As an alternative to X-Radiography, Gamma Radiography is widely used for applications where X-Ray is impractical. This could be due to access restrictions or material thickness when a more penetrating method is required.

Frazer Nash NDT Ltd store two Techops 660B containers containing Selenium 75 Isotopes. Selenium is becoming much more widely used than Iridium 192 due an improved quality of radiographs and safer working conditions for NDT personnel.