A. Proton knife is used to destroy tumor by using the proton beam emitted from general physical high-energy gas pedal or medical proton gas pedal, and the ionization effect generated after entering the body, so that the tumor is irradiated with high dose, while the normal tissues around the tumor are protected, thus killing the tumor cells. Proton knife is suitable for lesions that are limited in scope, the surrounding normal tissues are sensitive and need special protection, the lesions and surrounding tissues are less active, and the lesions are clear in scope. Such as prostate cancer, ocular melanoma, glioma, pituitary tumor, meningioma, skull base sarcoma, skull base chordoma and other intracranial tumors, paraspinal tumors, etc. Contraindicated: lesions with greater normal tissue activity, lesions with unclear demarcation between normal tissues, or lesions that are more extensive. Why is the adverse reaction of proton knife small? 1.The traversal speed is very fast, only a few energy will be released in the traversal path, only when the treatment depth is reached will it suddenly decrease and stop, releasing a large amount of energy, the energy is suddenly released and suddenly decayed, so the radiation has little effect on the normal tissues in transit. 2.Because of the large mass of the proton, the scattering is less and the penumbra is smaller, which reduces the irradiation to the surrounding normal tissues. 3.The interaction between proton radiation and tumor tissue is mainly through collision with electrons outside the nucleus to transfer energy, and the maximum energy point is controlled at the tumor boundary by adjusting the energy to control the range depth, radiation direction and site. Why is the proton knife superior to conventional radiotherapy? Traditional radiotherapy uses X-rays, and the dose is built up and decayed in a relatively long distance and process, which causes more damage to normal tissues. Compared with conventional radiotherapy, proton knife has less damage to normal tissues, uniform dose distribution, better control of depth, direction and location, and better conformability of high dose area to tumor shape. While increasing the tumor dose, the damage to normal tissues is reduced. Particle knife 1.How to cut steadily and accurately A: Particle knife is a miniature radiation source precisely implanted into tumor tissue according to the shape of tumor. Through its continuous emission of low-energy Y-rays, the tumor tissue is subjected to destructive killing method. The main two isotopes of particles currently used for implantation are iodine (125I) and palladium (103Pd). The particles are implanted into the tumor, which can kill the tumor cells continuously and effectively; because of the high dose of radiation released by the particles, the tumor cells are killed through the continuous release of radiation around the clock; and because of its low energy and short range, it causes relatively little damage to the normal tissues and organs around the tumor. The radioactive particles commonly used in medical treatment are radioactive iodine particles with a diameter of 0.8mm and a length of 4.5mm sealed by titanium alloy shell. The number of radioactive particles used is calculated by determining the location and size of the tumor through CT or MRI examination. Under the guidance of ultrasound or CT, the particle implantation needle is punctured percutaneously into the tumor, and the radioactive particles are placed in a fully enclosed radiation-proof implantation device, and the particles are delivered to the tumor through the implantation needle. The radioactive particles are placed in a fully enclosed radiation-proof implantation device and delivered to the tumor through the implantation needle. 2.Where is the frontier of particle knife Advantages: low dose of particles, small area, continuous radiotherapy. Indications: Tumors that require preservation of important functional tissues or surgery that will involve important organs. Patients who refuse to undergo radical surgery; prophylactic implantation to prevent local or regional spread of tumor and enhance the effect of radical treatment; metastatic tumor lesions or postoperative isolated tumor metastases that have lost their surgical value; inoperable primary cases; poor external irradiation effect or insufficient external irradiation dose as a local dose supplement. The following cases are not suitable for particle knife: tumor located in cavity organs with the possibility of perforation or extensive adhesion with cavity organs; tumor of excessive size with extensive metastasis; tumor in thoracic or abdominal cavity with large amount of pleural fluid or ascites; advanced malignant tumor with systemic failure. 3.What are the advantages of particle knife compared with traditional radiotherapy? Usually, the traditional radiotherapy we know is carried out by irradiating to the tumor site through external radiotherapy equipment, and the radiation has to pass through the skin and some normal tissues and organs to reach the tumor, and these tissues will undergo unnecessary damage. Particle knife treatment is implanted radioisotope radiotherapy. The advantages of this method are: localized radiation therapy to the tumor, lower dose of radiation therapy, longer duration of treatment, less damage to surrounding normal tissues, and strong killing power to tumor cells. It can also avoid surgical trauma and has no serious toxic side effects. It is generally used as salvage treatment for traditional radiotherapy, which can improve the quality of life of tumor patients, reduce pain and prolong life time. 4. Will the implanted particles produce radioactive damage? Implanted particles are radioactive substances, which need to be used safely and reasonably without good quality assurance, and will damage normal tissues and cells. At present, medical radioactive particles will not be absorbed by the body into the blood to cause radioactive contamination of the environment, and are safe for patients, families and medical personnel. Neutron knife 1. What are the advantages of neutron knife? The full name of neutron knife is californium 252 neutron source automatic remote-controlled rear-loading treatment system. It is a large modern high-tech radiation therapy equipment that integrates multiple disciplines to treat tumors in human body cavities or tubes. It uses Cf252 neutron source as the treatment radiation source, and through remote control, it automatically guides and delivers the neutron source to the tumor site accurately through the specially designed source applicator, and then irradiates the tumor tissue locally with high dose according to the treatment plan precisely planned by the treatment planning system in advance to achieve the purpose of killing the tumor tissue and protecting the normal tissue to the greatest extent. Neutron radiation can effectively overcome the defect that conventional X-ray is insensitive to the lack of oxygen cells in malignant tumors, and its biological effect is stronger than that of ordinary rays such as deep X-ray, cobalt-60, gas pedal, etc. There is no or little repair of lethal or sublethal damage to cells after irradiation, and the recurrence rate is low, so it has a powerful effect of killing tumor cells directly, thus tumors with poor radiosensitivity and tumors in the middle and late stages and recurrence can still be treated after treatment. Therefore, tumors with poor radiosensitivity and intermediate and recurrent tumors can still achieve better results than conventional treatment. The neutron knife treatment process is safe, computer-controlled, automated and programmed. The treatment has little impact on the patient’s health and does not require a high level of physical fitness. The treatment adopts internal irradiation mode, the neutron source is close to the lesion site, and the high-dose neutron rays are focused on irradiating the tumor from the inside, which has great direct killing power to the tumor cells and little damage to the healthy tissues outside the tumor, so there are few complications after the treatment. 2.Does neutron knife have three heads and six arms? Neutron knife treatment adopts the internal irradiation method, the neutron source is close to the lesion, and the high-dose neutron radiation is focused on irradiating the tumor from inside, which has great direct killing power to the tumor cells, little dependence on oxygen in the tumor cells, little difference in radiosensitivity to cancer cells in different cell cycles, no or little lethal damage and sub-lethal damage repair, high tumor cure rate and low recurrence rate. And there is little damage to the healthy tissues outside the tumor. Neutron rays are difficult to obtain, while the damage to normal tissues is difficult to compensate. In addition, neutron knife is a new radiotherapy technology, which needs more verification. 3.With neutron knife, can we not operate? For the current tumor treatment, surgery is one of the fundamental treatment means, and neutron knife is only used as a salvage means for tumor treatment, and there are relatively few clinical studies. 4.What are the adverse effects of neutron knife? Neutron knife adopts internal irradiation, generally the dose to normal tissues is low and the toxic reaction is small, but the reaction of normal tissues after irradiation mainly varies according to the site of irradiation.