Imaging Applications Test 1 Flashcards
True or False: 1. Stochastic effects are usually associated with high dose radiation levels of exposure resulting in cell mutation of death and/or degenerative changes in the tissues exposed
False.
What are the two filters in a TLD badge?
- Aluminium and Plastic
What is the equivalent dose that the hands and feet are allowed to receive in one year for radiation personnel?
500mSv
What are some types of radiation personnel monitoring badges/devices that may be used to monitor workers radiation exposure?
- Thermoluminecent dosimeter
- Optically Stimulated Luminescence
- Pocket Dosimeter
- Direct Ion Stimulated dose meter
ESR’s Personnel Dosimetry Services term Hp(10) can not be used to measure:
An equivalent dose of 500mSv - thats HP(07)
HP(10) measures extremities (500mSv), lens of the eye (150mSv), and Whole body dose (20mSv avraged over 5 years)
The radiation protection regulations 1982 state that in most cases the longest a badge can be issued for it?
3 months
The filters on the TLD badge assist in determining the type of radiation that caused the exposure. What does a recording under the aluminium filter indicate?
Indicates shorter/higher energy x-rays. It will also tell you the radiation dose received to the whole body barring the skin.
What are some disadvantages for the use of TLD badges for personnel monitoring?
- Non-immediate reading/results
- can only be used once
- Specialist equipment needed to get a reading
- Can only read x-ray’s coming from the front of the badge
What are some advantages for the TLD badges for personnel monitoring?
- Small and Light Weight
- Cheap
- Robust
What is Stochastic Effects
A random effect caused by low dose radiation exposure
The effects of ionising radiation on humans and other living tissue is the result of interactions at the ________ level
Atomic
How would you express what is the lethal dose that would kill fifty percent of the exposed population in thirty days?
LD50/30
What does LD50/30 mean?
The lethal dose that would kill fifty percent of the exposed population in thirty days
What is a deterministic effect of radiation?
Related directly to a high dose of radiation
What is an example of stochastic effect
Radiation induced leukaemia
What is the principle effect behind the ALARA principle is
Stochastic
What is a Genetic effect?
Effects appear in the offspring of an individual who received the agent and the agent was encountered preconception
What is a Somatic effect?
The effects appear in the exposed individual
What is a Teratogenic effect?
effects appear in the offspring of an individual who received the agent and the agent was encountered during the gestational period
Lithium Fluoride (LiF) chips used in TLD badges can be read by exposing them to:
Heat.
When its exposed to heat it EMITS light - The amount of light emitted is proportional to the amount of radiation that the disc absorbed
TLD personnel monitors use lithium fluoride (LiF) crystals. Why?
LiF has a z number close to that of tissue
A general MRT rostered to fluoroscopy for the day should generally wear?
one TLD badge at waist height, under the lead apron
Non-Radiation Personnel:
“An equivalent dose to the skin of ___ mSv over any 1cm2, regardless of the total area exposed, in any one year”
50mSv
Non-Radiation Personnel:
“An effective dose of ___ mSv in any one year”
1mSv
Non-Radiation Personnel:
“An equivalent dose of ____ mSv to the lens of either eye in any one year”
15mSv
As per radiation protect regulations 1982, it is compulsory to monitor staff if they should receive in any period of one year a dose equivalent to, or exceeding ______ of the reference dose
0.3mSv
What dose CSP5 state in regards to Radiation Personnel who declare themselves pregnant?
For women for declare themselves pregnant, a dose of 2mSv at the surface of the abdomen over the remainder of the pregnancy
What is the lead equivalence minimum thickness of a gown used to cover a pregnant patient?
0.50mm
CSP 5 states that “where the foetus has been irradiated in the course of an x-ray examination of the mother, and dose to the foetus may exceed 5mSv, a ______ shall estimate the dose involved and shall advise on the ensuring radiation risk”?
Qualified health physicist
CSP 5 states that “it should be assumed that a women is _______ if she has clearly missed her most recent expected menstruations”?
Pregnant
What are the conditions of people holding patient or IR?
- Must be over 18
- Members of the public are most preferred
- Non-radiation personnel are next preferred
- Radiation personnel can hold but are the least preferred.
According to CSP5, who cannot hold a patient or IR?
- The same person each time
- Pregnant Personnel
- Personnel under the age of 18
What is the most correct process to follow when performing a radiological exam on a heavily pregnant patient (37/40) to investigate if the patient hurt her right wrist after a fall?
Use an apron of .50mm lead equivalence to cover the patients abdomen
A pregnant patient is brought in to the emergency department with a compound fracture to her left femur after being involved in a car accident. She is to be sent to CT and then straight in to theatre to control the bleeding and operate on the fracture. Who would approve the CT?
Radiologist
According to target theory, cell death will only occur if the target molecule is inactivated. What is the target molecule?
DNA
During the pre-implantation stage of the developing embryo the most significant risk is?
Prenatal death
What are some examples of deterministic effects?
- Neurovascular Syndrome
- Cateracts
- Acute radiation sickness
The ionisation of DNA is a result of what type of interactioin?
Direct
The ionisation of water molecules can lead to the creation of?
Free Radicals
What is the most sensitive stage of a cell for radiation damage?
M-stage
The least sensitive stage of a cell for radiation damage is
S- stage
What are the relative radiation sensitivity of the following:
- Lymphocytes
- Nerve
- Reproductive
- Lymphocytes: High
- Reproductive: Medium
- Nerve: Low
What are some types of DNA mutations?
