TCDHA RAD THEORY - WEEK 1&2
SET QUESTIONS |REVISION STUDY
MATERIAL 2025\26
Thyroid collar - ACCURATE ANSWERS✔✔ flexible lead shield
-protect the thyroid gland from scatter radiation.
Lead apron - ACCURATE ANSWERS✔✔ a flexible lead shield
-to protect the patients reproductive and blood forming tissues from
scatter radiation
Inherent filtration - ACCURATE ANSWERS✔✔ primary beam passes
through glass window, oil bars and tube head
- 0.5 to 1.0mm aluminum
Added filtration - ACCURATE ANSWERS✔✔ FILTERS OUT LONG
WAVELENGTHS W LOW ENERGY AND SOFT RADIATION
Aluminum discs in the path of X-ray beam
Total filtration= -1.5mm below 70kvp
-2.5mm above 70 kvp
,Collimator - ACCURATE ANSWERS✔✔ restricts size and shape of X-
ray beam
Circular- beam= 2.75in d
Rectangular- exposes 60% less tissue
Primary radiation - ACCURATE ANSWERS✔✔ -useful beam
Penetrating xray beam that exits tube head
Secondary radiation - ACCURATE ANSWERS✔✔ created when the
primary beam interacts with matter
Scatter radiation - ACCURATE ANSWERS✔✔ A form of secondary
radiation
-when an x-ray beam has been deflected from its path by interaction
with matter
Insight film (F-speed) - ACCURATE ANSWERS✔✔ -fastest intraoral
film
-20% reduction on exposure over E-speed
-film holding devices are used
-limits x radiation received
EXAMLINKS
STUDY SMART,
, Radiographer protection - ACCURATE ANSWERS✔✔ -stand 6ft away
at 90-135 degree angle to X-ray beam
Leakage radiation - ACCURATE ANSWERS✔✔ radiation that emits
from tube head
-excluding primary beam
What is maximum permissable dose (MPD)? - ACCURATE
ANSWERS✔✔ dose you can receive in a specific period of time
-radiation the body can endure with little/no injury
MPD for occupationally exposed - ACCURATE ANSWERS✔✔ 5.0
rem/year (0.05Sv/year)
MPD for non-occupationally exposed persons - ACCURATE
ANSWERS✔✔ 0.1 rem/year
(0.001Sv/year)
EXAMLINKS
STUDY SMART,
SET QUESTIONS |REVISION STUDY
MATERIAL 2025\26
Thyroid collar - ACCURATE ANSWERS✔✔ flexible lead shield
-protect the thyroid gland from scatter radiation.
Lead apron - ACCURATE ANSWERS✔✔ a flexible lead shield
-to protect the patients reproductive and blood forming tissues from
scatter radiation
Inherent filtration - ACCURATE ANSWERS✔✔ primary beam passes
through glass window, oil bars and tube head
- 0.5 to 1.0mm aluminum
Added filtration - ACCURATE ANSWERS✔✔ FILTERS OUT LONG
WAVELENGTHS W LOW ENERGY AND SOFT RADIATION
Aluminum discs in the path of X-ray beam
Total filtration= -1.5mm below 70kvp
-2.5mm above 70 kvp
,Collimator - ACCURATE ANSWERS✔✔ restricts size and shape of X-
ray beam
Circular- beam= 2.75in d
Rectangular- exposes 60% less tissue
Primary radiation - ACCURATE ANSWERS✔✔ -useful beam
Penetrating xray beam that exits tube head
Secondary radiation - ACCURATE ANSWERS✔✔ created when the
primary beam interacts with matter
Scatter radiation - ACCURATE ANSWERS✔✔ A form of secondary
radiation
-when an x-ray beam has been deflected from its path by interaction
with matter
Insight film (F-speed) - ACCURATE ANSWERS✔✔ -fastest intraoral
film
-20% reduction on exposure over E-speed
-film holding devices are used
-limits x radiation received
EXAMLINKS
STUDY SMART,
, Radiographer protection - ACCURATE ANSWERS✔✔ -stand 6ft away
at 90-135 degree angle to X-ray beam
Leakage radiation - ACCURATE ANSWERS✔✔ radiation that emits
from tube head
-excluding primary beam
What is maximum permissable dose (MPD)? - ACCURATE
ANSWERS✔✔ dose you can receive in a specific period of time
-radiation the body can endure with little/no injury
MPD for occupationally exposed - ACCURATE ANSWERS✔✔ 5.0
rem/year (0.05Sv/year)
MPD for non-occupationally exposed persons - ACCURATE
ANSWERS✔✔ 0.1 rem/year
(0.001Sv/year)
EXAMLINKS
STUDY SMART,
