8 November 1895, produced and detected electromagnetic radiation in a wavelength range today known as X- rays or Röntgen rays, electromagnetic radiationwavelengthX- rays an achievement that earned him the first Nobel Prize in Physics in 1901.Nobel Prize in Physics BORN-Wilhelm Conrad Röntgen 27 March 1845 Lennep, Rhine Province,Germany LennepRhine ProvinceGermany DIED - 10 February 1923 (aged 77) Munich, Germany Munich RADIATION PHYSICS - 2

Specific learning Objective To know about the components of X-ray tube To know about the electricity specification of Xray machine. To know about transformer and its type.

FORMAT  Introduction  Components of X-ray Tube head  Electricity specification  Transformer  Auto transformer  Step Up and Step Down Transformer  Effect of mA, Kvp and exposure time on Xray beam

Tube head support arms control panel

OIL STEP DOWN TRANSFORMER STEP UP TRANSFORMER

+ 110, , 220 positive negative 0 Direct Current (Constant Potential): 800 cycles/sec. 60-cycle Alternating Current ALTERNATE CURRENT (AC) MACHINE- SELF OR HALF WAVE RECTIFIED INVERSE VOLTAGE OR REVERSE BIAS DIRECT CURRENT (DC) MACHINE - FULL WAVE RECTIFIED

Number of Impulses 60 = 1 Second 30 impulses/60 = 0.5 second 15 impulses/60 = 0.25 second 1/60 60 impulses/60 = 1.0 second

- + X-ray Production + - 8mA 70Kvp LOW VOLTAGE CURRENT – 8 Ma – for tungsten filament HIGH VOLTAGE CURRENT – 70 Kvp – for potential difference between cathode and anode

Transformers Electromagnetic devices that allow a voltage of alternating current to be changed.  Principle operation of a transformer is based on induction. When current is passed through a conductor, a magnetic field is established in and around the conductor. This magnetic field can be used to induce a voltage and current flows in a conductive material that is placed close by.

Step-Down Transformer Primary Secondary 110 volts current flow 3-5 volts current flow LOW VOLTAGE CURRENT

110 V 65 V current flow Autotransformer 80 V

Step-Up Transformer Primary Secondary 110 volts current flow 65,000 to 90,000 volts current flow

mA (milliamperes) X-ray Energy (keV) Number of X-rays mA 5 mA maximum energy average energy (no change) ↑QUANTITY

Exposure time X-ray Energy (keV) Number of X-rays 70 1 sec 0.5 sec maximum energy average energy (no change) ↑QUANTITY

Increasing mA or Exposure Time ( E.T) results in: An increase in the number of x-rays produced No change in the energy of the x-ray beam milliamperes (mA) x seconds (s) = mAs 10 mA x.5 seconds = 5 mAs 20 mA x.25 seconds = 5 mAs ↑mA → ↑electrons → ↑x ray photon → ↑ quantity of Xrays ↑ E.T → ↑electrons → ↑x ray photon → ↑ quantity of Xrays

kVp (kiloVolt peak) X-ray Energy (keV) Number of X-rays kVp 70 kVp maximum energy average energy ↑Kvp → ↑speed of electron →↑energy of Xray photon →↑ penetration ↑ QUALITY

Incorrect exposure factors (too many x-rays or too much energy; -film too dark) Correct exposure factors -Good density Incorrect exposure factors (not enough x-rays or energy too low; -film too light)

Constant patient size 1.Proper kVp, mA, exposure time ( e.t. ) 2.Increase mA; no change in kVp, e.t. 3.Decrease e.t.; no change in kVp, mA 4.Increase kVp; no change in mA, e.t. 5.Double mA, halve e.t.; no change in kVp ACB B A C A B