Tumor radiation therapy is a method of treating malignant tumors using radiation such as alpha, beta, and gamma rays produced by radioisotopes and x-rays, electron rays, proton beams, and other particle beams produced by various types of x-ray therapy machines or gas pedals. Tumor radiation therapy (radiotherapy for short) is the treatment of cancer with radiation. Radiation therapy has experienced more than a century of development history. After the discovery of X-ray by Roentgen and radium by Madame Curie, it was soon used in the clinical treatment of malignant tumors, and radiation therapy is still an important local treatment method for malignant tumors. About 70% of cancer patients need to be treated with radiation therapy in the process of cancer treatment, and about 40% of cancers can be cured radically with radiotherapy. The role and status of radiotherapy in tumor treatment is becoming more and more prominent. Radiotherapy has become one of the main means of treating malignant tumors. Radiotherapy[1] Radiotherapy has a history of only a few decades, but has developed rapidly. Due to the use of ultrahigh-pressure therapy machines, the improvement of auxiliary tools and the accumulation of experience, the therapeutic effect has been significantly improved, and now it has become one of the most important means in cancer treatment. In China, more than 70% of cancers require radiation therapy, and in the United States, more than 50% of cancers require radiation therapy. Radiation therapy can be used for almost all cancer treatments, and for many cancer patients, radiation therapy is the only treatment that must be used. Radiotherapy indications The indications for radical radiotherapy are T1T2 stage tumors with a diameter of 5cm or less, T3 stage tumors with a diameter of more than 5cm and T4 stage tumors with infiltration of adjacent organs as the object of radical radiotherapy For patients with inguinal lymph node metastasis, it is also suitable to do radical irradiation, but lymph node metastasis is unfavorable to the local control Irradiation method and divided irradiation: the standard radiotherapy should cover the rectal and perineal areas, if there is a problem, it can be used for the treatment of cancer. If there are inguinal and iliac lymph node metastases should also cover these parts of the irradiation field on the edge of the lower end of the sacroiliac joints on both sides of the lower edge of the inguinal lymph nodes more in the small pelvis, including the perineum, the radiotherapy modality is often used to the two fields or three fields of four fields of irradiation, and sometimes can also be directly irradiation of perineal irradiation, should be avoided as far as possible before and after the irradiation of the small intestine to irradiation to the two field irradiation to 30 ~ 45Gy/1.8 ~ 2Gy irradiation, and then to the tumor to the second field irradiation to the small intestine to the second field irradiation. 2Gy irradiation followed by four-field irradiation of the tumor, such as rotational irradiation, etc. Additional irradiation of 9-20Gy/1.8-2Gy Additional irradiation of more than 45Gy irradiation of the small pelvis is carried out 4-6 weeks after the end of irradiation for the determination of the efficacy of the treatment There are also cases in which additional irradiation is carried out thereafter, but it is preferable to irradiate the tumor rapidly for the first time when the radical radiation therapy is carried out, so that it is possible to irradiate it as soon as possible for the complete course of the therapy. The minimum dose of external beam radio therapy (EBRT) is usually 45-50 Gy; a retrospective analysis showed a dose-effect correlation between dose and local control rate when EBRT was greater than 55 Gy. For stage III patients who did not undergo combination chemotherapy or partial resection only, the dose of EBRT could be increased by 19-25 Gy, bringing the total dose to 55 Gy. For those patients who do not have combination chemotherapy or only partial resection, EBRT irradiation dose can be increased by 19 to 25 Gy to reach a total dose of 55 to 67 Gy Irradiation dose compensation can take various forms, such as photo-quantum quadruple field irradiation direct perineal irradiation of photo-quantums or electrons, etc. interstitial brachytherapy, etc.192Ir(iridium) implantation brachytherapy is only applicable to the clinical individualized treatment of stage III long-term treatment. Complications of irradiation therapy mainly include anal ulcers, bleeding, necrosis, stenosis and anal fistulae, the incidence of which ranges from 10% to 30%, and 6% to 12% of patients need to undergo colostomy. These complications are mainly related to the high radiation dose, and it is not recommended to irradiate the inguinal area preventively Stereotactic Radiation Therapy (STRAT) Stereotactic Radiation Therapy (STRAT) is the use of special stereotactic devices, through the positioning of the CT or MΓI scanning, the use of focusing, and the use of the principle of focusing. Stereotactic radiotherapy is the use of a special stereotactic device to focus the radiation from each irradiation field or arc to the tumor area (target area) by using CT or MΓI scanning and positioning, while the normal tissues around the target area receive very little radiation. According to the characteristics of the tumor, single stereotactic radiosurgery (SRS) and fractionated stereotactic radiation therapy (SRT) can be performed. SRS is mostly seen in head γ-knife treatment, which is used for the treatment of intracranial arteriovenous malformations, cerebral dysfunction, brain metastasis, meningiomas, acoustic neuromas, craniopharyngiomas, pituitary tumors, and gliomas, etc. SRT is usually found in head-body X-knife, body γ-knife, and body γ-knife treatments. -knife and body γ-knife, which can be used not only for intracranial lesions, but also for the treatment of lung cancer, liver cancer, pancreatic cancer, adrenal gland tumors, and abdominal and pelvic tumors.SRS and SRT can be used individually or in combination with other radiotherapy methods. Stereotactic Radiotherapy[2] Five-year Survival Rate In order to count the survival rate of cancer patients and compare the advantages and disadvantages of various treatments, the medical profession adopts the situation where the prognosis of most of the patients is clearer as a statistical index, which is often referred to as the five-year survival rate by doctors. Five-year survival rate refers to the percentage