- Mainchain scission
- Cross-Linking
- Point Lesion
When is Radiation-induced damage in tissue the greatest?
Is greater in the presence of oxygen
The relacement of damaged cells in an organ with fibrotic scar tissue which comprisesthe function of the organ is an example of:
Repair
What are the five R’s principles of fractionation that is used in radiation therapy?
- Repair
- Redistribution
- Reoxygenation
- Repopulation
- Radiosensitivity
The exposure of high doses of radiation over brief intervals of time produces _____ effects?
Acute
The LD50/60 for humans is approximately?
3-5mSv
The LD50/60 for humans wuth sensitive medical care may be as high as?
6-8mSv
The average annual MRT occupational exposure is:
0.5mSv
What is the annual background radiation in NZ averages?
2mSv
Define Latent
Like an incubation period where initial symptoms subside
Define Manifest Illness
Abrupt onset of moderate to severe symptoms relevant to the underlying organ system damage
Define Prodromal
Initial symptoms that can begin minutes to hours after exposure
Define Recovery
Stage that may take weeks to months
CSP5 calls for signs to be displayed in the public area of an imaging department, including in the changing rooms, saying what?
To inform the MRT, nurse or doctor if you are pregnant
At what stage of embryonic development does radiation have an “all or nothing” effect?
Pre-implantation stage
What stage of embryonic development is there the highest risk from radiation exposure?
Pre-implantation
What is the lethal dose limit for the pre-implantation stage of pregnancy?
0.05-1 Gy
What is the lethal dose for the organogenesis stage of pregnancy?
1.5Gy
What is the lethal dose for the foetal stage of pregnancy?
2-3 Gy
What is the maximum latency time period that research indicates it may take for a solid radiation induced cancer to become apparent?
80 Years
In Sieverts, what is the threshold for radiation induced cancers?
Anything above 0 mSv
If a chest/abdomen/pelvis CT delivers 5.5mSv of ionising radiation, this is equivalent to how many months of background radiation?
33 months
If radiation exposure of the developing embryo occurs during the foetal stage, growth retardation is likely to only be temporary?
True/False
False
At 2.5mSv, an AP lumbar radiograph is equivalent to how many months of background radiation?
a. 15 months
Mental Retardation is a result of..
Deterministic Effect
During the pre-implantation stage of the developing embryo the most significant risk is?
a. Prenatal death
What is fractionation?
Technique of giving small doses regularly for radiotherapy
Which statement best described haemopoietic syndrome?
Radiation effects related to blood forming tissues, normally indicated by change in blood cell counts
Describe what a point lesion DNA mutation is?
A disruption of a single chemical bond which is not detectable but can cause malformation within the cell
The most radiation sensitive cells in the body are those that are:
Have a high division rate
What does the term LET- linear energy transfer mean?
Measure of the rate at which energy is transformed from ionising radiation to tissue
What cells is least sensitive to the effects of ionising radiation?
Nerves
What are are carcinogenic agents?
Radiation, Pesticides, Viruses
During pregnancy, the most sensitive time to radiation exposure of the foetus is?
Conception to 7 weeks
he main type of cancer observed in the radium clock/watch painters was?
Bone
Radiation expressed as 50/10^6/10mSv means?
50 deaths per million per 10 millisieverts
What is Radiation?
Emission or transmission of energy in the form of waves or particles through space or a material medium
Which type of cancer accounts for about half of all childhood cancers?
Leukemia
List four studies that our knowledge about the effects of radiation come from?
- Chernybol
- Fukushima
- Radium Girls
- Japan A bomb Survivours
Give two examples of practical steps that a pregnant MRT can take to minimise radiation dose to themselves and the foetus?
- Approach the boss early
- Avoid theater, fluro etc
- List three steps or special attentions that an MRT can take when performing an x-ray on a pregnant patient?
- Tight collimation
- High kVp technique
Reduce views by talking to the radiologists
At 75kVp, a lead apron of 0.5mm lead equivalence, provides ______ attenuation of the x-ray beam?
90%
The waiting area in a department for pregnant patients waiting to receive an ultrasound should not also be shared with patients awaiting for what other type of imaging?
Nuclear Medicine
The dosimetry reporting produced by ESR’s personnel Dosimetry Service is quoted in?
mSv
Optically stimulated luminescence uses ______ to obtain the measurement of radiation exposure
Laser
What is an example of a stochastic effect?
Radiation induced leukaemia- stocastic effect
Name some advantages and disadvantages of TLD Badges and OLD
Advantages:
- Lightweight
- Cheap
- Robust
- Can just be mailed to centres
- Reusable
Disadvantages:
- Long delays between incident and results
- Requires specialist equipment to read
- The evidence is destroyed when disk or chip is progressed
Name some advantages and disadvantages of pocket dosimetry
Advantages:
Results are quick but not instant
Disadvantages:
- Cost
- Fragile
- Results are not recorded as part of the reading process
Name some advantages and disadvantages of Direct Ion Storage Dosimeters
Advantages:
- Uses an ionisation chamber to produce instant results
- Electronic warining if dose exceeds limit
- USB version has memory and uploads automatically in connection to a computer
Disadvantages:
- Cost
- Instrument strong but not indestructible
- If older LCD model, manual recording of dose is required.
