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Radiation Protection
| Question | Answer |
|---|---|
| What is sued to account for the differences is tissue sensitivity to ionizing radiation wieh determining effective dose E? | tissue weighting factors (Wt) |
| a tune if 1.5 min is required for a particular fluoro ecam, whose exposure is 275 mR/h. What is the approsimate radiation exposure for the radiloric staff present in the flouro room during the exam? | (275(m/R)/60(min))=(x(mR)/1.5(min)) 60x=412.5 thus x=6.87 mR dose in 1.5 min 68.7 mR |
| if the exposure rate to an indicidual standing 4.0 m from a source of fadiation is 10 mR/h, what will the dose recieved after 20 minutes at a diastance of 6 m from the source? | (I1/I2)=d2^2/d1^2 (10/x)=(36/16) 36x=160 x=4.44 |
| the interaction betweem ionizing radiation and the target molecule that is most likely to occur is the | indirect effect |
| what is the apporox entrance skin exposure for the acerage AP supine abd x-ray | 300 mrad |
| how will x-ray photon intensity be affected if the sid is doubled | its intensity decreases four times |
| what is the established annual occupational dose-equivalent limit for the lens of the eye | 150 mSv |
| whaich of the following is used to account for the differences in tissue characteristics when determinig effective does to biologic material | tissue weighing factors (Wt) |
| the exposure rate to a body 4 ft from a source of radiation is 16 R/h. What distance from the source would be neceddary to decrease the exposure to 6 R/hr | (I1/I2)=(D2^2/D1^2) ((16R/h)/6R/h))=(x^2/16) 6x^2=256 x^2=42.66 x=7 feet |
| each time a x-ray beam scatters, its intensity at 1 m from the scattering object is what fraction of its original intensity | 1/1,000 |
| according to the NCRP, the annial occuapetional whole-body dose-equivalent liit is | 50 mSv |
| name three factors thta have an effecto on patient does | kVp, Ma, inherent filtration |
| the photoelectric effect is more likely to toour with absorvers having a (high/low) z number and (positive or negative) | HIGH/POSITIVE |
| does lukemia exhibit a non linear threshold dose response relationship | no |
| the annial dose limit for medical imaging personnnel inclused radiation from what type of exposure? | occupational |
| name one anomalie thta is possible if an exposure dose of 40 rad were delivered to a pregnant uterus in the third week pregnancy | organ anomaly |
| medical and dental radiation accounts for what % of the general public's exposure ot human made radiation | 90% |
| name two things that are composed of nondividing, diffferniteaded dells? | nurons and neurogila |
| how does filttration affect the primary beam | it increases the average energy of the primary beam |
| what is the min lead requirement for lead aprins, according to thte NCRP | 0.50 mm Pb |
| an OSL dosimeter contains which detector | aluminum oxide |
| immature cells are reffered to as what two names | undifferentiated cells, stem cells |
| what term is used to describe x-ray photonm interaction with matter and the transference of part of the photon's enerfy tp matter | scatteringq |
| what ist the approximate ESE for the average upright PA chest radiograph using 115 kVp and a grid | 20 mrad |
| the annual dose limit for occuapeiorally exposed individuals is vaild for | x-and gamma radiations |
| patient dose increases as fluoro FOV (increases/decreases) | decreases |
| what unit of measure is used to ezpress ionizing raidaiton dose to biologic material | Rem (Sv) |
| What is a method of expressing radiation quialty and a meausr eof the rate at which radiation energy is transferred to soft tissue | LET |
| what would result in the greatest dose to the individual if exposed to 1 rad of ionization?:: external source of 1 MeV x-rays, ext source of diagnostic x-rays, internal source of alpha particles, ext source of beta particles | internal source of aplha particles |
| biologic matreial is least senesitice to irradiation inder what state of oxygination | anoxic |
| a dose of 25 rad to the fetus during the seventh or eight week of pregnancy is likely to cause what anomality | neurologic |
| which three methods can be used to reduce radiation exposure to recently fertilized ovum | elective booking, patient questionarre and the 10 day rule |
