The core of CT's differentiated competition

From a hardware perspective, a CT scan is composed of five major parts: the frame, the scanning bed, the tube, the high-pressure generator, and the detector. But for the frame, users only care about the aperture and rotational speed. For scanning beds, users are simply indifferent because they are certain that "it won't affect the overall situation". Therefore, whether from the perspective of the user or the central component, the important parts of CT are always the tube, the high-pressure generator and the detector. CT tube

For a long time, both users and CT manufacturers have regarded the width of the detector as an important basis for evaluating the level of CT. For instance, a 2cm detector is an entry-level CT, a 4cm detector is a mid-range CT, an 8cm detector is a high-end CT, and a 16cm detector is an ultra-high-end CT. However, in fact, we have all overlooked a very important point: medical institutions purchase CT based on budget, and they often deal with CT of the same level, such as 16-slice CT, 64-slice (80-slice)CT, 128-slice CT, 256-slice CT, etc. At this point, for hospitals, all CT detectors are the same because for CT of the same level, the user experience of their detectors is really no different.

Similarly, the high-voltage generators configured for CTS of the same level are almost all the same. For instance, a 64-slice CT is equipped with a 60kW or 80kW high-voltage generator, while a 128-slice or higher CT is equipped with a 100kW high-voltage generator. Although the response speed, stability and control accuracy also determine the quality of the high-voltage generator, due to the excessive maturity of the high-voltage generator, users cannot feel the difference at all.

Therefore, whether from the perspective of user application or hospital procurement, the focus of CT is often on CT tubes. This is why hospitals always discuss the tubes separately every time.

Perhaps you may ask, aren't the tube configurations for CT at the same level also about the same? For instance, a 16-speed CT is equipped with a 5.3MHU or smaller tube. CT with 64 rows or more is equipped with 8MHU or more tubes.

This is indeed the case in terms of performance, but the actual situation is clearly not!

Firstly, the tube configurations of CT machines from different brands vary significantly. For instance, 16-row CT machines (including 32-row and 40-row ones) are equipped with tubes of 2MHU, 3.5MHU, 5.3MHU, and even 8MHU. For CT, "stacking materials" with tubes is very sincere and can also deeply touch users, because everyone knows that the larger the heat capacity of the tubes, the better.

Secondly, the performance of different types of tubes varies significantly. From the perspective of equivalent heat capacity, 5MHU and 30MHU are not the same thing. From the perspective of exposure seconds, 200,000 seconds and 2 million seconds are not the same thing. From the perspective of bearing technology, liquid metal bearings and metal ball shafts are not the same thing.

Therefore, it is reasonable for hospitals to pay too much attention to CT tubes, to the extent that the starting point of a good CT is the tube. Without a good tube, there can be no good CT.

2. What is a good CT tube?

By the end of 2022, the global CT inventory exceeded 450,000 units, mainly distributed in the Americas, Europe and the Asia-Pacific region. Among them, China's CT inventory was nearly 55,000 units, accounting for approximately 12% of the global total, still lagging far behind the 40% of the United States.

If the inventory is insufficient, the utilization rate will make up for it. Unlike in Europe and America where the tubes of each CT machine are replaced every 2 to 4 years, due to the huge patient flow in China, it is common for a single CT machine to examine 200 to 300 people per day, which leads to the replacement of the tubes of each CT machine every 1 to 2 years.

Obviously, in our country, CT requires better tubes. Only powerful tubes can support high-throughput examinations and handle the urgent problems on the clinical front line. After all, the quality of CT directly affects its operating speed, imaging effect and service life. So, what exactly makes a good CT tube?

We believe that from the perspectives of clinical value and hospital management, a good CT tube should meet three "satisfications" :

Meet the demands of higher-throughput inspection

In the face of such a large number of CT examinations in our country, to reduce the waiting time for patients, it is necessary to improve the heat dissipation efficiency of the tubes, that is, to increase their equivalent heat capacity. That is, high-throughput examination = large heat capacity tubes. Especially for medium and high-end CT that needs to be used for applications such as whole-body vascular, multi-site combined scanning, and energy spectrum imaging, large heat capacity tubes are even more required.