of patients who survive for more than five years after various comprehensive treatments for a certain tumor. The expression of five-year survival rate has its certain scientific nature. After a certain tumor is treated, some of them may have metastasis and recurrence, and some of them may die because the tumor enters the advanced stage. Most of the metastases and recurrences occur within three years after radical surgery, accounting for about 80%, and a small number of them occur within five years after radical surgery, accounting for about 10%. Therefore, if various tumors do not recur within five years after radical surgery, there is little chance of recurrence, so the five-year survival rate is often used to indicate the efficacy of various cancers. Within five years after surgery, it is necessary to consolidate treatment and have regular checkups to prevent recurrence, and even if there are metastasis and recurrence, it can be treated early. In addition, three-year survival rate and ten-year survival rate are also used to express the efficacy of treatment. Edit this section Radiation source The radiation sources of radiotherapy mainly include radiation therapy machines and radionuclides. 1, X-ray therapy machine can be divided into X-ray therapy machine (10KV ~ 60KV), superficial therapy machine X-ray (60KV ~ 160KV) and deep X-ray therapy machine (180KV ~ 400KV) and other different energy rays. X-ray therapy machine’s shortcomings are low-energy, weak penetration, the skin affected by the amount of large, and is now less used. 2, medical gas pedal electronic induction gas pedal and electronic linear gas pedal. The former outputs high-energy electron beams, and the latter outputs high-energy electron beams (8~14MeV, mainly for superficial tumors) and high-energy X-rays (4~10MV, with strong penetrating power and less skin exposure). Medical gas pedals used in the most technologically fastest growing is the electron linear gas pedal. Medical electronic linear gas pedal (9) 3, radionuclides 226 radium as a natural source of radiation, because of its long half-life, has been replaced by artificial radionuclides 60 cobalt, 137 cesium, 192 iridium. Radionuclides can radiate a, ß, r three kinds of rays, clinically ß rays are only used for the treatment of superficial tumors, r rays are the main source of radiation therapy, energy 1.25 MeV. Radiation therapy machine made of 60 cobalt, because of the strong penetration of the r rays, the deep dose is high, and the skin receives a small amount of radiation, which is suitable for the treatment of deep-seated tumors. Edit This section Types There are two main forms of radiation therapy: external and internal. Certain patients receive both forms of radiation therapy. 1. External irradiation Radiation therapy External irradiation is also known as teletherapy. In this technique, high-energy rays or particles are directed at the cancer by a radiotherapy machine. Radiation therapy equipment used for external irradiation includes X-ray therapy machine, Co60 therapy machine and linear gas pedal, etc. Cobalt 60 therapy machine and linear gas pedal are generally used to irradiate the cancer at a distance of 80-100cm from the human body. Radiation therapy from the outside of the body has certain limitations, even in the case of sufficient irradiation, there is always a part of the tumor local recurrence. Internal irradiation Internal irradiation is also known as brachytherapy. This treatment technology sends high-intensity micro-shaped radioactive sources into the body cavity or inserts them into the tumor tissues with surgery to carry out close-range irradiation, so as to effectively kill the tumor tissues. The treatment technique involves a variety of delivery modalities such as cavernous tube, intertissue and intraoperative, and dressing. This technique is developing rapidly, and it allows a large number of patients who cannot be treated surgically and are difficult to control or recur with external irradiation to be re-treated with certain efficacy. And normal tissues are not over-irradiated to avoid serious complications, which has become a focal point in radiation therapy technology. In the past, the afterloading technology can only be used for gynecological tumor treatment, the latest generation of afterloading treatment machine has expanded the application of this technology to nasopharyngeal, esophageal, bronchial, rectal, bladder, breast, pancreatic, brain and other tumors. This new technology, in cooperation with other treatment methods, has gradually formed a very promising comprehensive treatment means, and all of them have achieved obvious results in application. Radioactive particle implantation for tumor treatment means that under the guidance of ultrasound or CT, radioactive particles can be precisely and uniformly placed around the tumor, and the maximum killing of tumor cells can be achieved through the continuous release of rays by the radioactive particles. Tumor radioactive particle placement therapy consists of three parts: ① Radioactive particles, such as 198Au, 125I and 103pd. ② Three-dimensional treatment planning system, which ensures that the spatial distribution of the particles after placement is consistent with the shape and size of the tumor. ③Particle insertion devices, including special insertion guns, catheters and isotope storage devices. Radioactive particles can be inserted intraoperatively or by ultrasound or CT-guided puncture. Radioactive particle insertion has the characteristics of small trauma, uniform dose distribution in the tumor target area and small damage to the surrounding normal tissues, low price, easy operation, etc. It has a broad application prospect in the clinic, and will benefit the tumor patients. The School of Radiation Therapy of Cooper University Medical Center in the U.S. uses macromolecular albumin (MAA) as “biological glue”, which can make 32p injected into the tumor body safely retained in the tumor. This method is very simple to operate, under the guidance of CT doctors with 1cm plastic handguard with biopsy needle inserted into the center of the tumor, and then use two sets of syringes, first injected with biogel MAA, and then injected with 32P, with the help of pressure to make injected from the center of the tumor to the edge of the diffusion. This technique is used for pancreatic cancer, intrahepatic metastases of colorectal cancer, and advanced head and neck malignancies that have lost the chance of surgery, and can cause the tumor to “melt away” for several months. All