Radiopharma technology

MITIE Science Projects, the specialist cleanroom, laboratory and controlled environment division of MITIE Engineering Services, has firmly established itself as a contractor in the rapidly emerging radiopharmaceuticals market, which is actively involved in a number of Positron Emission Tomography (PET) facilities. Although there is only a handful of PET scanners operating in the UK, the technology has been widely adopted throughout the USA (more than 160 sites) and Continental Europe (more than 120 sites) and will be seen increasingly in the UK in regional facilities and in the larger hospitals. To date, PET in the UK has been severely restricted by the lack of availability of scanners and the production facilities for radionuclide tracers, but this is an issue that is now being addressed. Bill Bordill, director of MITIE Science Projects Northern Division, commented: "In January 2003, the Intercollegiate Standing Committee on Nuclear Medicine called for the development of a national policy on the establishment of PET facilities in the UK. This included the recommendation that at least 15 PET camera facilities should be established in the UK over the next 3-5 years, and that 40-60 sites should be set up over the next 10 years. This is clearly an exciting niche market which MITIE Science Projects is ideally placed to serve." The specialist skills available within the team, through the amalgamation of experienced cleanrooms, controlled environments and building services teams, enable highly sensitive environments to be developed to the highest specifications. The team has built one such facility and is currently involved with another, both of which stretch conventional pharmaceutical cleanroom design and must incorporate cGMP, MHRA and Nuclear Radiation guidelines. The radiopharma market requires the construction and fit-out of bespoke facilities to accommodate the new PET imaging technology. This relies on the injection of a harmless radioactive tracer, such as FluoroDeoxyGlucose (FDG), to investigate changes in metabolic processes in the body. These potentially are caused by the onset of disease and can be detected with this technology before the onset of the physical changes that can be visualised by scanning techniques such as MRI or cross-sectional imaging. For instance, malignant cells have a greater uptake of glucose and this can be detected by FDG-based PET imaging.

Tight timescales PET tracers are manufactured in a cyclotron that accelerates sub-atomic particles that bombard the tracer material to make the radionuclide. These isotopes have very short half-lives so they have to be used within two and a half hours of being manufactured. Tight timescales mean that the production facility must either have its own treatment/test facility or be close to an external treatment centre. The likelihood is that these facilities will be located throughout the UK to provide the nationwide coverage that the NHS, private health clinics and pharmaceutical companies will demand. The short shelf life (half-life), which can be as little as two minutes for some products, means that the facility must be able to accommodate FDG production, delivery, PET imaging and pre/post-delivery patient care. This represents a unique and interesting challenge for the designer who must consider the regulations protecting the facility, people, waste and product. A Prior Risk Assessment and specific reference to Ionising Radiation Regulations, Radiation (emergency preparedness) Regulations, Environment Agency, LA Planning Authority, CDM Regulations, Building Regulations cGMP and the MHRA is currently required. A construction feature typically required for these RadioPharma facilities would be Safe Change Filter Housings, whereby the filter medium remains permanently enclosed, even when being changed. This is a requirement to ensure operator safety. The Cyclotron and Hot Cells are very sensitive and extremely expensive capital cost items, which require extensive planning and co-ordination to be successfully incorporated into the facility. Essentially these require cleanrooms with added features to capture radioactive gases i.e. charcoal safe change filter units where the charcoal is used to absorb the contaminated particulate and progressively reduce the radiation as the air passes through the filter. Bordill adds: "In one facility in Scotland the requirement was for containment to be ISO Class 2. This was achieved by a negative 'synch' pressure cascade with turbulent air flow and low level return. It also utilised pass through hatches with mechanical interlocks, interlocked doors and multiple change room air locks."