-equivalent thickness on the back and front. Wraparound type aprons are designed overlapping 0.25 + 0.25 mm lead-equivalent thickness in the front (0.5 mm total). There are several different designs available, including aprons with front coverage only, aprons that wrap around the body, and a vest and skirt combination. The two piece aprons reduce the burden on the spine, by

Roguin A, Nolan J. Heart 2020;0:1–7. doi: 10.1136/heartjnl-2019-316369 BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any reliance Supplemental material placed on this supplemental material which has been supplied by the author(s) Heart

distributing the weight concentrated on the shoulders and back to the shoulders and hips The design of aprons does not shield the thyroid so it is necessary to combine the apron system with a separate thyroid collar to ensure that this radiosensitive organ is protected. Aprons of appropriate size and proper fit should be provided to each operator. A poorly fitted apron with large armhole gaps can result in increased exposure of breast tissue. The shielding materials inside protective garments may suffer damage after long-term use, such as cracks or holes, which may not be visible. Therefore, it is necessary to regularly inspect aprons and other radiation protective garments frequently to determine the degree of damage

3. Which type of tissue is most sensitive to ionising radiation? a. tissue that receives the largest dose b. tissue with cells that divide quickly c. tissue that is located in the abdominal region d. tissue with cells that no longer divide e. tissue of the lower limbs

Bone marrow and gastrointestinal cells divide rapidly and are the most sensitive to DNA damage from radiation

4. Which of the following effects of ionising radiation occurs with a probability that is NOT proportional to the received radiation dose? a. skin erythema b. Stochastic effect c. Cataract induction d. Hair loss e. Irreversible skin damage

Stochastic effects occur by chance and are not related to dose. By contrast deterministic effects such as skin or eye injury are related to received dose and only occur above a certain threshold. Cancer induction and radiation induced hereditary effects are the two main examples of stochastic effects.

5. Which radiation source in the catheterisation laboratory setting contributes most to the annual effective dose of the operator? a. direct radiation b. scatter radiation c. neither direct radiation nor scatter radiation d. both direct radiation and scatter radiation e. There is no radiation in the catheterisation laboratory

The patient receives radiation from the primary beam while the operator is exposed to scatter radiation arising from the passage of the x ray beam through the patient

6. ALARA stands for:

a. As Low As Responsibly Acceptable b. Alarm Loss Activated Radiation Activated c. As Low As Reasonable Achievable d. As Low As Reasonably Attenuated e. You’ll Never Walk Alone

We must keep the dose As Low As Reasonable Achievable (ALARA) while at the same time keeping the benefit from high level diagnostic imaging and optimal management. The three main principals are [1] Time (Reducing the time of exposure can directly reduce radiation dose) [2] Distance (Increasing the distance between the operator and the radiation source, will reduce exposure by the square of the distance. [3]. Shielding (lead aprons and glasses, lead barriers, mobile lead).

7. What is the correct table height?

a. Yellow b. Black c. Blue d. Red e. Between black and blue

The radiation tube converts electrical input power and sends energy as X rays through the radiation beam. The amount of energy depends on the peak AC voltage (in Volts), the tube current (in mili Amperes) and exposure time (in seconds). The energy is higher closer to the source. Elevating the table to its maximal usable height will reduce radiation to the patient, by increasing the patients distance from the radiation tube. This will also reduce scatter radiation to the operators. Therefore the position of the table should be as high as possible, and comfortable for the operator to avoid orthopaedic problems

What type of device is used to monitor individuals in order to determine their radiation exposure?

a) Film badge b) Geiger counter c) Alarm rate meter d) Ionization chambers e) Hillel Yaffe cell count

The film badge dosimeter or film badge is a personal dosimeter used for monitoring cumulative radiation dose due to ionizing radiation. The badge consists of two parts: photographic film, and a holder. The film emulsion is black and white photographic film with varying grain size to affect its sensitivity to incident radiation such as gamma rays, X-rays and beta particles. In the measurement laboratory, the film is removed, developed, and examined to measure exposure. When the film is irradiated, an image of the protective case is projected on the film. Lower energy photons are attenuated preferentially by differing absorber materials. This property is used in film dosimetry to identify the energy of radiation to which the dosimeter was exposed. The film badge is still widely used, but is being replaced by more modern thermoluminescent dosimeters (TLDs), aluminium oxide based dosimeters, and the electronic personal dosimeter (EPD).

Roguin A, Nolan J. Heart 2020;0:1–7. doi: 10.1136/heartjnl-2019-316369