cells (cancerous and normal) grow and divide. But cancer cells grow and divide faster than many of the normal cells around them. Radiotherapy uses high doses of radiation produced by special equipment to irradiate cancerous tumors, killing or destroying cancer cells and inhibiting their growth, reproduction, and spread. Although some normal cells are also damaged, most recover. Unlike chemotherapy, radiotherapy will only affect the tumor and its surrounding areas, not the whole body. 1. The mechanism of radiation killing cancer cells People are more familiar with the way of surgery and taking medicine and injections to treat cancer because they can understand it intuitively, but they are not so clear about the role of radiation in killing cancer. The reason why radiotherapy can play an anti-cancer role is that radiation carries a special kind of energy called radiation. It is well known that radiation can induce cancer in the natural environment, and in the case of radiotherapy, radiation acts as a cancer “killer”. When a cell absorbs any form of radiation, the rays may directly interact with intracellular structures, directly or indirectly damaging cellular DNA. (I) Mechanisms of Radiotherapy Direct Damage DNA molecules are broken and crossed mainly by free radicals generated by rays acting directly on organic molecules. Indirect damage is mainly caused by the ionization of water in human tissues by rays, generating free radicals, which then interact with biological macromolecules, leading to irreversible damage. Both effects have equal importance. (ii) Tumor absorbed dose Since the function of radiotherapy is to cause changes in the structure and cellular activity of cancer cells through the transfer of energy between rays and cancer cells, or even to kill cancer cells, people are concerned about how much energy is absorbed in the tumor tissues, i.e., the absorbed dose of tumors, which is related to the efficacy of treatment. The nature of the rays is described by the quality and quantity of the rays: a. The quality of the rays: indicates the ability of the rays to penetrate the material, called the hardness of the rays, which is expressed in terms of the energy, such as MV, MeV; b. The quantity of the rays: indicates the intensity of the radiation, which is expressed in terms of Curie or Bekelel (Bq). The quality and quantity of rays are determined by the choice of different radiation sources (or radiation therapy machines). Interaction of the rays with matter. The nature of the absorbing medium: the degree of absorption varies considerably from one tissue (or tumor) to another. The unit of absorbed dose used to be rad, but now it is expressed by Gy, and 1Gy=100rad. During radiotherapy, a series of complex changes will occur in the tumor cell group (tumor body), some of which will be eliminated after death; some of which are just “hung up”, and will be revived in the future. Scientists summarize these changes as the 4 “R’s” of radiation therapy (because the first letter of the following 4 names are all R’s): Repair of Radiation Damage Cells with lethal damage will die. Cells with so-called sub-lethal or potentially lethal radiation-induced damage can be repaired and “sneak” back to life if given enough time, energy and nutrients. Oxygen and reoxygenation Oxygen plays an important role in the generation of free radicals by radiation, and the oxygenation status of cells has a great influence on the killing effect of radiotherapy. Radiotherapy has a great influence on the killing effect of radiotherapy. The killing effect of radiotherapy on oxygen-depleted cells is weakened, while the killing effect on oxygenated cells is obviously enhanced. Tumor tissues often have insufficient blood supply and a high ratio of oxygen-depleted cells, and some cancer cells can escape radiation damage, which is one of the common reasons for tumor regrowth and recurrence after radiotherapy. During radiotherapy, there are also cells that are originally hypoxic that may gain the opportunity to reoxygenate, thus increasing their sensitivity to radiotherapy. Redistribution of the cell cycle Cells of the cancer cell population are often in different cell proliferation cycles and are not uniformly sensitive to radiation. The most sensitive are M-phase cells, G2-phase cells are close to M-phase, and S-phase cells are the least sensitive. For cells in the G1 phase, the early G1 phase was poorly sensitive to radiation, but the late G1 phase was more sensitive. Radiotherapy-sensitive cells are removed; causing cell cycle changes (redistribution) in the cancer cell population. Cell repopulation Cell division will be accelerated after radiotherapy and tumor tissue grows faster. Considering that cells have a repopulating effect, radiotherapy needs to extend the course of treatment and increase the total irradiation to achieve more satisfactory treatment results. Understanding the above “movement” of cancer cells will help to improve radiotherapy technique and kill more cancer cells. Clinical application of radiotherapy (1) Radiotherapy Radiotherapy refers to the application of radiotherapy to completely and permanently eliminate primary and metastatic foci of malignant tumors. The amount of tumor given by radiotherapy needs to reach the radical dose. Radiosensitive and moderately sensitive tumors can be treated radically with radiotherapy. Radiotherapy also plays a major role in the comprehensive treatment regimen of such tumors. (ii) Palliative radiotherapy Palliative radiotherapy refers to the application of radiotherapy to treat recurrent and metastatic lesions of advanced tumors in order to improve symptoms. Palliative radiotherapy is sometimes called decompensated radiotherapy, which is used for the following situations: pain relief, such as pain caused by bone metastasis and soft tissue infiltration of the tumor. Relief of compression, such as obstruction of digestive tract, respiratory tract and urinary system caused by tumor. Stopping bleeding, such as hemoptysis caused by lung cancer or lung metastases. Promoting control of ulcerative cancer such as extensive skin cancer, oral cancer, breast cancer with ulcers. Improve the quality of life, e.g. to improve the quality of life by shrinking the tumor or improving the symptoms. (iii) Adjuvant radiotherapy Adjuvant radiotherapy is the application of radiotherapy as a part of comprehensive treatment to improve the treatment effect of patients by combining radiotherapy with surgery or chemotherapy. Before and after surgery or chemotherapy, radiotherapy