Module 4 Flashcards
Equivalent Dose (HT)
Allows the different Radiobiological effectiveness (RBE)
comparison
Radiation weighting factor WR
represents different the biological effects of different
radiations on different tissues
Tissue weighting factor WT
Conversion of dose to specific area to whole body
Bitewing/Periapical Dose
0.0003 – 0.022 mSv
Panoramic Dose
0.0027-0.038 mSv
Upper standard occlusal Dose
0.008 mSv
Lateral Cephalometric Dose
0.0022-0.0056 mSv
Collective dose
effective dose (E) x population
Dose Limit Classified worker
20mSv
Dose Limit Non Classified worker
6 mSv
General Public Dose Limit
1 mSv
Risk Factor intra oral films traditional
1 fatal cancer in every 2 million
Risk Factor intra oral film recommended equipment
1 fatal cancer in every 20 million
Risk Factor panoramic radiograph
1 in 1,000,000
Direct Action (Damage)
Energy from ejected electron (photoelectrons)
or the x-ray photon is transferred to the cells
DNA, RNA or protein enzymes
Indirect Action
Most common reaction as 80% of our body consists of water When radiation hits the water molecules Ionisation occurs. This produces ions and free radicals.
Deterministic Effects
Will definitely happen from a specific high
dose of radiation
Stochastic Effects
Every dose has the possibility, No safe dose or level
Genetic Effects
Gene or chromosomes mutate can be can be
spontaneous or caused by radiation, no threshold dose
When is the most sensitive time for a unborn child?
3-7 weeks
