Do You Know Single Photon Emission Computed Tomography Device?

1. 1What is nuclear medicine?

Nuclear medicine is a science that uses drugs labeled with radionuclides to diagnose or treat diseases. It is the product of medical modernization and the applied science of nuclear technology in the medical field.

Fig.1 Classification of nuclear medicine

The main features of nuclear medicine can be summarized by "molecules and targeting", where "molecular" refers to the research and diagnosis of nuclear medicine at the molecular level with high sensitivity; "Targeting" refers to the use of radioactive tracers for "precision guidance", which specifically binds to targets such as the location of the lesion to diagnose and even treat diseases more accurately and with high specificity. Therefore, nuclear medicine is often referred to as precision medicine.

Fig. 2 Molecular targeted therapy (Source: Baidu Encyclopedia)

Nuclide imaging is to use a ray detector to collect the nuclear rays emitted by radionuclides or their markers involved in tissue metabolism from the body surface, and to locate and quantitatively display their metabolic processes, so as to diagnose diseases. The classification of imaging is shown in Fig. 3.

Fig. 3 Classification of radionuclide imaging

 2. 2How SPECT works?

SPECT stands for Single-Photon Emission Computed Tomography. SPECT imaging is the introduction of radioactive tracers into the human body to detect and record the gamma rays emitted by the radioactive tracers introduced into target tissues or organs in the human body, and display them in the form of images. It can show the location shape, size and other anatomical structures of organs or lesions, and more importantly, it can provide information about the blood flow, function, metabolism, and receptors of organs and lesions at the same time, thus contribute to the early diagnosis of diseases (Fig. 4).

Fig.4 SPECT imaging schematic and features

3. 3Clinical application of SPECT

Currently SPECT is commonly used in whole body bone scan, thyroid function test and renal dynamic examination in China. From a global perspective, nuclear medicine equipment is very important for tumor disease, brain nervous system and cardiovascular system disease inspection. (Fig. 5)

Fig. 5 SPECT main application

• Skeletal system

For patients with malignant tumors, the whole body bone scan is used to detect whether there is bone metastasis, and a treatment plan is formulated to achieve the purpose of evaluating and monitoring the efficacy of tumor treatment. BHP6601 and BHP6608 SPECT produced by Hamamatsu Photon Technology can realize whole body bone scan examination, and the examination process is simple and effective. (Fig. 6)

Fig. 6 Bone scan image

【The images demonstrate multiple bone resorptions and extraosseous resorption at the thoracolumbar spine (arrows), ribs (filled arrows), stomach (open arrows), and diffuse metastatic calcification in the lungs.】

• Endocrine System
  

SPECT is mainly used for thyroid function and renal function tests, which can detect hyperthyroidism, distinguish between hot and cold nodules, and perform functional analysis through the curve of renal metabolism. The BHP6602 gamma camera of Hamamatsu Photon Technology has a good clinical application effect in the examination of thyroid function (Fig. 7).

Fig. 7 Thyroid imaging

（The image resolution of BHP6602 is significantly higher than other products, which can clearly identify the location of nodules） 

• Cardiovascular System

Radionuclide myocardial imaging has important clinical value in the diagnosis of coronary heart disease, risk stratification, detection of viable myocardium, and the diagnosis and treatment of many other heart diseases. The BHP6603 and BHP6606 SPECT of Hamamatsu Photon Technology can help diagnose the location, size and extent of myocardial infarction or ischemia (Fig. 8); evaluate the borderline lesions of coronary arteries; realize the efficacy evaluation and follow-up of patients with coronary heart disease after treatment, etc.

Fig. 8 Cardiac imaging

（The red arrow indicates the location of ischemic heart defect）

• nervous system

SPECT is also an effective early examination method for the brain nervous system. The application of domestic nuclear medicine in the brain nervous system, especially the examination of the SPECT equipment on the brain nervous system, is still in the early stage. It has been applied to the brain imaging examination for many years abroad, and it can basically distinguish and discover diseases such as Alzheimer's.

With the acceleration of population aging, brain diseases have increased, and the proportion of cognitive impairment, Alzheimer, Parkinson and other diseases has increased year by year with the progress of aging. Early diagnosis can be achieved through SPECT. Hamamatsu Photon Technology's BHP6606 Triple head SPECT (Fig. 9) has been mass producted and sold in Japan for  years and achieved good clinical appraises

Fig. 9 Brain scan image

（The image resolution of the BHP6606 is significantly higher than other general-purpose dual head SPECT）

Hamamatsu Photon TechnologyLangfang) Co., Ltd (BHL)is a wholly-owned subsidiary of Beijing Hamamatsu Photon Techniques INC.. BHL concentrates on the development of nuclear medicine imaging equipment for 22 years, keeps on researching of the systems and the applications, and provides integrated system, components and related services for medical institutions and enterprises engaging in the field of nuclear medicine. We are willing to incubate SPECT products with all partners, support the development of domestic nuclear medicine equipment, try our best to promote the development of medical business and serve for human health.