The radioprotection division of the Swiss Federal Office of Public Health has published some brief directives on how to build shieldings of nuclear medicine facilities, such as scanner rooms (PET-CT, SPECT-CT), application rooms, preparation labs, patient therapy rooms for in-patient radioiodine therapy, decay tanks and more. You can find the directives based of Swiss regulations here http://www.bag.admin.ch/themen/strahlung/02883/02885/02890/index.html?lang=de Unfortunately the documents are only in German, French or Italian. If you have any specific questions in mind I can try to give you some other references.

Hi,

The AAPM has published the 'PET & PET/CT Shielding Requirements'; which is the report from AAPM Task Group 108 (in Med Phys 2006 33:1). This report has a wealth of information regarding the calculations.

Andrew

Apart of the AAPM-TG108 for PET shielding calculations, I recommend the general document IAEA-Safety Reports nº40 "Applying Radiation Safety Standards in Nuclear Medicine"

The IAEA has a whole series of such documents on their website. Both for radiotherapy, radiology, conventional nuclear medicine and for a PET/CT centre. The IAEA safety report 40 is just one of a whole series. The layout of their website is in constant flux and not all documents can be found at any given time, unfortunately.

The AAPM =TG108 work is an excellent starting point for PET/CT shielding [no  one buys a dedicated PET-camera any more].

I have written software [python 2.6]  that can be used to calculate the net effect of  'distributed' shielding that may be used for a nuclear medicine department situated on a single floor. The code starts with a floor plan of the centre-lines of all walls and specifications of what sources and activities take place in which room how often, and for what time. Our physicist has done an independent validation of the code.  

In the past 8 years I have done the shielding designs of 1 PET/CT centre and 2 departments of nuclear medicine with PET/CT and with 131I-iodine treatment facilities. In september we will move into our new department.

In nuclear medicine there is often some room for a trade-off between physical and procedural safety measures. So such shielding calculations should be a team effort and the team should include an experienced nuclear physician. The routing and timing of injected patients must be taken into account.

Shielding is only part of the story. Each design should be very well documented in anticipation of future decommissioning or modification. Working with radio-isotopes implies taking responsibities for the long term very, very seriously..

A lot of the details depend on anticipated number of diagnostic procedures, equipment, local practices, local legislation and local customs. This is not strictly a scientific topic but a major engineering one. Simple answers do not suffice here.

One has to anticipate the patient numbers 10, 20 years from  now and have a good knowledge of the technology involved. For example the required doses in case of 18F-FDG have dropped considerably, but a further drop is not likely anymore.

You ask for far more details than this communication channel is suited for, so i limit myself to a few references that can all be found on line. There are far more on line.

Draft regulatory document RD-52 Design Guide for Nuclear Substance Laboratories and Nuclear Medicine Rooms  from Canadian Nuclear Safety Commission  Nov 2008 [or more recent final text]

Shielding of Medical Facilities. shielding design considerations for PET-CT facilities   Juan Cruzate & Adran Discacciatti

The Design of Diagnostic Medical Facilities where Ionising Radiation is used

A Code of Practice issued by the Raduiological Protection Institute of Ireland June 2009

PET/CT shielding design comparisons. Thesis by Audra Lee Coker  Texas A&M Univiersity  May 2007

Nuclear Medicine Resources Manual    IAEA 2006

Safety Report Series No. 58  Radiation Protection in Newer Medical Imaging Techniques: PET/CT  IAEA 2008

Safety Report Series No.  47  Radiation Protection in the Design of Radiotherapy Facilities  IAEA

Safety Report Series No.  40  Applying Radiation Safety Standards in Nuclear Medicine  IAEA

Safety Guide No. RS-G-1.10 Safety of Radiation Generators and Sealed Radioactive Sources.  IAEA 2006

IAEA Human Health series no. 11  Planning a Clinical PET Centre   IAEA 2010

[in this same series several other publications are also of interest,  I suggest you look for those as well]

Dear all researchers

thanks a lot for your excellent answers

When designing nuclear medicine buildkings, a number of considerations must be taken into accountm that so far have not been published:

If your department performes radionuclide therapy, including 131I-radio-iodine, and your legal system demands of you that you isolate patients for some time, the sewage system of the hospital needs to be checked as wel:

-1- the trajectory of the piping of the sewage water drainage system is such that no radiation burden is caused to patients, personel, public

-2- the trajectory must be such that any radio-iodine in sewage wat can not affect other equipment. Practical: the pipes should NOT pass underneath a camera room

-3- If waste water treatment or temporary storage is required, an extensive safety analysis is required. In The Netherlands several potentially serious incidents have occurred with such temporary storage facilities, intended for the decay of waste water containing radioiodine. In Germany a different type of installation is required, with dissimilar weak points. Waste water after radio-iodine treatment must be taken serously. In our hospital we have reached amounts in excess of 15 GBq and concentrations of 50 MBq/l.

-4- In The Netherlands several contemporary hospital designs included a waste water processing plant. [I know of at least 4 such hospitals]. These are based on a common design objective: getting all drugs and iodinated contrast agents out of the waste water. However, the sewage water from a department of nuclear medicine should NOT be allowed to be processed with such a system, else that processing plant becomes quite radioactive and a health hazard for the staff involved.

-5- When sewage water containing radioiodine is produced, an extensive analysis must be made of possible incidents and disasters, as some can cause the uncontrolled release of radioiodine.  I give one example here, but l know of dozens more. In many hospital the tanks for the decay of radioiodine contaning waste water are situated in the basement. In one such hospital, other basements were flooded occasionally. If a tank is only partially filled and the basement is flooded during a period of heavy rain, the tank might float. This may cause the piping to break, resulting in an uncontrolled release and in a totall loss of the pumps and electric installation of that basement. I know of at least one hospital where a 10 m^3 tank [30 y old] suddenly burst open, releasing all its contents in a moment. So accidents DO HAPPEN.

A good design of nuclear medicine buildings helps mitigate even such disasters. In the building stage a cubic meter of concrete is almost free, whereas retrofitting safety-related measures afterwards is at least 100 times more expensive.

It is absolutely and unquestionably necessary, that the building lay-out and shielding is designed by a physicist in cooperation with an experienced nuclear physician. An architect / construction engineer has a simple role here: implement what is specified and do not attempt to improve on such design.

Another strong word of advice: when building for nuclear medicine: 100% on-site inspections of drawings and of work any time all the time!!!  This is the most cost effective approach for builders and hospital owners alike. Any corrections needed later during design and construction comes with added cost. No construction company can convincingly claim "experience".

When building for nuclear medicine, the only way to save serious money is with good forethought and a multidisciplinary design-team. Taking short-cuts at this stage and building without allowing access for frequent continuous on-site inspection are sure recipes for financial disaster. Unfortunately this is not stresses nearly enough even in the otherwise excellent publications of the IAEA.

To Nur Hafizah Mohad Azmi: If your country does not yet have "mature" legislation regarding nuclear medicine and safety, do use the IAEA documentation extensively. The IAEA even has a large PDF-file on line named "Handbook on Nuclear Law". It is on www.iaea.org, but its location has changed several times over the past few years, so i do not give a full URL.  Most legislation in most modern countries is to a considerable extent synchronised with the IAEA documentation. If you have to discuss matters with authorities and no clear local laws apply, showing them that you follow IAEA recommendations and guidelines is likely to be helpfull.

It´s no problem, IAEA report 1160.