Radiography Calculations

Re: Radiography Calculations

Nick Shackleton — Thu, 08 May 2014 20:37:53 GMT

[quote user="Lynsey MacKay"]

Hi,

There is a Radiography Triangle formula. MAS with MA and S underneath.

When given the MAS and MA to work out the seconds you divide the mas by ma.

When given MAS and S, divide the mas by the seconds to work out the MA

& when given the MA and S to work out the MAS you simply times the two figures :)

Hope that helps or makes sense!

[/quote] This is only how you calculating s, mA or mAs using two of te other figures

Re: Radiography Calculations

Lynsey791 — Thu, 01 May 2014 22:33:33 GMT

Hi,

There is a Radiography Triangle formula. MAS with MA and S underneath.

When given the MAS and MA to work out the seconds you divide the mas by ma.

When given MAS and S, divide the mas by the seconds to work out the MA

& when given the MA and S to work out the MAS you simply times the two figures :)

Hope that helps or makes sense!

Re: Radiography Calculations

Stuart Ford-Fennah — Tue, 01 Apr 2014 16:01:02 GMT

Hi,

Im nor radiogrpaher or been trained in nuclear medicien but I think the formulae your looking for could be for energy:
E = kV x mA x exposure time(seconds)
This will give the energy in joules as long as the exposure time is in seconds. This is from memory so i would strongly advise you check this as im not 100% sure

There is a more complicated formulae for calcualting exposure but i think as Nick mentioned in earler posts it has many factors to in put and relies on you knowing densitys and some more complex figures

Hope this helps a little anyway

Re: Radiography Calculations

Samantha Tanfield — Tue, 01 Apr 2014 13:14:01 GMT

HI, thanks for your reply, but trainee VN's need to know how to calculate exposures. There is a formula, but I just can't find it!!

Re: Radiography Calculations

Nick Shackleton — Mon, 31 Mar 2014 20:30:14 GMT

As a general rule in chest radiography a high kV is used with a low mAs. This improves the contrast between the structures of the thoracic cavity. Whereas with abdominal radiography you should use a lower kV with a longer mAs. This gives better differential between the various structures within the abdominal cavity.

Re: Radiography Calculations

Nick Shackleton — Mon, 31 Mar 2014 20:11:45 GMT

All X-ray generators vary ever so slightly so who ever supplied you with you machine should of provided a sample exposure chat. There are other calculations that you need to know such as inverse square rule and the 10kv rule.... So many other factors involved too. Not just a case of doing a calculation. Factors include FFD, filliment size cassette type, whether you're using CR or DR or still using film. Use of a grid or Bucky.....