| T/F tabletop radiation intensity during fluoro must not exceed 2.1 R/min/mA | t |
| T/F duriong fluoro, table top radiation must not exceed 10 R/min | T |
| In high level fluoro, TT intensity up to 20 R/min is permitted | T |
| name two factors that will affect both the quality and the quantity of the primary beam | HVL and kV |
| diagnostic x-radiation may be described as (high/low) energy, (high/low) LET | low low |
| For radiographic exams of the skull, it is gEnerally preferred that the skull be examined in | The pa projection |
| Accirding to the NCRP, the annual occupationalbdose equivalent limit (50 rem) to the thyroid, skin, and extremities is what in mSv | 500 mSv |
| What is the intensity of scattered radially perpendicular to and 1 m from a patient compared with the useful beam at the patients surface | 0.1% |
| The amount of time that x-rays being produced and directed toward a perpendicular wall is referred to as the | Use factor |
| Which of the folleowinfg results from restriction of the x-ray beam: 1. less scattered radiation production 2. less patient hazard 3. less raduiographic contrast | 1 & 2 |
| which acute radiaiton syumdrome requires the largest exposure before any effects besome apparent | gastrointestinal |
| early symptoms of acute radiation synfrome include what three side effects | leukopenia, nausea and vomiting |
| the most effective tywpe of male gonadal sheileding for use during fluoro is | shaped contact (contour) |
| isotopes are atoms that have the same | atomic number but a different mass number |
| if the ESE for a particular exposure is 25 mrad, what will be the ibntensity of the shcattered beam perpendicular to and 1 m from the patient | 0.025 m rad (reduced by 0.1% 1 meter away) |
| the likelyhood of adcerse radiation effects to any radiographer whose dose is kept below the reccomended guideline is | very remote |
| the automatic exposure device that is located immediately under the x-ray table is the | ionizing chamber |
| the law of Bergonie and Tribondeau states that cells are more radiosensitive if the4y are | highly proliferative and immature |
| the most radiosensitive protion of the GI tract is the | small bowel |
| the photoelectrtic effect is an interaction between an x-ray photon and | an inner-shell electron |
| T/F beam restriction reduces patient dose | t |
| T/F high kVp, low mAs factors help reduce patient dose | t |
| T/F a high speed grid help reduce patient dose | f |
| T/F a high speed imaging system reduces patient dose | t |
| in the production of bremsstrahuling radiation, _____ | the incident electron is deflected wioth resulting enery loss |
| an increase in totla filtration of the x-ray beam will increase | beam HVL |
| the purpose of filters in a film badge is | to measure radiation quality |
| T/F radiation dose to personnel is reduced by exposure cords on fixed equipment must be very shortt | t |
| T/F radiation dose to personnel is reduced by exposure cords on mobile equpiment should be failry long | t |
| T/F radiation dose to personnel is reduced by exposure cords on fixed equipment should be of the coiled, expandable type | f |
| name two body parts that are included in whole-body dose | gonads and blood forming organs |
| T/F irradiation of macromolecules in vitro can result in main-chaincission | t |
| T/F irradiation of macromolecules in vitro can result in cross-linking | t |
| T/F irradiation of macromolecules in vitro can result in point lesions | t |
| irradiation of macromolecules in vitro can result in what three abnormalities | main chain scission, cross linking, point lesions |
| name three examples of late effects ionizing radiations on humans | leukemia, local tissue damage, malignant disease |
| name the most sensitive cells in the body | erythroblasts |
| what are the major effects of DNA irridation | malignant disease, chromosome aberration, cell death |
| what contributes most to patient dose (photolectric effect, compton scatter, classic scatter, thompson scatter) | The photoelectric effect |
| the classifications of actue radaition syndrome incluse all of the following except (CNS, GI tract, neonatal, hematologic) | neonatal |
