CT scanners

Description

CONTRACT-ACJJ-EN3IN0. Great Ormond Street Hospital for Children NHS Foundation Trust wishes to purchase a microCT machine for continued development of our minimally invasive autopsy and post-mortem imaging research programme. Expansion of PM imaging to adequate. lt image small gestation foetuses and foetal / embryonal organs at high resolution at GOSH is essential to permit development of this service for potential widespread clinical application. A particular focus of the microCT machine will foetal imaging including very high resolution imaging of small foetuses and foetal organs and imaging of mid-late gestation foetuses. Purchase of the microCT scanner will potentially enable us to significantly expand the applicability of this approach. Our research programme, with regards to PM imaging and less invasive autopsy, is carried out in partnership with both the UCL Institute of Child Health (ICH) and imaging at UCL. This particular project requires both particular features of the microCT scanner itself in order to adequately meet the specimen needs, and also requires easy integration with data generated by colleagues in other UCL departments such as engineering and physics, which will dramatically minimise the lead time for assessment of methods to clinical applications. Furthermore, the machine should produce data in formats for which our existing work-flows are optimised. To this end we propose to purchase a Nikon XTH225ST system which offers us the following features that are essential for our work: 1. A very large sample capacity, up to 600mm high and 50kg. This would suit our range of specimens, which could potentially include whole placentas (approximately 25-30cm) and large paediatric tumours (20cm +) which could be examined without the need to pre-dissect the specimen. 2. A large working volume and field of view, this would allow us to scan samples up to 300mm in diameter in a single scan without the time penalty of panel scan. Detector area shall be at least 400mm x 400mm (no panel scan). Focus to image distance needs to be selectable from 600mm to 1 080mm to allow optimisation of scan time and field of view for very wide specimens from very small to very large. 3. The high power magnetically focussed 30kV to 225kV, 225W X-ray source enables very fast scan times without loss of resolution. This is very important because biological specimens slump/dehydrate quickly so increasing the current enables us to cut the imaging times significantly and leads to a large reduction in failed scans. The high power of this source also provides us with the ability to use 150kV plus if needed to adequately image dense and complex specimens e.g. placentas, tumours and virtual autopsy as well as implanted devices and prosthetics. 4. If required in future the system can be upgraded with a 450W continuously cooled rotating target. This would allow us to scan samples 3 times faster while maintaining the voxel resolution of a static target and would greatly increase our work throughput. 5. User selectable Multi-Metal target allows different target materials (Tungsten, Molybdenum, Copper or Silver) to be chosen quickly without breaking vacuum or needing to re-boot so that it can be changed at will between scans. This is extremely important for soft tissue/biological work where we are continuing to investigate optimisation of imaging protocols. The wide range of pathologies that we are investigating means easy availability of different X-ray spectra is essential to optimise imaging different medical contexts. 6. The detector must have a transparent input window (e.g. carbon fibre) and good spectral response to low energy X-ray (to <20keV). This will provide us with the ability to take low energy scans of histology blocks down to 20kV using the choice of Silver, Copper or Molybdenum target materials. The detector for this system must also offer extremely high overall sensitivity up to the maximum X-ray energy, 65 536 grey levels and better than 88dB dynamic range (defined as: 20 × log [(65536 — Offset) / RMS-Noise]). 7. Proven image quality across a wide span of pre-natal, neonatal and paediatric pathology applications. 8. Immediate delivery. Expert local technical and service support must be available outside normal working hours — minimum 8:00 to 20:00, 364 days per year.