Test examination

RPO MT

Tag one of the four alternatives (a, b, c or d) for each of the multiple-choice questions. Only one answer is correct. For the open questions 41 and 42, the complete calculations must be attached.

The examination is based on the syllabus Radiation Protection Officer - medical applications, written by F. Pleiter, H.F. Boersma and A.A. Froma. You will find the correct answers here .

Complete the sentence correctly: The number of electrons in an electrically neutral atom is equal to the...
1. neutron number
2. atoomnummer
3. mass number
4. difference between mass number and atomic number
Complete the sentence correctly: Characteristic X-radiation arises...
1. if an electron returns from one shell to a lower-energy shell
2. if an electron is decelerated
3. if an electron is accelerated
4. during the process of Compton effect
Complete the sentence correctly: The probability of the photo-electric effect to occur...
1. hardly depends on the photon energy
2. hardly depends on the atomic number of the material
3. increases if the photon energy becomes higher
4. increases if the atomic number of the material becomes larger
During X-ray diagnostics, the X-ray technicians wear personal protective clothing. Which one offers usually the best protection?
1. lead apron with a thickness of 0.25 lead-equivalent and a thyroid collar
2. lead apron with a thickness of 0.25 lead-equivalent without a thyroid collar
3. lead apron with a thickness of 0.35 lead-equivalent and a thyroid collar
4. lead apron with a thickness of 0.35 lead-equivalent without a thyroid collar
To answer the next questions, you may use the transmission through plaster (see figuur A ).
The tube voltage of an X-ray device is 90 kV. How many mm plaster is needed to reduce the intensity of the X-ray beam by a factor of 50 ?
1. 100 mm
2. 120 mm
3. 150 mm
4. 190 mm
The tube voltage of an X-ray device is 70 kV. While taking an X-ray photo, the radiographer takes position behind a stone wall with a thickness of 10 cm, thus reducing his effective dose by a factor equal to the transmission of the wall. To answer the next question, you may use the transmission through stone (see figuur B ).
What is the transmission of the stone wall?
1. 0.000 01
2. 0.0001
3. 0.001
4. 0.01
Complete the sentence correctly: Protection against X-radiation usually relatively simple because...
1. the penetration depth of X-radiation into the body is very small
2. the radiation weighting factor wR for X-radiation is very small
3. the dose rate of an X-ray device is always very small
4. X-radiation usually can be shielded with a thin layer of lead
Complete the sentence correctly: If one decreases the voltage across the tube while not changing the other settings of the X-ray device, then...
1. the energy of the characteristic X-ray radiation decreases
2. the energy of the characteristic X-ray radiation remains the same
3. the energy of the characteristic X-ray radiation increases
4. the yield of the X-ray tube remains the same
The half-value thickness is the amount of material needed to reduce the dose rate by a factor of two.
Which property holds for the radiation that is generated by an X ray device?
1. the half-value thickness of the primary beam is larger than the half-value thickness of the scattered beam
2. the half-value thickness of the primary beam is smaller than the half-value thickness of the scattered beam
3. the half-value thickness increases when the exposure time increases
4. the half-value thickness decreases when the exposure time increases
Which combination of tube current and exposure time produces the largest output dose of an X-ray device, all other settings remaining the same?
1. 4 mA during 0.4 seconds
2. 5 mA during 0.3 seconds
3. 6 mA during 0.2 seconds
4. 7 mA during 0.1 seconds
In an organ with a mass of 100 grams, an energy of 2 joules is deposited by X-rays.
How high is the absorbed dose in that organ?
1. 0.02 Gy
2. 0.05 Gy
3. 20 Gy
4. 50 Gy
Complete the sentence correctly: The tissue weighting factor w_T is used for the conversion from...
1. only equivalent dose to effective dose
2. only absorbed dose to equivalent dose
3. neither equivalent dose to effective dose nor absorbed dose to equivalent dose
4. both equivalent dose to effective dose and absorbed dose to equivalent dose
During breast cancer screening among women, one of the two breasts receives an equivalent dose of 0.7 mSv. The tissue weighting factor for breast tissue is w_breast = 0.12.
What is the contribution of this exposure to the effective dose of the woman?
1. 0.042 mSv
2. 0.084 mSv
3. 0.7 mSv
4. 5.8 mSv
Almost half of the radiation dose due to natural sources in the Netherlands is caused by a single type of source.
Which type of radiation source is this?
1. soil
2. cosmic radiation
3. radon
4. food
What does the precise working of an ionization detector depend on?
1. the dimensions of the detector
2. the pressure of the counting gas
3. the composition of the counting gas
4. the voltage between anode en cathode
The grey shade describes the average brightness of a photo: an underexposed photo is too light and an overexposed photo is too dark.

