Key differences analog vs digital radiography

In the next table three X-ray technologies – analog (film based), Computed Radiology (CR) and Direct Digital Radiology (DR) - are compared on key aspects.

X-ray Characteristics Film CR Direct Digital/DR
Computer aided detection for TB no yes yes
Low dose - high image quality no yes/no yes
Images per hour 30 30 60
Image cost (estimate per throughput) 3,50-4,50 1,50-2,50 1,00-2,50
Immediate image availability no no yes
Image transfer over mobile phone network no yes yes
Data management tools no yes yes
Consumables elimination no no (plates) yes
Analog X-ray Direct Digital X-ray
insufficient expert staff on site to interpret teleradiology and computer aided detection possible
ordinary X-ray machines use higher dose new flat panel detectors allow lower dose
need to repeat X-ray due to low quality of images constant quality as Automatic Exposure Control s/w eliminates mostly the need to repeat X-ray
only one local hard copy easy availability also in the Cloud for quality control and research
poor image quality consistent high quality image
film development errors cause useless images no developing needed
delay between X-ray exposure and image availability image immediately available
(also via mobile phone network / internet)
image archiving not centralized, at times inaccurate easy storage and instant access to archived images, automatic backup possibility
chemical waste causes environmental damage clean technology, no film no chemicals needed; can operate on batteries and solar power

Digital X-ray

Digital Radiology technology fit for low and medium resource areas is to be designed as a: “single phase (220V), solar powered system and easy to use in the field; a system that allows to make, store, and diagnose CXRs from anywhere and can cope with high ambient temperatures and humidity"

Latest technology can ensure low dose for the patient and instant high quality images for the medical doctor or radiologist. A DR system includes a workstation for diagnosis and an archive server. Integration with archive and viewing software makes the system suitable for fast and efficient medical use. Image reading can be done immediately on the diagnostic monitor, or at any location in the world by sending a compressed image to a centre with qualified staff to read radiographs. A daily throughput of more than 300 images can be achieved per system.

Maintainability in the field is generally high if the X-ray unit comprises components that can be swapped easily. In addition components have to be engineered for shock resistance and the system is to be supported by rubber shock absorbers. Remote system testing using internet and built in test equipment can indicate any component to be replaced or serviced.

Basic digital radiology system technical characteristics

Commonly used for mobile and stationary use


  • Single arm Design of Tube and Detector with motorised height adjustment and the ability to rotate the arm to accommodate exposures on standing, seated and recumbent patients
  • Fixed focus-detector distance between 140 cm minimum and 155 cm maximum
  • Direct digital system with throughput capacity: of at least 60 images per hour
  • Capacitor x ray generator, recharge of the condenser in maximum 3 sec. for high throughput
  • Single phase 220/240 VAC mains input to allow for connection to national grid and in case of back-up power for the use of solar panels recharged batteries
  • Mobile internet connectivity
  • CE certified system, delivered with set of manuals


  • Input power 220 VAC 8/16 A (single phase connectable to national grid and to batteries/inverter)
  • Output power 50 KW (125 KV @ 630 mA)
  • Integration with flat panel detector, one touch panel for both X-ray setup and review
  • kV range 40-125
  • mA range 10-630
  • mAs range 0.1-630
  • AEC integration mAs 01 to 500 mAs shortest exposure time min 1 ms
  • X-Ray tube should be a IEC Classification Class I Type B or better
  • Temperature range 0 °C ÷ 40 °C
  • Rel humidity range 10% ÷ 90%, non-condensing


  • Suitable for chest X-ray and general radiographic examinations (such as abdomen & extremities)
  • Min detector size 43 x 42 cm
  • Scintillator & amorphous silicon (a-Si)
  • 5.9 megapixels min Gray scale: 12 bits minimum 4000 levels
  • Calibration of the detector less or equal - once per year
  • Max weight 5 kg
  • Pixel size min 160x160 μm
  • A/D 14 bit
  • Non moving grid, grid elimination software
  • Preview time 3-6 seconds after X-ray exposure
  • Non moving grid with GRID removing software
  • DICOM 3.0 compatible
  • Integration with X-ray generator, one touch panel for best quality X-ray at lowest possible dose


  • Touch screen operation, Size min 15”
  • Windows 10
  • Min processor capacity I3, 8GB RAM, 1TB HDD (RAID 1)

First installations in-country are recommended to be done by factory trained engineers.

3 steps to detect a patient with presumptive TB

The imaging process: Software when designed with the input of users and radiology specialists warrants an intuitive user interface. Most user interfaces are Windows™ based and appear similar to well-known applications.

Making an image: First, patient demographic information is entered by the keyboard, scanner or DICOM Modality Worklist. Second, the image is taken. The Automatic Exposure Control will give high quality Chest X-rays with the lowest possible dose for the client.

Diagnosing everywhere: Immediately after the image appears on the screen it can be relayed to any central database anywhere in the world and is typically available just three seconds after the exposure has been made. When using the mobile phone GSM network sending a compressed 350KB image to a diagnostic centre will take about 35 seconds provided image compressing and communication software is used.