CN114984462B - A Cherenkov light dose monitoring method and device based on multi-channel imaging - Google Patents

Abstract

The invention provides a cerenkov light dose monitoring method and device based on multichannel imaging. Wherein the device includes: a multi-channel camera beam splitter assembly that splits the cerenkov light, the beam splitter assembly consisting of an RGB dichroic beam splitter and a bandpass filter, allows cerenkov light signals incident from the zoom lens to be redirected to the appropriate camera channel according to wavelength. And three independent ibcd modules packaged in a three-tube color camera assembly, the red, green, and blue channels being equipped with red, green, and blue sensitive ibcd modules, respectively. The camera is remotely triggered by stray X-rays, synchronized with the linac pulses and gated. The multi-channel processed image is finally combined into an RGB color image. The invention has the characteristics of visual imaging, large image information quantity, high positioning precision and the like, and can effectively improve the dose monitoring effect in radiotherapy.

Description

A Cherenkov light dose monitoring method and device based on multi-channel imaging

Technical field

The invention relates to the fields of radiotherapy and radiation imaging, and in particular to a Cherenkov light dose monitoring method and device based on multi-channel imaging.

Background technique

Cancer has become the number one killer that threatens human life and health. As one of the main means of treating malignant tumors, radiotherapy plays an increasingly prominent role and position in tumor treatment. Photon therapy is currently the most mature radiotherapy technology. However, due to the mechanical characteristics of radiotherapy equipment, the execution process of the treatment plan, and changes in beam parameters, the treatment beam will inevitably produce dose deposition on the organs at risk surrounding the target area, affecting radiotherapy. Effect. Therefore, new real-time dose detection systems are in urgent need of further development.

Cherenkov radiation is a phenomenon of super-light motion of charged particles in a medium. When the speed of high-speed charged particles in the medium is greater than the speed of light in the medium, local polarization is generated in the direction of the motion path, and in Visible light and near-infrared photons are released during the return to equilibrium state. Robertson et al. applied Cherenkov radiation to the field of biomedical imaging for the first time and proposed the concept of Cherenkov photoluminescence imaging. Cherenkov photoluminescence imaging has the characteristics of non-invasive, repeatable, and real-time imaging, and can especially be used to monitor the dose in tissues during radiotherapy.

Currently, Cherenkov light imaging dosimetry systems mainly use monochromatic intensified cameras. Due to the red and near-infrared weighted emission of tissues, in vivo Cherenkov light imaging in other bands has received almost no attention. However, changes in blood content and oxygenation within tissues have a large impact on light emission, and the associated spectral changes are thought to be diagnostically helpful. Although Cherenkov imaging systems have been around for many years, the advantages of multiwavelength imaging in the context of radiotherapy have not been explored in depth. Therefore, developing a Cherenkov light dose detection method and device based on multi-channel imaging is a key technical issue that needs to be solved urgently.

Contents of the invention

In order to solve the above technical problems, the purpose of the present invention is to provide a Cherenkov light dose monitoring method and device based on multi-channel imaging, which has the characteristics of intuitive imaging and high positioning accuracy.

In order to achieve the above objects, the technical solution adopted by the present invention is:

A Cherenkov light dose monitoring device based on multi-channel imaging, characterized in that it includes: a multi-channel camera beam splitter component that splits Cerenkov light, and the beam splitter component is composed of an RGB dichroic beam splitter ( 2) and a bandpass filter that allows the incident Cherenkov light signal from the zoom lens (1) to be redirected to the appropriate camera channel based on wavelength, and three independent iCCDs packaged in a three-tube color camera assembly Module, the red, green, and blue channels are equipped with red, green, and blue sensitive iCCD modules respectively. The three-channel images are spatially registered and then the three-channel images are fused to obtain the color Cherenkov light image.

The lens in question is a 10-100mm f/1.6 zoom lens (1).

The beam splitting device includes two dichroic beam splitters (2), which respectively separate the blue band and the red band, the blue band and the red band and the filtered green band from the Cherenkov light signal. are transmitted to the iCCD module respectively through a band-pass filter.

The iCCD module is composed of red, green, and blue sensitive enhancers (3, 4, 5) and a CCD module (6).

The image synthesis is to generate an RGB color image through image registration and color correction of multiple grayscale images obtained from multiple channels.

A Cherenkov light dose monitoring method based on multi-channel imaging, including the following steps:

A multi-channel camera was mounted on a tripod in the treatment room to acquire images, which were acquired in 16-bit raw format using C-Dose research software. Temporal and spatial median filtering is performed using 5 frames and 5 × 5 pixel motion windows on each camera's FPGA, eliminating additional denoising or smoothing in post-processing;

Collect a stack of 120 frames of darkfield images and calculate the average number of darkfield frames. For a given acquired data set, the frames are averaged for each of the three image stacks, and each averaged darkfield frame is subtracted;

Using checkerboard-based geometric correction, perform a two-dimensional polynomial transformation on the green, red, and blue images to spatially align the three channels to obtain a three-channel image;

By combining the RGB three-color channels, a colored Cherenkov light image can be obtained.