The difference in grey shades of light and dark parts of an X-ray image is called contrast. If the contrast is extremely large, only the shades white and black show up. If the contrast is extremely small, the image shows only a single shade of grey.

Only one setting of the X-ray device is changed. The other settings remain the same.
In which way can one reduce the contrast of an X-ray photo?
1. by increasing the voltage across the X-ray tube
2. by decreasing the voltage across the X-ray tube
3. by increasing the current through the X-ray tube
4. by decreasing the current through the X-ray tube
To make a specific X-ray image, the extra filter is removed, so that only the intrinsic filter remains. Tube voltage and mAs value remain unchanged.
What is the consequence of this for an X ray image?
1. the average grey shade decreases
2. the skin dose decreases
3. the contrast increases
4. the contrast decreases
A distinction is made between "aligned" and "non-aligned" Bucky anti-scatter grids.
Which of the following statements is correct?
1. an aligned grid is at a fixed distance from the focus
2. an aligned grid is mounted close to the X-ray device
3. a non-aligned grid is at a fixed distance from the focus
4. a non-aligned grid is mounted close to the X-ray device
In which type of tissue are cells most sensitive to ionizing radiation?
1. tissue that receives the largest dose
2. tissue that is located in the abdominal region
3. tissue with cells that no longer divide
4. tissue with cells that divide quickly
Which effect of ionizing radiation occurs with a probability that is not proportional to the received radiation dose?
1. a genetic effect
2. a stochastic effect
3. a tissue reaction
4. leukemia
Which disease can be regarded as a stochastic effect due to ionizing radiation?
1. leukemia
2. permanent sterility
3. temporary sterility
4. reduction in the number of white blood corpuscles
An unborn child receives an absorbed dose of 0.5 Gy during the first ten days after the conception.
What is the possible consequence of this irradiation for the child?
1. a tumor in later life
2. malformation of an organ
3. death shortly after birth
4. prenatal death
Which is the risk coefficient for fatal stochastic effects due to exposure to ionizing radiation?
1. about 0.01 per sievert
2. about 0.02 per sievert
3. about 0.05 per sievert
4. about 0.10 per sievert
What does the ALARA principle mean?
1. preference for any alternative method in which no ionizing radiation is applied
2. the received dose must be kept as low as reasonably achievable
3. the application must be justified, which means that the benefits outweigh the disadvantages
4. no dose limit shall be violated
According to the Decree on Basic Safety Standards Radiation Protection, which is the annual limit for the effective dose of an exposed category-A worker?
1. 100 μSv
2. 2 mSv
3. 20 mSv
4. 50 mSv
According to the Decree on Basic Safety Standards Radiation Protection, which is the annual limit for the equivalent dose on the lens of the eye of an exposed category-A worker?
1. 20 mSv
2. 50 mSv
3. 150 mSv
4. 500 mSv
According to the Decree on Basic Safety Standards Radiation Protection, an area in which ionizing radiation is applied must be designated as a supervised or controlled area. The criterion for this is the maximaum effective annual dose that may be received in this area.
What criterion must the effective annual dose in a supervised area meet?
1. higher than 1 mSv, but lower than 6 mSv
2. higher than 6 mSv, but lower than 10 mSv
3. higher than 10 mSv, but lower than 20 mSv
4. higher than 20 mSv
Does a risk inventory and evaluation (RI&E) always have to be carried out by the radiation protection officer?
1. yes
2. no, this may only be done by a registered radiation protection expert
3. no, this may only be done by radiation protection experts
4. no, this may in principle be done by everyone
Complete the sentence correctly: A cone-beam CT-scanner in the department of Oral and Maxillofacial Surgery...
1. may be used without any restrictions
2. is subject to a license
3. may be used without a radiation protection officer
4. must be registered with the ANVS
According to the Decree on Basic Safety Standards Radiation Protection, an X-ray device must be checked regularly for proper operation.
What is here meant with "regularly" ?
1. at least once a month
2. at least once in 6 months
3. at least once in 12 months
4. at least once in 24 months
According to the Regulation Basic Safety Standards Radiation Protection, a medical diagnostic X-ray device must be equipped with a diaphragm.
What does one want to limit with the diaphragm?
1. only the area exposed to the beam
2. only the distance between focus and skin
3. neither the area exposed to the beam nor the distance between focus and skin
4. both the area exposed to the beam and the distance between focus and skin
According to the RIVM, a patient receives an effective dose of 7.3 mSv on average as a result of a CT-scan of the pelvis. In order to comply with the specific justification for a CT-scan of the pelvis, the specialist asks his female patient about a possible pregnancy.
Complete the sentence correctly: In the context of individual justification, this question is...
1. understandable, but the question may not be asked under the Decree on Basic Safety Standards Radiation Protection
2. in violation of the General Regulation on Data Protection (AVG)
3. justified if the question is relevant in the opinion of the specialist
4. justified because it must always been asked under the Decree on Basic Safety Standards Radiation Protection
Consider the following two instructions to new employees:
Instruction I: Introducton into the house rules.
Instruction II: Introduction into the written protocols.
Which instruction belongs and which does not belong to the duties of the radiation protection officer?
1. instruction I and instruction II are both duties
2. neither instruction I nor instruction II are duties
3. instruction I is not to a duty, but instruction II is
4. instruction I is a duty, but instruction II is not
For a medical procedure, one often uses a diagnostic reference level (DRL).
Complete the sentence correctly: For medical procedures, ...
1. the dose for the patient should be lower than the DRL
2. the dose for the patient should be equal to the DRL
3. the dose for the patient should be higher than the DRL
4. the DRL is a means to apply ALARA
What is the largest contribution to the annual effective dose of a radiographer as a result of his or her work?
1. direct radiation
2. scatter radiation
3. neither direct radiation nor scatter radiation
4. both direct radiation and scatter radiation
Which measure leads to the largest dose reduction for the X-ray technician?
1. increase the distance to the radiation source by a factor of 2
2. increase the distance to the radiation source by a factor of 3
3. decrease the exposure time by a factor of 2
4. decrease the exposure time by a factor of 2 and also increase the distance to the radiation source by a factor of 2
A six month old child complains about sudden pain in the jaw. The mother brings the child to the department of Oral and Maxillofacial Surgery where it is decided to take an X-ray image of the jaw. Someone must keep the child on his or her lap.
Who is the first eligible?
1. the duty radiographer
2. the mother
3. a nurse practitioner
4. someone with the diploma Radiation Protection Officer
A mobile X-ray device is placed closer to the patient. The focus-skin distance was 180 cm, while it is 120 cm after the movement. The tube settings are not changed. The entrance dose was originally 1 mGy.
What is the entrance dose at the new distance?
1. 0.4 mGy
2. 0.7 mGy
3. 1.5 mGy
4. 2.3 mGy
Which combination of focus-skin distance and field size gives rise to the largest amount of scatter radiation?
1. focus-skin distance = 20 cm and field size = 15 cm²
2. focus-skin distance = 20 cm and field size = 30 cm²
3. focus-skin distance = 30 cm and field size = 15 cm²
4. focus-skin distance = 30 cm and field size = 30 cm²
An X-ray device is equipped with a 1.5 mm thick aluminum filter. To improve the contrast of the photo, the tube voltage is decreased from 80 kV to 70 kV. In order to obtain the same output dose from the tube, the mAs value has to be changed from the original 3 mA·s to a new value. To answer the next question, you may use the data in figuur C .