can shrink the tumor or eliminate potential local metastatic lesions, improve the cure rate and reduce recurrence and metastasis. (IV) Tumor emergency radiotherapy Superior vena cava compression syndrome The clinical manifestations of patients are facial edema, cyanosis, aneurysm of chest wall veins and jugular veins, edema of upper limbs, respiratory difficulties, inability to lie down and rest, and so on. Tumors causing superior vena cava compression syndrome, lung cancer accounts for 75%～85%, malignant lymphoma accounts for 11%～15%, metastatic tumor accounts for 7%, and benign tumor accounts for 3%. At this time, radiotherapy should be given immediately to relieve the patient’s symptoms and alleviate the patient’s pain. After the symptoms are relieved, it is changed to conventional radiotherapy. Increased intracranial pressure Increased intracranial pressure will lead to displacement of brain parenchyma and formation of cerebral hernia in the direction of the weakest tension, resulting in fatal neurological injury and sudden death of the patient. Clinical manifestations include headache, vomiting, visual disturbances, and even mental confusion, lethargy, drowsiness, and seizures. Radiation therapy is best suited for the acute treatment of increased intracranial pressure caused by leukemic meningitis and multiple brain metastases. Simultaneous use of hormones and diuretics can relieve the patient’s symptoms and restore a certain degree of self-care. Spinal cord compression disorder Spinal cord compression disorder develops rapidly and it is difficult to return to normal once paraplegic. Primary or metastatic tumors are common causes of spinal cord compression. lung cancer, breast cancer, prostate cancer, multiple myeloma and lymphoma are most likely to metastasize to the spine, resulting in spinal cord compression. 95% of spinal metastases are extramedullary, so inoperable extramedullary tumors should be treated with radiation therapy as soon as possible, and high-dose corticosteroids should also be used to promote the subsiding of the edema and to prevent the occurrence of radiotherapy edema. This rapid irradiation method usually results in significant pain relief and symptomatic relief in most patients. Bone metastases Severe pain The pain-relieving effects of radiation therapy for bone metastases are both fast and good, and also have the effect of prolonging survival. Editorial Influences The degree to which a tissue responds to a certain amount of radiation is called radiosensitivity, and the degree to which different tissues and organs, as well as various tumor tissues, respond to the changes that occur after irradiation varies. Radiosensitivity is related to the proliferation cycle and pathological grading of tumor cells, i.e., proliferating active cells are more sensitive than non-proliferating cells, and the higher the degree of cell differentiation, the lower the radiosensitivity, and the higher the opposite. In addition, the oxygen content of tumor cells directly affects the radiosensitivity, for example, in early stage, when the tumor volume is small, the blood transport is good, and the lack of oxygen cells is less, but in late stage, when the tumor volume is large, the blood transport in the tumor is poor, and even there is necrosis in the center, then the radiosensitivity is low; squamous carcinoma growing locally has a better blood transport than that in the buttocks and limbs and has a high sensitivity; when the tumor locally combines with the infection and the blood transport is poor (the lack of oxygen cells is more), then the radiosensitivity decreases. Therefore, keep the irradiation site clean and prevent the disease from occurring. Therefore, keeping the irradiation site clean and preventing infection and necrosis are important conditions to improve the sensitivity of radiotherapy. Radiosensitivity of different tumors and normal tissues Relative sensitivity Tumor Normal tissue High Lymphoid tumors, leukemia, seminoma Lymphoid, bone marrow, testis, ovary, intestinal epithelium Medium high Squamous carcinoma: oral cavity, nasopharynx, esophagus, bladder, skin, cervical carcinoma, etc. Oral cavity, skin, cornea, hair follicle, sebaceous glands, esophagus, bladder, crystalline, vagina, uterus Medium Tumors of blood vessels and connective tissue General Connective tissue, neural connective tissue, growing cartilage and bone tissue Moderately low Most adenocarcinomas: breast, mucous glands, salivary glands, liver, kidneys, pancreas, thyroid, colon, fat, cartilage, osteogenic sarcoma Mature cartilage, bone tissue, mucosal salivary gland epithelium, sweat gland epithelium, nasopharyngeal epithelium, liver, kidneys, thyroid, renal epithelium Low Rhabdomyosarcoma, smooth muscle sarcoma Muscle tissues, brain, bone marrow Also. The sensitivity of radiation therapy is also affected by factors such as the degree of cell differentiation, clinical stage, previous treatment, the location and shape of the tumor growth, the presence or absence of local infection, the patient’s nutritional status, or the presence or absence of anemia. Editorial section: Nursing care of radiation reaction 1.Systemic reaction Due to the disintegration of tumor tissues and absorption of toxins, patients may have systemic reaction after irradiation for a few hours or 1~2 days, which manifests as weakness, fatigue, dizziness, headache, anorexia, nausea and vomiting, etc. Especially when irradiation of the abdomen and irradiation of a large area, the reaction will be heavier. Nursing measures: (1) should not eat before irradiation, in order to avoid the formation of conditioned reflex anorexia. (2) Completely lying down and resting for 30 minutes after irradiation. (3) Enter a light diet, eat more vegetables and fruits, and encourage drinking more water to promote the discharge of toxins. (4) Participate in group recreational activities or qigong to divert attention. In addition, check the blood image once a week, when the white blood cells drop to 4 × 109L, 80 × 109L below, need to give blood-boosting drugs, such as a significant drop in the blood image need to suspend radiotherapy. 