## 4 Mobile Head CT Scanner and Rotorcraft Retrofitting
### Design Considerations for Retrofitting Head CT Scanners into Rotorcraft
#### 4.2.2 Weight and Size of the Mobile Head CT Scanner  
With the major components identified and determined for modification, removal, or keeping (Table 2), the CT scanner can then proceed to be modified accordingly. As CereTom is 13 cm taller than the cabin height of an AW189, lower compartment, fender, and caster wheels were proposed to be removed from the main structure of the CT scanner. Therefore, a new support structure is needed to attach the gantry of the CT scanner to the helicopter floor.  
The weight and geometry of the CT scanner are the two most important factors to consider when designing a suitable support structure to attach the CT scanner onto the helicopter floor. Firstly, the support structure should demonstrate sufficient strength to resist both the static weight of the CT scanner gantry and the components concealed within and the vibrations induced from both the rotation of the CT scanner during operation and the helicopter floorboard during flight and landing. Therefore, it is ideal to select the lightest mobile head CT scanner model where possible as it simplifies the design process by lowering the amount of weight reduction required, and the proposed support structure will have a lighter weight and smaller size as it has a lower load-bearing requirement. For the geometry of the CT scanner gantry, it is ideal to design a support structure that can attach to it while keeping the overall dimensions of the CT scanner as small as possible to allow for more working space for the onboard staff within the small enclosure of the aircraft interior.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**CT Scanner Components** & **Role** & **Keep/Remove/Modify** & **Justification** \\ \hline X-ray tube & Emits X-ray, which goes through the patient’s head and is received by the detectors. & Keep & Primary functional component of CT scanner. \\  & Receives the X-ray emitted from the X-ray tube, which will be used to process X-ray images. & Keep & Primary functional component of CT scanner. \\  & A rotating support where both the X-ray tube and detector are attached diametrically opposite. & Keep & Limited modifiability as it may severely affect the function of the CT scanner. \\  & & & The size and correspondingly weight can be further reduced to fit into nominated aircraft, \\  & Support frame & Supports the structural weight of the CT scanner. & Modify & Limited modifiability as it may severely affect the function of the CT scanner. \\  & & & The size and correspondingly weight can be further reduced to fit into nominated aircraft, \\  & & & however not compromising on structural integrity. \\  & & & Will be modified according to the shape of the support frame. \\  & & Aids hospital staff in & Not required as the CT scanner \\ Caster wheel & maneuvering the CT scanner with ease. & Remove & will not be mobile once attached to the aircraft interior. \\ Battery & Power source for the CT scanner. & Keep & Must be retained to serve as backup power source for the CT scanner. \\  & & & scanner. \\ Processor & & & Primary functional component of CT scanner. \\  & & detectors into a greyscale image. & Keep & No longer used as the driving mechanism for the CT scanner. \\  & & Drives the movement for the entire CT scanner. & Remove & Carepillar tracks are no longer in use. \\  & & & in use. \\ \hline \hline \end{tabular}
\end{table}
Table 2: CT scanner components and descriptions.