Non-recurring:

(a)Basic portable X-ray machine(b)X-ray protection devices (e.g. lead aprons, Gloves, Goggles)(c)X-ray monitoring badges(d)X-ray film storage box(e)Different sized X-ray film cassettes (e.g. 8X10”, 10X12”, 12X15” etc)(f)Different types Grid (e.g. 5:1, 8:1, 12:1 as per grid ratio)(g)Different sized X-ray film hangers (At least 4 per size)(h)Different sized lead blockers(i)Lead markers (e.g. Alphabets and numbers)(j)Animal positioning devices(k)Safe lights (Usually low wattage red lights)(l)Film processing tanks(m)Film drier(n)X-ray film viewer/illumination box(o)X-ray record keeping files

Recurring:

(a)Different sized X-ray films(b)X-ray film developer, replenisher and fixing agents.(c)Intensifying screen cleaning solution(d)Contrast media (e)Tranquilizers/sedatives(f)Anaesthetic agents(g)Emergency drugs/items stock(h)Animal restraining basic devices

Fixed type: Ceiling suspended or floor mounted Mobile type

Portable type Ultra portable (Dental)

Fluoroscopy CT

Digital radiographyPlain and computed radiography

X-ray cassettesX-ray cassettes X-ray gridsX-ray grids

X-ray films in light-proof boxesX-ray films in light-proof boxes

Lead markersLead markers

X-ray automatic processorX-ray automatic processor

X-ray processing tanks

Dry imager and printer

X-rays may be produced when a beam of electrons of sufficient energy from cathode interact with anode matter inside the X-ray tube.

The heat of cathode filament is directly proportional to the magnitude of the current beam (mA) passed through it.

Thus more is the ma, the more will be the heat and more will be the number of electrons released from filament atoms.

The more is the number of available electrons to interact with the target, more will be number of X-rays produced

Another way to control the number of electrons is to increase the time for which machine is operated. This is controlled by another knob on the control dial which select the time (S).

The kinetic energy of electrons travelling from cathode to anode in the X-ray tube is dependent on the applied KVP.

The higher is the KVP, the higher will be energy of electrons and

The higher is the energy of incoming electrons, the higher will be the energy of resulting X-ray photons.

X-rays are directed for a brief period of time in a defined angle towards the body part to be examined radiographically.

An X-ray sensitive film in a light proof cassette is kept on the other side of part to catch those X-rays that are able to penetrate the part.

The X-rays are differentially absorbed in body tissues through an interaction known as

photoelectric absorption.

Thus its primary beam gets attenuated and reach the X-ray film carrying useful information about the composition of the body part exposed.

X ray film in light-proof cassette

AirAir

BoneBoneSoft tissue

• Highest absorption

• Intermediate absorption

• Lowest absorption

The X-ray film gets selectively modified by these X-rays* depending upon the number of X-rays reaching to its

different parts thus forming a ‘LATENT IMAGE’ of the part being exposed.

*X-ray films are in fact mostly exposed by the light rays emitted by the intensifying screen fitted inside the cassette. (The intensifying screen convert X-rays in to light.)

Such modified X-ray film can be chemically processed to convert this latent image in to a visible one.

The parts of AgBr grains where metallic silver atoms have been deposited is more vulnerable to the action of reducing solution.

Here the Ag ions readily acquire electrons from the developing solution and converts in to black metallic silver.

In the fixing and clearing solution, the part of emulsion containing metallic silver is fixed and unaffected AgBr grains are solubilized and removed.

Thus area of X-ray film receiving greater number of X-rays (or light rays) turn blacker than other; the area of film not receiving the X-rays turns transparent.

When viewed against white light, the transparent area appears white.

Accordingly a grayish image forms over radiograph depicting the details of the section of the part exposed.

Thus on a radiograph bone looks whitish, lungs look blackish and the rest of the soft tissue appears in shades of gray.

Minimum magnification of the image of structures being examined (FFD and subject film distance)

Least possible distortion of the same (Patient positioning and X ray beam angles)

Sharp delineation of the structures (kVp, mAs, patient restraining, use of grid, processing of film)

Adequate contrast (kVp, mAs, processing of film)

Sufficient radiographic density (kVp, mAs, processing of film)

Necessary numbers of radiographic views

Additionally required contrast techniques

Absence of radiographic artifacts and processing faults (Quality of X ray accessories, processing and storage of films)

Formulation of radiographic technique chartFormulation of radiographic technique chartThickness of part (X) in cms

Suggestive kVp

Up to 80 kVp 80-100 kVp Above 100 kVp

X-3 A-6 A-9 A-12

X-2 A-4 A-6 A-8

X-1 A-2 A-3 A-4

X A A A

X+1 A+2 A+3 A+4

X+2 A+4 A+6 A+8

X+3 A+6 A+9 A+12

• *A is the kVp that provided best radiographic quality on trial exposures. • ** Mas is to kept constant as per the best combination on trial exposures• *** This technique chart will be applicable for similar kind of tissues only.

kVp change required with change in mAskVp change required with change in mAskVp range kVp change required when mAs is doubled or halved

Doubled Halved

41-50 -4 +4

51-60 -6 +6

61-70 -8 +8

71-80 -10 +10

81-90 -12 +12

91-100 -14 +14

101-110 -16 +16

mAs change required with use of gridGrid ratio Increase required in mAs by a factor of

5:1 2

8:1 3

12:1 4

Exposure latitudeExposure latitudekVp range

Exposure latitude

46-55 ±2 kVp56-65 ±4 kVp66-75 ±6 kVp76-85 ±8 kVp86-95 ±10 kVp

Degree of variation from the correct exposure factors that still produces a diagnostic radiograph.

Degree of variation from the correct exposure factors that still produces a diagnostic radiograph.

Thumb rules•Use higher kVp•Use highest possible mA•Use shortest possible exposure time (s)•Use constant FFD (90-100 cms.)

Processing solution tanks

A: Developing solution tankB: Rinsing solution tankC: Fixing solution tankD: Washing (running water) tankE: All enclosing warm water (~200 C) tank

Processing solution tanks

A: Developing solution tankB: Rinsing solution tankC: Fixing solution tankD: Washing (running water) tankE: All enclosing warm water (~200 C) tank

Off to drierOff to drier

BA C DE

5 min5 min1/2 min1/2 min

10 min10 min20 min20 min

Timings are suggestive only

12 mAs, 16 mAs, 20 mAs, 24 mAs kVp constant at 75 12 mAs, 16 mAs, 20 mAs, 24 mAs kVp constant at 75