2.Skin reaction The tolerance of the skin to radiation is related to the radiation source used, the irradiated area and the site. Cobalt 60 therapy machine and linear gas pedal produced by the r-ray and high-energy X-rays strong penetration, the amount of skin receptivity is small, the reaction is light; X-ray therapy machine produced by the low-energy X-rays and induction gas pedal produced by the electron beam skin receptivity is large, the reaction is heavy. Clinical large area irradiation or irradiation of skin folds and wet places, there can be a certain degree of skin reaction, skin reaction is divided into three degrees: (1) Ⅰ degree reaction: erythema, burning and itching sensation, continue to irradiate the skin from the bright red to dark red gradually, and later there is a desquamation, known as dry reaction. (2) Ⅱ degree reaction: highly congested, edema, blister formation, with exudate, vesicles, called wet reaction. (3) Ⅲ degree reaction: ulcer formation or necrosis, invading to the dermis, causing radioactive damage and difficult to heal. A few days or more after radiotherapy, the irradiation site can appear skin atrophy, capillary dilatation, lymphatic drainage obstruction, edema and dark brown spots, hyperpigmentation, called late reaction. Irradiation field skin protection measures: ① underwear should be soft, wide, strong moisture absorption. ② Keep the skin under the breasts, armpits, groin and perineum clean and dry, to prevent the dry reaction from developing into a wet reaction. ③ Irradiation field skin should be gently dabbed with warm water and soft towel, avoid using soap, do not apply alcohol, iodine, red mercury, ointment, and avoid hot and cold stimulation (such as hot water bags). The irradiation field should not be covered with adhesive tape, so as not to produce secondary rays from the contained zinc oxide (heavy metal) and aggravate the skin damage. ⑤ Head and face irradiation, prevent sunlight exposure. ⑥Use electric razor to avoid skin damage and infection. ⑦ Skin flaking period, do not use hands peel. ⑧ dry reaction, can be coated with 0.2% mint starch or lanolin to stop itching; wet reaction can be coated with gentian violet or hydrocortisone to expose the trauma; such as the formation of blisters, coated with boric acid ointment bandage for 1-2 days, to be absorbed by the exudate, and then exposure therapy. 3, mucosal reaction ⑴ stomatitis: oral mucosa irradiation can appear edema, congestion, ulceration, pain, decreased salivary secretion, dry mouth, to the emergence of pseudomembrane. Nursing measures: ①Keep the mouth clean, brush the teeth with a soft-bristled toothbrush after each meal, gargle with Dobel’s liquid 4 times a day, and change to 1.5% hydrogen peroxide when pseudomembrane appears. ② Change to a less crumbly diet, avoid using stimulating condiments and too cold and too hot food. ③If there is severe pain, you can spray 1% dicaine or dicaine sugar before meal. ④ Dry mouth can eat a small amount of acidic food to stimulate salivary secretion, and brush teeth with anti-dry mouth toothpaste. In addition, in order to prevent osteomyelitis or osteonecrosis in the late stage of radiation, teeth should be cleaned and treated for dental diseases before treatment, and teeth should not be extracted within 3 years after treatment. (2) Esophagitis: Mucosal congestion, edema and inflammation can occur after irradiation of the esophagus, which can aggravate the obstruction of the esophagus, resulting in difficulty in swallowing, pain, and increased mucus. The mouth and esophagus should be kept clean, and the esophagus should be rinsed by drinking warm water after each meal. High degree of obstruction requires gastrostomy or intravenous high nutrition. In middle and advanced esophageal cancer, especially ulcerative type, mucosal necrosis is easy to cause perforation; middle esophageal cancer has the possibility of penetrating into aorta and causing hemorrhage. Therefore, patients should be closely observed for choking, coughing, pain and change of pulse, so as to find out bleeding and perforation at an early stage in order to avoid delay in rescue. (3) Proctitis: when the whole abdomen or pelvis is irradiated, mucosal ulceration, abdominal distension, abdominal pain, diarrhea and so on may appear, and even necrotic tissues are dislodged, causing hemorrhage and intestinal perforation. Pay attention to the patient with or without bloody mucus stools, acute and recurrent radiation proctitis occurs, as well as intestinal perforation, hemorrhage and shock. (4) Cystitis: bladder irradiation can cause capillary dilation and symptoms of cystitis such as frequent urination, urinary urgency, hematuria, etc. The bladder shrinks in the late stage of radiotherapy. Patients should be encouraged to drink more water to naturally flush the bladder and prevent infection. Radioactive pneumonia and pulmonary fibrosis can occur after chest irradiation. Mildly asymptomatic, acute radiation pneumonia with high fever, chest pain, cough, shortness of breath and so on. Oxygen, hydrocortisone and antibiotics are needed immediately. Upper respiratory tract infection is the causative factor, and attention should be paid to keeping warm and preventing colds. Late radiotherapy can appear progressive pulmonary fibrosis, manifested as shortness of breath, dry cough, need to be treated symptomatically. 5, radioactive myelitis, spinal cord irradiation by a large dose of spinal cord injury will occur, mostly in the months to years after radiotherapy, the beginning of the performance of progressive, upward hyperalgesia, walking or holding weight weakness, such as the feeling of touching the electricity when the head is lowered, and gradually develop into limb movement disorders, hyperreflexia, spasm, to paralysis. Treatment needs to be given a large number of vitamin B neurotrophic drugs, hormones and vasodilators, with acupuncture, Chinese medicine; according to paraplegic patient care. Edit the basic principles of radiation protection In order to protect the staff from the harm of rays, the national regulations on radiation protection stipulate that the maximum permissible amount of 5Rem (the unit of measurement of the amount of radiation personnel received). The basic principles of radiation protection are: 1, reduce the irradiated dose The amount of radiation is directly proportional to the radioactive intensity of the source. Without prejudice to the work of the case, should minimize the operator’s exposure to the amount, so that it is within the permissible standards set by the state. 2, shorten the irradiated time irradiated with the contact time and increase. In order to ensure the quality of medical conditions, it is advisable to work quickly to reduce the residence time around it. 3, increase the radiation distance irradiation and the square of the distance inversely proportional to the amount. Long-handled tools or robots can be used to operate at a distance to reduce the amount of radiation, thereby playing a role in protecting the staff. 