A shielding plan is a document which details the level of shielding that is, or will be, installed in order to protect workers and members of the public. This could include dental, veterinary, chiropractic, or other medical premises where ionising radiation apparatus is used. The plan will typically include floor plans, estimated dose calculations and other details related to radiation protection.
Where a radiation source is used it is a requirement that radiation shielding be documented as part of commissioning and where shielding modifications are made subsequent to commissioning.
Any source that will be installed in new or renovated premises must have a radiation shielding plan prepared and submitted with the registration application. Where a replacement source is installed into existing premises which have not been renovated submitting a copy of the existing shielding plan will generally be sufficient.
To ensure that the shielding plan meets all relevant requirements, it should be submitted as early as possible and prior to construction. The radiation shielding needs to be inspected by HPS during the construction phase before it is covered by paint, plaster, floor coverings or other fittings – or must be tested by accredited testers.
Any penetrations to the shielding, such as for cables, power points, water pipes or light switches, need to be addressed with material equal to or greater than the lead equivalence of the material which was removed.
The additional material needs to extend beyond the edges of the penetration by at least twice the offset distance*. If the location of a stud or nogging makes this impossible the additional material must return along the stud or nogging to meet the original layer of material.
*The offset distance is the distance between the original material and the additional material.
The Radiation Council may request third party verification of installed shielding when considering a source registration application or re-application (renewal).
For further information contact the Health Protection Service, and consult the following documents: National Directory for Radiation Protection, June 2017 (RPS 6), Radiation Protection in Planned Exposure Situations (2016) (RPS C-1), Fundamentals for Protection Against Ionising Radiation (2014) (RPS F-1), and any relevant RPS publication, e.g. Code of Practice for Radiation Protection in the Medical Applications of Ionizing Radiation (2008) (RPS14). The National Council on Radiation Protection and Measurements (NCRP) Report No. 147, Structural Shielding Design for Medical X-Ray Imaging Facilities may also be useful.
Following a decision made by the ACT Radiation Council, in a move towards national uniformity, please note the following design constraints which should now be used in radiation shielding calculations:
- Controlled areas 2mSv/yr (40µSv/wk)
- Other areas 0.5mSv/yr (10µSv/wk)
A controlled area, in relation to a radiation source, is a limited access area:
- in which the exposure of persons to radiation is under the supervision of an individual in charge of radiation protection. This implies that access, occupancy and working conditions are controlled for radiation protection purposes; OR
- to which access is subject to control and in which employees are required to follow specific procedures aimed at controlling or monitoring exposure to radiation.
If a blanket design constraint is used for an entire practice or department then this should be 0.5mSv/yr (10µSv/wk).
Shielding design height requirements from the finished floor level are:
- no less than 2.1m for general radiography, fluoroscopy, mammography, BMD/DEXA, OPG, intraoral, dental CBCT and nuclear medicine; and
- no less than 2.7m or to the upper slab, whichever is the lower for CT, including SPECT/CT, PET/CT and all other non-dental CBCT unless a lower height has been authorised by the Radiation Council.
However, for high dose areas including CT and interventional radiology, shielding design depends on a number of site-specific factors so shielding designers are asked to refer to authoritative texts which deal with these cases such as  and to specify height requirements greater than those indicated above, where applicable.
 Sutton, D.G., Martin, C.J., Williams, J.R., Peet, D.J., Radiation Shielding for Diagnostic Radiology, 2nd Edition, British Institute of Radiology, London (2012).
Alternative shielding materials
It has come to the attention of the ACT Radiation Council (the Council) that some shielding designers have been specifying this as an alternative shielding material. Submission of a shielding plan which includes the specification of this material may result in the Council requesting supporting information in relation to the X-ray attenuation properties of the material. The supporting information must be in the form of a published and peer-reviewed scientific paper that details the use of relevant thicknesses of this material at various kVp values.