Why is aluminum used for Xray beam filtration?
Beryllium is commonly used in mammography (which use low-energy photons) as it provides very little filtration. Other types of x-ray generally use aluminum, copper or tin. This is due to the loss of lower energy photons from a polychromatic beam. The average x-ray energy is increased and becomes more penetrating 6.
What does the aluminum filter remove?
The purpose of the aluminum filter is to remove the low-energy, long-wavelength, least penetrating x-rays from the beam. X-ray machines operating at 70 kVp or greater must have aluminum filtration of 2.5 mm.
Can X rays pass through Aluminium?
Of course X-rays can penetrate aluminium and produce an image through the same, but the KV (power of the generated radiation) must be sufficient to penetrate the thickness of aluminium. Aluminium has the property to slow and refract X-ray.
Which material is used to make the filter in an X ray machine?
aluminium
What is used to direct the Xray beam?
or cone, appears as an extension of the x-ray tube head and is used to direct the x-ray beam.
Which tissue has the highest radiation sensitivity?
Amongst the body cells, the most sensitive are spermatogonia and erythroblasts, epidermal stem cells, gastrointestinal stem cells. The least sensitive are nerve cells and muscle fibers. Very sensitive cells are also oocytes and lymphocytes, although they are resting cells and do not meet the criteria described above.
What type of radiation is produced when electrons strike a metal target?
x-rays
What is secondary radiation?
Secondary radiation refers to radiation originating from the absorption of previous radiation in matter. It may be in the form either of electromagnetic waves or of moving particles.
What is the major advantage of automatic film processing?
What is the major advantage of automatic film processing? Time and temperatures are automatically controlled. less space required. How often should the levels of solution in the automatic processor be checked?
Which is the most widely used form of processing solution?
liquid concentrate processing solution
What are the three methods of film processing?
Film processing, whether it is manual or automatic, comprises five basic steps: (1) developing, (2) rinsing or stop bath, (3) fixing, (4) washing, and (5) drying. The first step in learning how to process a film is a basic understanding of the processing solutions.
How does a film holder protect the patient from unnecessary radiation?
How does a film holder protect the patient from unnecessary radiation? It keeps the patient’s hands and fingers from being exposed to x-radiation. Describe a basic type of image receptor. Bite-block with a backing plate and a slot for film-sensor retention.
What is the purpose of using a position indicator device PID?
Dental x-ray machines conventionally are equipped with a position indicating device, (formerly commonly called a cone, or tube, and more recently called a position indicating device or PID) that is used to both limit the size of the useful x-ray beam employed in exposing the x-ray film located within the patients mouth …
What are the five basic sizes of intraoral dental film?
Intraoral film packets come in five basic sizes:
- Child (size 0)
- Narrow anterior (size 1)
- Adult size (size 2)
- Preformed bite-wing (size 3)
- Occlusal (size 4)
What exposure controls contrast?
What exposure factors control contrast? kVp = Higher kilovoltage produces more penetrating radiographs and lower radiographic contrast. What is meant by density? Density is the overall blackness or darkness of a film.
What are the 4 primary exposure factors?
Primary Exposure Factors
| Question | Answer |
|---|---|
| what are the 4 primary exposure factors | *ma *kVp *time *SID |
| mA x time= | mAs |
| what is the k shell binding energy for bone | 16 |
| what does mA control | quantity of radiation/density/brightness |
What is the primary controlling factor for contrast?
Stack #132647
| Question | Answer |
|---|---|
| What is the difference between adjacent densities within the radiographic image? | radiographic contrast |
| What is the primary controlling factor for contrast? | KVP |
| What are the two types of contrast seen in medical radiography? | Long scale (low contrast), Short scale (high contrast) |
What two factors affect subject contrast?
Subject contrast is caused by the range of absorption of radiation by the subject, i.e., the material being radiographed. This is affected by (a) the mass of the subject, including the atomic number and the thickness, and (b) the penetrating power of the radiation source, which is the wavelength of the radiation used.
How does kVp and mAs affect image quality?
The first experiment showed that, when the film density is kept constant, the higher the kVp, the lower the resolution and image contrast percentage; also, the higher the mAs, the higher the resolution and image contrast percentage.
How does Sid affect contrast?
Increasing the SID decreases the amount of unsharpness and increases the amount of recorded detail because as the distance between the source and IR increase, the diverging x-rays become more perpendicular to the object imaged.
What happens when kVp is increased?
The higher the kVp, the more likely the x-ray beam will be able to penetrate through thicker or more dense material. Low kVp photons are weak and easily absorbed by body tissues or filters that have been placed.
What is the 15 kVp rule?
The 15% rule states that changing the kVp by 15% has the same effect as doubling the mAs, or reducing the mAs by 50%; for example, increasing the kVp from 82 to 94 (15%) produces the same exposure to the IR as increasing the mAs from 10 to 20.
What are the advantages of using high kVp techniques?
The use of high kVp and low mAs techniques will reduce the dose to the patient. Higher kVp results in more free transmission, therefore the patient is absorbing less of the dose. Increasing the kVp by 15 percent will double the density in the radiograph and reduce patient dose in comparison to doubling the mAs.
Is kV the same as kVp?
One standard way to measure pulsating DC is its peak amplitude, hence kVp. Most modern X-ray generators apply a constant potential across the x-ray tube; in such systems, the kVp and the steady-state kV are identical.
What does kVp and mAs mean?
Along with the mAs (tube current and exposure time product) and filtration, kVp (tube voltage) is one of the primary settings that can be adjusted on x-ray machines to control the image quality and patient dose.
Is mAs a quality or quantity?
As mA increases so does the number of electrons. mA is directly proportional to the tube current. mAs is the primary controller of x-ray quantity.
How is kVp calculated?
(measured thickness in centimetres x 2) + 40 = initial kVp For example, if your dog measures 14cm thickness at the 12th rib, the initial kVp should be 68.
What is high kVp technique?
Image quality Particularly in larger body parts, such as obese adult torsos, lower energy photons are absorbed completely without contributing to image formation. In such situations, higher kVp is employed to improve the x-ray intensity reaching the receptor, thus increasing the signal to noise ratio on the images.
What happens to density as Sid increases?
As SID increases, intensity of the beam decreases. A 20% change in SID will cause a visible difference in density. We use the inverse square law to calculate the difference between distance and density. When SID is doubled, the density will decrease by a factor of 4 (will be 1/4 the original).
How does Sid affect image quality?
The source image receptor distance known as the SID is the distance of the tube from the image receptor, affecting magnification. The greater the SID, the less magnification the image will suffer.