4, increase protection shielding The use of protective barriers can effectively reduce the amount of exposure. In addition, radiation workers should receive dosage supervision and do regular health checks. Edit this paragraph New progress in technology Radiation oncology has made many theoretical and technical breakthroughs due to the development of high technology. The following is a brief introduction to the progress of radiobiological sciences, bioequivalent dose super-segmentation, and three-dimensional intensity-modulated stereotactic radiation and other technologies. 1, progress in radiobiology 1) the progress of radiobiology to Linear-Quadratic model (Linear-Quadratic model) to explain the response in radiobiology, α / β coefficients to predict the dose-time efficacy of radiation therapy relationship for radiobiology has opened up a broader world. In recent years, the relationship between the cell cycle, i.e., the proliferative phase (G1-S-G2-M) and the quiescent phase (G0), has been studied in depth, and in this regard, the four Rs, i.e., repair, reoxygenation, redistribution, and repopulation have been proposed as a guideline for the research points to overcome the problems of hypoxia and so on in radiobiology. As the main points of research to overcome the problems of oxygen depletion in radiobiology, radiobiology has been advanced into effective research with a clear purpose and a strong focus. In recent years, after further understanding the relationship between apoptosis and mitosis in the study of cell repair and proliferation, we have proposed the ratio of apoptosis index (AI) to mitosis index (MI) (Apoptosisindex/Mitosisindex) to predict radiosensitization and prognosis, and to guide the development of spontaneous apoptosis and balance the resistance and resistance of various cells to radiation. It also guides the development of spontaneous apoptosis and the balance of anti-radiation and drug-resistance (i.e., Resistant RT and Resistant Chemotherapy) of various cells, and thus estimates the recurrence, researches the sensitization, and develops the new technology of super-segmentation and accelerated super-segmentation treatment, thus obtaining a lot of new results in scientific research and clinic, deepening the theoretical depth, opening up a new field, and promoting the progress of radiotherapy. (2) DNA and chromosome research In order to determine the tumor cells themselves radiation damage, chromosomes in the DNA chain in the break (single-stranded break SSB and double-stranded break DSB), the exact location of its break, and in the process, how the tumor cells to repair, but also to observe the error of the repair, as well as the absence of repair, etc., on the cells of the offspring of the role of the decision. Currently, clinical testing of the expression of multiple principles of DNA regulatory mechanisms can be used to distinguish between those that are meaningful and those that are sensitive, to establish methodologies and assays for clinical treatment and prognostic evaluation, and to guide the development of radiobiology, radiation physics, and clinical radiation oncology, making them more purposeful, targeted, and practical. Radiobiology from the cellular level has entered into the macromolecular level, from the pure laboratory transition to the preliminary stage of clinical application [5, 6]. 2, the progress of radiation physics technology (1) the realization of stereotactic treatment based on electronic computers to improve the accuracy, double helix CT and high-definition MRI appeared, so stereotactic treatment came into being, the current use of γ-knife, in a sense, a stereotactic radiosurgery process (Sterol Radiation Surgery, SRS), which through the focusing, targeting, and practical applications. It is a stereotactic radiosurgery (SRS) process, which can be performed by focusing, isocentric illumination, and giving the tumor super-conventional lethal dose treatment in a single short time or multiple times for a long time to achieve the purpose of destroying the cells in the tumor area. γ-knife makes use of about 30-200 cobalt sources, and irradiates the tumor (or the benign tumors, the foci of congenital malformations and other foci, which are generally about 1-2cmΦ) once or multiple times in a short distance from the different directions of the three-dimensional position under the condition of isocentricity, and then irradiates it. Irradiation, the total dose given exceeds the tolerance of the tumor and normal tissues, with accurate focusing method to make the dose of multiple 60Co sources concentrated in the target area, split beam focusing so that the surrounding normal tissues receive the dose is still in the possible tolerance, due to the use of computers, CT, as well as accurate three-dimensional design and positioning, and thus the shooting field boundaries can be sharp up to ± 2mm or less, to ensure that the normal tissues in the non-tumor area is safe. It is particularly effective when applied to benign small tumors and congenital malformations in the brain, and it has also achieved results when applied to the brainstem and other forbidden areas of life. However, at present, many units abuse the use of γ-knife and do not strictly control the indications, thus causing many sequelae and complications, and making the application of γ-knife deviate from the track of the initial design intent. In addition, the use of X-knife (gas pedal) and its application of computer for positioning, focusing and other technologies with γ-knife principle is similar, it is applied to head tumors (such as γ-knife) in addition to the application of the thorax, abdominal and pelvic regions, the scope of application is wider than the γ-knife, the application of the efficiency of γ-knife is better than the γ-knife. However, there are still many problems in the application of stereotactic irradiation (γ, X-knife) technology, such as distant complications in radiobiology, local control of tumors, and distant metastases are still unresolved, therefore, it is thought that relying on one such machine alone is not a complete solution to all the problems of radiation therapy. (2) Three-dimensional Conformal Radiation Therapy 3-Dimension Conformal Radiation Therapy (i.e., 3-D CRT), its theoretical and physical technology basis and γ-knife and so on are more or less the same. However, in recent years, special emphasis has been placed on the transition from planar two-dimensional