The emergence of technologies such as liquid metal bearings and direct anode cooling has significantly increased the equivalent heat capacity of the tubes, raising it from the previous 8MHU to 30MHU today, making it easy to handle the challenges of high-throughput patients. At present, the heat capacity tube in the industry was invented by Dunlee and once reached an astonishing 34MHU.

Take the 64-speed CT as an example. In the past, it was usually equipped with 6.3MHU and 7MHU tubes, but now there are 19MHU Dunlee CT3000 and 25MHU Dunlee CT4000. It has become an inevitable trend for mid-range CTS to be equipped with super large heat capacity tubes.

Based on Dunlee's stress test, we can understand exactly how much the CT scan volume of the ball tube equipped with liquid metal bearings can be improved: 1) Compared with the Dunlee CTR2150 ball tube using traditional ball bearings, the scan throughput of the Dunlee CT3000 using liquid metal bearings is 38% higher; 2) Compared with the Dunlee CTR2280 ball tube using traditional ball bearings, the scanning flux of the Dunlee CT4000 using liquid metal bearings is 78% higher.

Perhaps you say this might be caused by insufficient CTR2150 and CTR2280. Of course not. Take CTR2150 as an example. This is a classic 5.3MHU ball bearing tube and also an object that is highly sought after for simulation. It can be regarded as the "pioneer" of domestic 5.3MHU ball tubes.

Meet the demand for a longer service life

Regardless of the level of CT, the fundamental demands of medical institutions for CT are diverse, namely: high performance, high stability, high-definition images, high-throughput examination, and low maintenance costs. One of these is jointly determined by components and services.

Take a 64-slice CT with a unit price of about 5 million yuan as an example. Its warranty fee is usually 600,000 to 800,000 yuan per year. If the tube is good enough (replaced every 3 to 5 years instead of every 1 to 2 years), and the hospital has the ability to maintain it, then at least 10 million yuan can be saved for the hospital in 15 years, which is equivalent to two CTS. Although other components may also break down, compared with the ball tube, the cost of both money and time is much lower.

Therefore, we can say that it is very important to choose CT tubes with long quality and service life, which can reduce the maintenance cost and downtime of the equipment and minimize the impact on the overall operating cost of the hospital. That is, short-life tubes = low operating cost.

However, manufacturing short-lived tubes is a challenge, which not only requires new tube technologies such as metal ceramic tubes, liquid metal bearings, AEG anode grounding, and direct anode cooling; More importantly, the consistent tube manufacturing process. The difference between three years of manufacturing experience and thirty years of manufacturing experience is obvious.

Meet the demand for a better user experience

Good user experience = good image quality + good patient experience.

From the perspective of image quality, the quality of CT images is influenced by multiple factors. Apart from human factors, the overall performance of the equipment often plays a decisive role, especially for the ball tubes.

For instance, grounding the anode of a tube can capture stray electrons, reduce unnecessary radiation and improve image quality. For instance, the flying focus technology can increase the sampling rate without increasing the X-ray conditions, thereby significantly improving the clarity of the image. Therefore, a good ball tube should incorporate these new technologies.

From the perspective of patient experience, on the one hand, there is a need to reduce the anxiety and radiation dose of patients during CT examinations, especially for children and the elderly. More importantly, it is necessary to eliminate the scanning interruption caused by all kinds of reasons. In this regard, the tube is also very important.

For instance, compared with mechanical ball bearings and tubes, liquid metal ball bearings and tubes generate almost no noise or vibration during operation, which helps to increase patient compliance and improve scan quality. For instance, low-dose scanning with low kV and high mA is not easy. Due to the 15% rule, high-power tubes are required to complete it. Therefore, good golf clubs should also incorporate these new technologies.