Angiographic facilitiesTortorici Chapter 11

Designed around exam table500 sq feet min. (25 x 20)60 sq feet in control room Wide doors, (multiple)Ample cabinets/counters Fluorescent & incandecent lights on dimmer

O2SuctionCrash CartSinksPhonesSurgical LampApron storage

Angio Suite

Control room

Bi-plane C-arms

Control room

Cath Lab

Cath Lab

Peripheral LabSterile

set-up

Dirty Utility

Elevators

FilmFiles

MedicalDirector

Specials labSupervisor

Reading Room

Private Consult

EmployeeLounge

Recovery

Outpatientreception

Outpatientwaiting

Darkroom

Restrooms

Changingrooms

Storage

Multi-FormatCameras

Nurses’Office

Cath labSupervisor

Waiting/Recovery roomsOfficesStorage/UtilityNear Surgery

Generators and Tubes

Generators (Film or digital)

1000 mA

3 phase or high frequency (constant potential)

Tubes

High heat capacity (6/sec. for 5 s., or, for cine up to 60 a second)

.3 and 1 mm focus (fractional focus)

Smaller anode angle (7-10o instead of 17-20o)

Faster rotors (10,000+ instead of 5,000)

Anode heat Formula

kVp x mAs x generator factor(times number of exposures)

Generators and Tubes

Magnification radiography

How is it done?What happens to detail?How is detail improved?Magnification formula

SODSID

OIDObject sizeMag factor% magnification

SID = Image WidthSOD = Object Width

40” = 5” 20” = X

Object size = Mag factor = % magnification =

2.5”2X

100%

How a Fluoroscopic Image Gets Intensified and Digitized

1. X-rays pass through the body or are attenuated, thus capturing a pattern of the parts they pass through.

From the X-ray tube

2. X-rays excite atoms of fluorescent screen, light is given off. This is fluoroscopy in its simplest form but the image is very dim.

3. Light stimulates a photoemissive material to liberate electrons. Image pattern is maintained

4. Electrons are accelerated toward a tiny fluorescent screen at other end of image intensifier. Concentration of electrons and added kinetic energy make image tens of thousands of times brighter.

5. Optical lens focuses light

6. Video camera (old) or CCDmicrochip, like in homecamcorders)translates image into electrical(video) signal

7. Computer assigns pulses from video signal values in binary code (0s and 1s) and stores them as image data

Video signal

8. Displayedon monitor

Video signalImageIntensifier

Cine film. For heart studies, 35mm filming of multiple projections of the coronary arteries and left ventricle.

Most institutions have gone digital, butmany will still have cans of film and a cineprojector stashed in an archive.

A C-arm fluoroscope

Image intensifier

X-ray tube

Cine camera

Patient table

Videocamera

A C-arm fluoroscope

Image intensifier

X-ray tube

Cine camera

Patient table

Videocamera

Cameras or “Pickup Tubes”

* Vidicon (standard fluoro)

* Plumbicon (better contrast, less lag, but more mottle)

CCD Image Intensifiers

Lightweight

Fast movements

Photoelectric detectors embedded in layers of silicon

Each pixel is 6 to 25 microns in size, and can store 10,000 to 50,000 electrons.

1. If an object is radiographed at 40” SID and an OID of 12”, what is the magnification factor?

2. A 3400 RPM rotating anode is employed to maximize heat dissipation in an angio x-ray tube.

3. If the linear magnification is 1.6, what is the area magnification?

4. The anode of a typical angiographic x-ray tube should have an angle no larger than:

5. The most efficient x-ray generator, and the one best suited to the demands of arteriography is:

6. The recommended focal spot size for performing magnification arteriography is:

7. If 12 exposures are made at 75 kVp, 500 mA, 100 ms on a 3 phase, 12 pulse unit, how many heat units are produced? 8. Which of the video pick-up devices has the least amount of lag time?