positioning to stereoscopic three-dimensional positioning, and its corresponding grating (shading device) can change with the shooting field and conformal changes to accurately adapt to the shape of the tumor, so that the distribution of the high-dose area in the shape of the three-dimensional direction and the target area of the lesion is completely consistent with the conformity of the three-dimensional and three-dimensional is a problem of the two aspects of the conformity of the three-dimensional positioning is no way to achieve the conformity of the grating, there is no multiple leaves collimator, and no multiple leaves collimator, and no multi-leaf collimator. Without multi-leaf collimator, the conformal irradiation with body position and spatial morphology of tumor is also an empty word. In recent years, the development of stereotactic X-knife electronic computer chip design program breaks through the chip on the multi-leaf grating synchronization control of the conformal changes in the part, so that 3DCRT has stepped into the practical stage, which can be through the conventional segmentation, super-segmentation, accelerated super-segmentation, as well as the low-speed segmentation (Hypo fraction) and other therapeutic modalities to complete the general current Conventional radiotherapy machines (gas pedal, cobalt 60 machine, γ-knife, etc.) can not accomplish the task. Whether its accuracy, efficacy, complications are better than conventional treatment machines, some foreign people call it the conventional radiotherapy machine of the 21st century. It makes the shape of the shot field (single, multiple, motion, fixed) and the projection of the target area of the lesion to maintain consistency, multi-leaf grating on the shot field of the points in the output dose rate according to the requirements of continuous adjustment.
(3) Intensity Modulation Radiation Therapy (Intensity Modulation Radiation Therapy-IMRT) This technology is still used in the clinic, but domestic and foreign counterparts evaluate this technology as the mainstream of radiation therapy technology in the 21st century. Three-dimensional conformal therapy (3-DCRT) synchronized controllable multi-leaf grating, three-dimensional conformal positioning of this technology has become the basic technology in IMRT. However, the difference lies in the use of (1) inverse algorithm design (Inversereckon Planning), which is IMRT in addition to three-dimensional conformal, for more precise inserted the necessary steps, it is not only the front direction of the accurate dose calculation, but also from the reverse direction of the algorithm to validate and audit the use of high-energy X-rays, electron beams, proton beams, and other radiation sources, the field around the human body with a Continuous or fixed cluster beam, in the direction of rotating irradiation to achieve more accurate boundaries, so it can improve the intensity to achieve high output dose to adapt to the shape of the tumor, three-dimensional digital image reconstruction (3DRR-3Dimension Reckon-Picture Reconstruction) function, so that the target area of the three-dimensional image of the target area and other important organs and the image match, the appropriate distribution of dose It is clear at a glance whether the dose distribution is appropriate or not. a. Coronal, sagittal, cross-sectional images and dose distribution, but also to give any oblique section of the graphics and dose distribution, and can be displayed at any time to the treatment staff, designers and doctors, which makes the direction of the field of view of the view (BEV Beam-field Equation Vision) and the doctor’s reverse direction of the view (REV-Reaction Equation Vision) are consistent. Vision) are consistent. b, simulation selection – in the arrangement and design of the shooting field must have a simulation similar to the conventional analog positioning machine shooting field selection function, including collimator type, (independent, symmetric) and multi-leaf collimator that is, multi-leaf diaphragm (LMC-Multiple leaves collimator), the size of the placement of the shooting field stalls and wedge-shaped filter plate and so on. c, after the treatment plan is determined, the conditions will be entered into the CT simulation treatment (CT-Simulator), the simulator of CT should be able to accept the above conditions. d, verification, optimal program selection will be transferred to the treatment machine computer according to the above conditions, will be a variety of additional conditions such as racks, collimators, bed moving range, the size of the field of fire, multi-leaf grating blade movement and adjust the machine to match, so that the whole process is complete. The so-called intensity-adjusting and shape-adjusting radiation technology starts from the physical conditions on the fixed field of view, adjusts its accuracy to the highest, adjusts the planar two-dimensional accuracy to the three-dimensional more accurate direction, and adjusts the three-dimensional compensation in terms of illumination to the most accurate, giving the maximum amount of sufficient. From the diagnosis, design and implementation and a variety of compensation means, a variety of motion beam tuning, so that the shooting field boundaries sharp, clear boundaries, to achieve the highest degree of accurate positioning, the highest accurate dose to the target, high accuracy in the implementation of the intended plan, so that it can be more than the accurate treatment of SRT and SRS, but also to overcome the obvious shortcomings of SRT and SRS. (4) Image-guided radiation therapy-IGRT IGRT gas pedal This is the current direction of the development of tumor radiation therapy. Its purpose is to achieve the three principles of precise planning (TPS), precise positioning (IGRT) and precise treatment (IMRT) on the same treatment equipment. At present, American VARIAN, German SIEMENS, Swedish ELAKAT have the ability in this regard. There is a certain gap between China’s medical gas pedal and this, but we believe that we can catch up and surpass them soon. (1) Biological Equivalent Dose (BED-Biological Equralent Dose) In order to make the physical dose of the tumor center and other points of the dose difference (i.e., the dose inhomogeneity); and the physical dose and the difference of the biological effect (also known as the difference of the biological effect), the results of this double difference can be finally expressed in radiobiology on the unification of this double difference effect, called