The beneficial effects of the present invention include:

(1) In the images obtained through multi-channel camera imaging in the present invention, various tissue features not only show different intensities, but also have unique spectral characteristics;

(2) The sensitivity of the images obtained through multi-channel camera imaging in the present invention to body surface features helps to more accurately track the daily posture of the patient, and the acquisition of biological information, such as blood volume and oxygenation saturation, can help Clinicians understand the patient's physiological response to treatment, such as the development of erythema;

(3) The technology of the present invention presents the natural superposition of Cherenkov light and background signals through simultaneous collection and accumulation, allowing for a more realistic visualization of the interaction between radiation and tissue;

(4) The present invention can obtain useful images without background subtraction because the contrast between the Cherenkov signal and the background is achieved through color perception.

Description of the drawings

Figure 1 is a schematic diagram of the multi-channel camera proposed by the present invention.

Figure 2 is a flow chart of the multi-channel imaging method proposed by the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the examples.

As shown in Figure 1: A Cherenkov light dose monitoring device based on multi-channel imaging, which is characterized by including: a multi-channel camera beam splitter component that splits Cerenkov light. The beam splitter component is composed of RGB two Composed of a chromotropic beam splitter (2) and bandpass filter that allows the incident Cherenkov light signal from the zoom lens (1) to be redirected to the appropriate camera channel according to wavelength, and packaged in a three-tube color camera assembly Three independent iCCD modules, the red, green, and blue channels are equipped with red, green, and blue sensitive iCCD modules respectively. The three-channel images are spatially registered and then the three-channel images are fused to obtain the color Cherenkov light image. .

The lens in question is a 10-100mm f/1.6 zoom lens (1).

The beam splitting device includes two dichroic beam splitters (2), which respectively separate the blue band and the red band, the blue band and the red band and the filtered green band from the Cherenkov light signal. are transmitted to the iCCD module respectively through a band-pass filter.

The iCCD module is composed of red, green, and blue sensitive enhancers (3, 4, 5) and a CCD module (6).

The image synthesis is to generate an RGB color image through image registration and color correction of multiple grayscale images obtained from multiple channels.

As shown in Figure 2: A Cherenkov light dose monitoring method and device based on multi-channel imaging, the use includes the following steps:

The patient was treated in the supine position on the right side, so the multichannel Cherenkov light camera was mounted on a tripod against the left wall of the treatment room to prevent head occlusion caused by the left anterior oblique and right posterior oblique tangential areas. Patients were treated with 6MV X-rays, and the lighting conditions in the treatment room were the same as standard lighting levels.

A multi-channel camera was mounted on a tripod in the treatment room to acquire images, acquiring Cherenkov light images in 16-bit raw format. Temporal and spatial median filtering is performed using 5 frames and 5 × 5 pixel motion windows on each camera's FPGA, eliminating additional denoising or smoothing in post-processing;

A stack of 120 frames of darkfield images was acquired, and the average number of darkfield frames was calculated. For a given acquired data set, each of the three image stacks is frame averaged and subtracted from each averaged darkfield frame;

Using checkerboard-based geometric correction, a two-dimensional polynomial transformation is performed on the green and blue images to spatially align the three channels to obtain a three-channel image;

By combining the RGB three-color channels, a colored Cherenkov light image can be obtained.

Claims (4)

1. A Cherenkov light dose monitoring device based on multi-channel imaging, characterized in that it includes: a multi-channel camera beam splitter component that splits Cerenkov light, and the beam splitter component is split by RGB dichroic beams consists of a detector (2) and a bandpass filter that allows the incident Cherenkov light signal from the zoom lens (1) to be redirected to the appropriate camera channel based on wavelength, and three independent color camera components packaged in a three-tube color camera assembly iCCD module, the red, green, and blue channels are equipped with red, green, and blue sensitive iCCD modules respectively. The three-channel images are spatially registered and then the three-channel images are fused to obtain the color Cherenkov light image; its operation steps include: A multi-channel camera is installed on a tripod in the treatment room to acquire images. A three-channel Cherenkov light data set and a 120-frame dark field image stack are collected. Temporal and spatial median filtering is used on the FPGA of each camera to avoid additional denoising or smoothing in post-processing; Through the signal transmission system, the Cherenkov optical signal detected in real time by the optical detection equipment is wirelessly transmitted to the processor; In the processor, the average frame of the dark field image stack is calculated, and then the respective average frames are calculated from the red, green, and blue channel image stacks, and the corresponding average dark field frame is subtracted; Using checkerboard-based geometric correction, perform a two-dimensional polynomial transformation on the three-channel image and spatially align the three channels to obtain a three-channel image; By combining the RGB three-color channels, a colored Cherenkov light image can be obtained. 2. A Cherenkov light dose monitoring device based on multi-channel imaging according to claim 1, characterized in that the zoom lens is a 10-100 mm f/1.6 zoom lens (1). 3. A Cherenkov light dose monitoring device based on multi-channel imaging according to claim 1, characterized in that the beam splitter assembly includes two dichroic beam splitters (2), respectively Separation of blue and red bands from Cherenkov light signals. 4. A Cherenkov light dose monitoring device based on multi-channel imaging according to claim 1, characterized in that the iCCD module is composed of red, green and blue sensitive intensifiers (3, 4, 5 ) and CCD module (6).