Computer tomography (CT) apparatus is a medical diagnostic equipment. The CT apparatus may use an X-ray to pass through a subject (e.g. a patient) and receive the X-ray that passes through the subject. A received X-ray may form an image rendering morphology of internal organs of the subject. In the CT apparatus, X-rays are generated and emitted by a CT tube which is also known as an X-ray tube.
The CT tube is actually a high-vacuum cathode-ray diode having a cathode and an anode, wherein a filament is deployed at the cathode. When the CT tube is in a work mode, a current may be provided to the filament through the cathode for heating the filament to generate a gathered free electron cloud. High voltage may be applied between the cathode and the anode, abruptly increasing an electric potential between the cathode and the anode. Owing to a strong electric field at high voltage, a free electron beam in an active state at the filament of the cathode may strike a tungsten target in a molybdenum base at the anode, and energy transformation may occur. Part of the electrical energy may be converted into X-rays and emitted through a window, and another part of the electrical energy may be converted into heat which is dissipated by a cooling system. The current provided to the filament at the cathode is called filament current. The voltage between the cathode and the anode is called tube voltage. The electrons generated by heating the filament may move at high-speed from the cathode to the anode under the high voltage potential, and form a current called tube current. The present disclosure pertains to controlling the filament current of the CT tube so as to implement X-ray radiation dose control of the CT equipment.
Neusoft Medical Systems Co., Ltd. (NMS), founded in 1998 with its world headquarters in China, is a leading supplier of medical equipment, medical IT solutions, and healthcare services. NMS supplies medical equipments with a wide portfolio, including CT, MRI, digital X-ray machine, Ultrasound, PET (Positron Emission Tomography), Linear Accelerator, and Biochemistry Analyzer. Currently, NMS' products are exported to over 60 countries and regions around the globe, serving more than 5,000 renowned customers. NMS' latest successful developments, such as 128 Multi-Slice CT Scanner System, Superconducting MRI, Linear Accelerator, and PET products, have led China to become a global high-end medical equipment producer. As an integrated supplier with extensive experience in large medical equipment, NMS has been committed to the study of avoiding secondary potential harm caused by excessive X-ray irradiation to the subject during CT scanning process.