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From Concept to Clinical Practice - Following the Technical Evolution of Angio CT

June 23rd, 2023

Angio CT was born from an idea first conceived 30 years ago by Dr. Yasuaki Arai, former director National Cancer Center, Tokyo, Japan. Over the years, its initial technical evolution has been driven by Canon Medical expertise. Mr. Atsushi Gotoh, Former Angio CT team leader at Canon Medical, describes the key features of the system and milestones in the early development period.
Angiography system in 1992.
1992 - The birth of an innovation driven by patient needs
The idea for Angio CT originated from the desire to improve imaging and interventional procedures for patients.

I joined the Angio CT story in (1994) as a member of the development team. Work to create the system had already begun in 1992. One of our starting points was an Angiography system, like illustrated here (Figure 2).
Figure 2.
Let me explain the mechanism of this 1992 system. This is a CT-based system. The first generation utilized a CT-based table instead of a catheter table. The X-ray tube is not visible, because it is inside the CT table. Above there is a large detector called an "I.I.", (Imaging Intensifier) that comprises of a vacuum tube and an X-ray enhance electron. It is amplified, and provides an output image on the fluorescent screen which is suspended from the ceiling. It uses a vacuum tube and is equivalent to the FPD in current systems. At the time, CT systems were floor-mounted and not movable.Threedimensional C-arm rotation was not possible then.

Dr. Arai (Figure 3) first came up with the Angio CT hybrid idea. This was during the period when he was working at Aichi Cancer Center in Japan. His main focus was to avoid transferring the patient form the CT to the Angio room and vice versa. Dr. Arai has always emphasized the importance of not moving patients in between examination rooms. Moving the patient takes a lot of effort and requires support from a number of hospital staff. For example, there are X-ray tubes, ECG electrodes, other cables, and tubes involved in Angiography systems. If these have to be disconnected to move the patient, it places a great burden on them, as well as the staff members involved. It is also time consuming. Therefore, it is important that all the procedures can be performed while sharing one table between Angiography and CT scan. CT is used to examine the lesion in advance. While the Angiography C- arm is mostly used to confirm the results of the examination, and to evaluate results before and after the examination.

The need to perform Angiography and CT using the same patient table within a single room led to the concept for the world's first Angio CT system. At the time, the initial development was mainly handled by the CT team rather than the VL team.

1994 - Introduction of the C-arm
In this year the C-arm was first introduced in the Angiography system. This C-arm was an ancestor of the Alphenix. Originally, the arm was suspended from the ceiling. This not only allowed scanning of the patient from the front, but also made it possible to perform scanning from various angulations.

However, the CT was still fixed to the floor, requiring a specially designed patient table. This was the reason for a very long tabletop. Unlike current Angio CT systems in which the CT system can move over rails, a CT system fixed to the floor was used in combination with a long tabletop like the one shown in Figure 4 (1996). However, the maximum range how far the tabletop could be extended was limiting the desired patient coverage for CT scanning. Here it is illustrated how the system looked during the period of technological transition.
Figure 3: Dr. Arai
Figure 3: Dr. Arai
Figure 4: The Angio CT system installed in 1994.
figure 5: The Angio CT system produced in 1996. The CT gantry is now movable on the floor rail. The basic design of the well-known Angio CT system was invented at this time.
1996 - First movable CT
We identified that there was a problem in the movement range for the C-arm, and so decided to rotate the ceiling rail layout perpendicular to the catheterization table.

In 1996, we tackled this technical challenge and were able to develop the first movable CT.

The ceiling travel rails are not visible in figure 5 of a system from 1996, the duct hoses are mounted on the ceiling, the system began to resemble the current Alphenix C-arm. Ingenuity was required to create this feature. The layout of this C-arm was designed very carefully. Generally, for the C-arm for Angiography systems, if it is used as a general vascular system, two rails are installed in the longitudinal direction, so that the C-arm can be moved in the patient head/foot direction.

The movement range was wider in the longitudinal direction. As the C-arm suspended from the rails, if it is moved along the rails, it cannot be retracted sufficiently if used as is in combination with the CT system.

To address this problem, the layout was adapted and the direction of the C-arm is perpendicular to the catheter table. This ensured a longer movement range in the lateral direction than the longitudinal direction.
The CT base can move on the floor to realize the helical scan. This unique concept was born by Toshiba/Canon in 1996.
Figure 7: The ceiling C-arm can park perpendicular to the table and CT gantry. This unique design doesn’t disturb patient approach from both right and left side of the patient.
In this way, the C-arm can be completely retracted beyond the movement range of the CT gantry. (Figure 7). With this layout design, it was intended that both the Angiography system and the CT system could respectively fulfill their maximum capabilities when used individually. A great deal of thought went into development of the system, with the focus from the very beginning on finding solutions to the multiple challenges. This layout design has basically been maintained up to the present.

This required the most effort. And this was all possible thanks to input from many physicians.

As the Angio CT system was first developed in Japan, where examination rooms are generally small, we considered various ways to design a compact layout that would provide an optimal fit.

Mass production started with the 1996 version of the system.
The Flat Panel Detector was adopted for C-arm in 2003.
After we started mass production, the system was installed at many sites. This seems to have been a key year. For the launch of the "3-axis movement C-arm with 3D Angio".

As shown in Figure 7, a common table designed for a helical CT system was first installed at National Cancer Center, Japan in 1996. A multi-angle-approach C-arm and a ceiling-suspended C-arm were installed at NCC Hospital East. Rotational DSA and an Angio CT monitor were also installed.

Angiorex was the original name for the Canon Medical Infinix back then. The present concept was already established by this time, including its structure, movement, and layout.

Launch of the Infinix and Alphenix
The VL BU released the Infinix series, with the name changed from Angiorex. This is now known as Alphenix.

Although it's been 20 years since then, we have provided updates to the CT- and Angiography systems as we continued the development continiously. Progress through this kind of steady effort has achieved a great deal.
Canon’s latest Alphenix 4D CT in 2022. Combination of the Alphenix Sky+ arm and the Aquion ONE / GENESIS edition.
Now, after many changes and improvements, the Alphenix 4D CT has achieved the stage where the features allow users to deliver safer and effective procedures with Hi-Def Angio, ONE-beat Cardiac, Dynamic 4D Brain, Whole Organ Perfusion, Spectral CT and more. All of this under dose management and deep learning reconstruction for efficient imaging and less dose.

The Aquilion ONE combination of the Alphenix 4D CT now provides a full 50 cm scan FOV with up to 16cm of wide Z-coverage, and patient specific mA modulation. Also the recent technology permits to harness the power of deep learning reconstruction that delivers excellent energy separation for spectral analysis with high resolution. These reconstructed spectral images are then delivered directly to your reading station for immediate ans analysis.

This is all possible thanks to Vitrea, our interactive multi-modality workstation, that analyzes the image data including quantification of perfusion data for more confident diagnosis with the wide range of applications.

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