| in the production of characteristic radiation at the tungsten target, the incident electron | ejects an inner-shell tungsten electron |
| if an exposure dose of 50 mR/h is delivered from a distance of 3 feet what would ve ethe dose delivered acter 20 min at a distance of 5 ft from the source | (I1/I2)=(D2^2/D1^2) (50/X)=(25/9) 25X=450 X=18 Mr/H (60 MIN) |
| name two possible long term somatic effects of radiation exposure | embryologic effects |
| are blood changes possible long term somatic effects of radiation exposure | no |
| the operation of pernola radiation monitoring can be vasei on stimulated luminescence. Which of the collowing personal raidaiton monitors function in that manner? 1.OSL 2. TLD 3. Pocket dosimeter | OSL & TLD |
| if a patient recieved 1,400 mrad during a 7-min fluoro exam, what was the dose rate | (1.4 rad/7 min)=(x rad/ 1 min) 7x=1.4 x=0.2 rad/min |
| biologic material irridated inder hypoxic conditions is | less sensitive thatn when irridated inder oxyginated conditions |
| T/F TLD's are reuseable | t |
| T/F a TLD is a personal radiation monitor | t |
| T/F TLD's use a lithium fluoride phosphor | t |
| T/F after x-ray exposure, TLD's emit heat in response to stimulation by light | f |
| a student radiogra[her who is under 18 years of age must not reciece an annual occupational dose of greater than | 0.1 rem (1 mSv) |
| name one factro that is likely to improve image quality and decreawse patient dose | beam restriction |
| Types of secondary radiation barriers incluse : 1. the control booth 2. lead aprons 3. theh x-ray tube houseing | all |
| what minimum total amount of folitraion (inherent plus added) is required in x-ray equipment operated above 70 kVp. | 2.5 mm Al equivalent |
| a contrilled area is defined as one 1. that is occupied by trained in radiation safety 2. that is occupied by people who wear radiation monitors 3. whose occupancy factor is 1 | all |
| somatic effects resulting from radiation exposure can 1. have possible consequences on the exposed individual 2. have possible consequences on future generations 3. casue temporary infertility | 1 & 3 |
| how does the use of rare earth screens contribute to lowering the patient dose | it permits the use of lower mAs |
| the advuntages of beam restrictions incluse which of the following 1. less scattering radiation is produced 2. less biologic material is iffadiated 3. less total filtration will be necessary | 1 & 2 |
| the dose-response curve that appears to be valid for genetic and some somatic effects is 1. linear 2. nonlinear 3. nonthreshold | 1 & 3 |
| the primery function of filtraion is tp reduce | patient skin dose |
| stochastic effects of radiation are those that 1. have a threshold 2. may be described as "all-or-nothing" 3. are late effects | 2 & 3 |
| what quantity of radiaiton exposure to the reproductive organs is required to cuase temporary infertility | 200rad |
| what personnel radaition monitors will provide an immedaist reading | pocket dosimeters |
| the TT exposure rate during fluoro shall not exceed | 10 R/min |
| if the exposure rate at 3 ft from the fluoro table is 40 mR/h, what will be the exposure rate for 30 min at a distance of 5 ft fromt he table | (I1/I2)=D2^/D1^2 ((40mR/h)/(xmR/h))=25/9 25x=360 x=14.4mR/h so 7.2 mR/h in 30 min |
| if the exposure rate toa body standing 7 ft from a radiation source is 140 mR/h what will be the dose to that body at a distance of 8 ft from the source in 30 min | (I1/I2)=D2^/D1^2 ((104/x))=64/49 64x=6860 x=107mR/h, and 53.6 mR/30 MIN |
| which of the following types of radiation is considered electromagnetic 1. x-ray 2. gamma 3. beta | 1. X ray 2. gamma |
| radiation output from a diagnostic x-ray tube is measured in what units of meausrement | roentgen |
| which of the following are considered espeically radiosensitive tissues? 1. bone marrow 2. intestinal crypt cells 3. erythoblasts | all |
| which of the following safegards are taken to prevent inadvertent irradiation in early pregnancy 1. patient postings 2. patinet questionnare 3. elective booking | all |
| according to the NCRP, the pregnant radiographers gestional dose equivalent limit for a 1-month period is | 0.5 mSv |
Created by:
amanda.clark