Tokyo Women’s Medical University Yachiyo Medical Center was established in 2006 with the aim of achieving a good balance between warmhearted patient care and high-level acute medical services, functioning as a core hospital valued and trusted by the local community. With the addition of a new 501-bed hospital ward and a heliport, the medical center achieved Joint Commission International accreditation in 2020.
Our center has two fluoroscopic examination rooms, one of them is a multipurpose room and the other is a specialized room for endoscopy procedures. When the time came to replace the fluoroscopy system in the multipurpose examination room, we decided to install a Zexira i9 digital X-ray radiography system in August 2021.

In addition to general gastrointestinal angiography, we perform a wide range of diagnostic and therapeutic fluoroscopic procedures, including fistulography in the fields of gastroenterology and surgery, myelography and nerve root blocks in the field of orthopedics, bowel repositioning and voiding cystourethrography (VCUG) in the fields of pediatrics and pediatric surgery, and ureteral catheterization in the field of urology. These procedures are often performed with ultrasound and/or endoscopy used in combination.¹

During fluoroscopy procedures, depending on the specific objective, we use the “inch-up” function to move the FOV, allowing us to precisely track the movements of the catheters and guidewires. In a conventional fluoroscopy system, the FOV is moved by physically repositioning the imaging system in the longitudinal direction and the patient table in the lateral direction (figure 3). When the inch-up function is used in such a system, the radiographic image is displayed by magnifying the central area of FPD. In Zexira i9, although the method is basically the same in principle, the difference is that the inch-up function allows the FOV to be moved anywhere within the fully open field size of the FPD (43 cm × 43 cm), eliminating the need to reposition the imaging system or the patient table (figure 4). For this reason, the conventional limitation of “the center of the FPD” no longer applies to the magnified area displayed as an inch-up image.

In fluoroscopic examinations or therapeutic procedures (and especially in invasive procedures), the operator is instructed to always watch the surgeon‘s hands and to notify the surgeon before moving the field of view or to ask the surgeon to temporarily move their hands away. A common, but very dangerous, concern is that inexperienced operators tend to rush to move the FOV in order to track the target while looking only at the fluoroscopy monitor.
When i-fluoro is used, because there is no need to physically reposition the system, the FOV can be moved safely without interrupting the surgeon‘s work. In addition, during invasive procedures, patients are unable to see what is happening, so they tend to focus on what they hear and feel.² With i-fluoro, patient anxiety is reduced because there is no disturbing sound or vibration due to mechanical movement of the system. Nevertheless, even when i-fluoro is used, it is essential for the operator to always observe the surgeon‘s hands and pay close attention to ensure safety.

This section describes retrograde cystography (RCG) in detail as an example of the clinical application of i-fluoro.
(1) Place the patient on the table. Turn on the X-ray field indication lamp. Position the imaging system and the tabletop at a position where the target is included in the FOV and set the position in advance (figure 6a).
(2) Perform fluoroscopy for a short time to obtain a last image hold (LIH).
(3) Activate i-fluoro. Select the field size to be used for examination. Set the position precisely based on the LIH without additional fluoroscopy (figure 6b). Start the contrast enhancement procedure (figure 6c).
(4) During the procedure, adjust the field size or move the FOV as required.

Figure 8 shows two images of the same patient: a lateral view of the lumbar spine obtained by general radiography (figure 8a) and a contrast-enhanced image of the spinal canal obtained by Zexira i9 (figure 8b). Although the exposure dose is much lower for the image in figure 8b, low-contrast regions near bone are clearly visualized and excellent contrast enhancement is seen in the spinal canal, which was the primary diagnostic objective of this study. By introducing the FPD and , resolution in low-contrast areas is markedly improved even at lower doses. In addition, processing can be performed with different parameters to optimize image quality in both low-absorption areas and high-absorption areas, providing extremely clear images with outstanding gradation which was previously very difficult to achieve in a single image. Various functions are also provided to reduce radiation exposure. For angiography, a retrospective fluoroscopic storage function has been added, which is now a common feature for use in combination with radiography. Image brightness was previously controlled using a function known as “automatic brightness control” (ABC), in which the brightness is controlled by reducing or increasing X-ray output, but it is now controlled by digitally adjusting the brightness using a new function known as “digital brightness adjustment” without the need to change the fluoroscopy dose rate. In addition, three fluoroscopy dose modes are available, allowing the fluoroscopy dose rate and digital brightness correction to be adjusted with no loss of image brightness. The grid-controlled X-ray tube supports pulsed fluoroscopy with a short wave head and tail at nine selectable frame rates: 1, 2, 3, 5, 7.5, 10, 15, 20, and 30 fps. These features allow us to strategically employ the most suitable frame rates. For example, 15 fps can be selected for clearer visualization of movement, 3 fps can be selected for VCUG in pediatric patients, and so on.

References
1. Yuko Kobashi. Points to be noted when performing examination (Fluoroscopy): Clinical Image, 36(14):30-37, 2020. (in Japanese)
2. Japanese Association for Operative Medicine: Practice Guidelines for Surgical Medicine (revised edition). 2013. (in Japanese)



The contents of this report include the personal opinions of the author based on his clinical experience and knowledge.

This article is a translation of the INNERVISION magazine, Vol.36, No.12, 2021.