What is the correct new mAs value?

1.8 mA·s
2.6 mA·s
3.5 mA·s
4.6 mA·s

To answer questions 41 and 42, the full calculation must be given. Clearly indicate the calculation method and/or reasoning you use to arrive at the solution. Always state the quantities and units used.

Data for question 41
tube voltage	125 kV
filter	3 mm aluminum
tube current	50 mA
exposure time	5 seconds
yield of X-ray tube buis	see Figure C
distance focus - skin	70 cm

An X-ray image is taken in the Radiology department.

Calculate the entrance dose for the patient.
(maximaal 4 punten)

Data for question 42
number of photos per year	2000
average tube voltage	70 kV
average mAs value	1,5 mA·s per opname
filter	2 mm aluminum
yield of X-ray tube	see Figure C
distance focus - road	3 meters
thickness double glass	11 mm
transmission of glass	see Figure D
the contribution of scatter radiation can be neglected

There is an intra-oral X-ray device in the Oral Surgery department. For 50% of the photos, the X-ray beam is directed perpendicular to the double-glass window in the outer wall adjacent to the public road.

Check by means of calculation whether or not the shielding effect of the double glass in the window is sufficient to comply with the dose limit for the environment.
(maximal 6 points)

Last modified:12 December 2025 1.19 p.m.

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Test examination

To answer questions 41 and 42, the full calculation must be given. Clearly indicate the calculation method and/or reasoning you use to arrive at the solution. Always state the quantities and units used.

Data for question 41

Data for question 42