the biological effect. This double difference effect unification, called biological equivalent dose (BED), in the past, clinicians only based on experience and clinical effect to guess, it should achieve the radical dose to the tumor area, but also to the protection of the surrounding normal tissues, in order to make the BED applied to the clinical practice, in the past, the L-Q model α / β ratio can be roughly expressed this content. In the low-dose region starting section for cell killing and dose into a linear relationship (e-ad) for a single-target area α hit; as the dose increases the survival curve bends downward, when the cell survival and the dose into a square relationship (e-βd2), through the linear (α / β value of about 10Gy). Using this theory and laboratory results, the bioequivalent dose in the treatment is closer to the actual clinical treatment. Previously, the conventional split (five times a week, once a day, each dose of about 2Gy) applied in the treatment of this vector on the tumor control, it is a better bioequivalent dose, but not ideal. Therefore, in order to be close to the actual tumor, TCP (Tumor Contral Probability) and NTCP (Non Tumor Control Probability) have been proposed to measure the BED and tumor treatment probability with TCP/NTCP values. (2) Hyperfractionation (HF, Hyperfraction), Accelerated Hyperfraction, (AF, Acceleated Hyperfraction) and Hypofraction techniques in the clinic Previously, we commonly used conventional fractionation – i.e., five days per week, resting In the past, we usually use conventional fraction – that is, five days a week, two days of rest, once a day, each dose of about 2Gy, which has been used for decades is called conventional fraction (Convention fraction) The principle lies in the five days of radiation, two days of rest, a total of five times a week is a more appropriate treatment, which makes the tumor damage to reach a high level, but also makes it possible for normal cells in the target area to get part of the repair, the use of normal cells with the tumor cell The treatment is based on the “poor tolerance of normal cells and tumor cells”, but this kind of conventional fractionation (CF) is repeated once every 24 hours, no matter the dose is strengthened to 3Gy/times or higher, but there is a certain limit, and the normal tissues are weakly repaired if the continuous high dose of 4Gy/day is used, and the results of the clinical animal experiments have shown that the tumor cells start repairing in 4 hours after irradiation, so the daily treatment is more suitable. From the results of clinical animal test, we can see that the tumor cells have started to repair after about 4 hours of irradiation, therefore, once a day irradiation to the next day and then start again, the tumor cells which have been struck by the strike have already reached a certain level of recovery through the 4Rs (Repair, Re-oxidation, Re-distribution and Proliferation). If a certain amount of radiation is given between 3 and 24 hours of the repair cycle, it can aggravate the degree of damage and reduce the percentage of repair, resulting in more lethal damage, more double-strand breaks (DS), and a decrease in the number of cells blocked in the G1 phase. Based on this, over the past ten years at home and abroad to carry out the hyperfractionation (HF) treatment, the basic conditions for the irradiation twice a day, each interval of 4 to 6 hours each time the dose of 1.1 to 1.4Gy, and the rest of the conditions: the total dose, five days a week are no difference with CF. After more than a decade of trials and clinical observation has seen a local control, recurrence rate, survival rate than CF has a significant improvement, its recent side effects than conventional segmentation is significantly larger than the long-term damage and delayed reaction to the obvious sequelae and conventional segmentation is not a significant difference. These results have been double-blind randomized, single-blind randomized, non-randomized retrospective comparisons at home and abroad have achieved the same clinical results, and the actual results in animals have also been confirmed Accelerated Hyperfracton (AF) has the same principle and basic starting point and regulations as segmentation, but it is different in terms of the number of radiotherapy treatments per day, and the dosage of each treatment. It can be used at least 3 times a day (occasionally there are reports of 4 times), with an interval of 3~4 hours, and the sum of 3 doses is more than 3Gy (generally less than 4.5Gy), and its near-term and long-term efficacy has been better than that of CF since the 80s. Its near-term and long-term complications are the same as that of HF, and the near-term response is slightly greater than that of HF. However, no matter super-segmentation or accelerated super-segmentation, they are all based on the difference of radiobiological characteristics between tumor cells and normal cells and tissues, and the improvement of radiation therapy dose and local control cannot be separated from these basic conditions, therefore, this method still has certain limitations. In the United States Anderson Hospital and part of the trial of the so-called: auxiliary field super-segmentation treatment, (Hyperfraction Boost field), the method for the whole process of the second treatment every day, the first time the use of a larger dose, after an interval of 4 to 6 hours to join the auxiliary field, leaving the large field of lymphatic prevention of the area, the effect of which is to increase the primary foci of the blow, the lymphatic area The effect is to increase the blow to the primary foci and to increase the damage to the lymphatic area. As a result of several years of tests, the advantages are obvious, and the control of primary foci is very close to that of HF and AF, but the recent reaction is lighter, which is very popular in the clinic. (3) Conventional treatment Preoperative radiotherapy is still applied. In the past, it was mostly advocated that preoperative radiotherapy should be given 1/2～2/3 of the amount of conventional treatment for radical treatment before surgery, and because of the many intraoperative adhesions, some trials have reduced the amount of preoperative radiotherapy to 1/3 of the full irradiation, for example, the preoperative radiotherapy for esophageal cancer was reduced to less than 30Gy from GT30～40Gy in the past before surgery, and the observation of Japanese scholars did not find that it had increased distant metastasis, but the post-operation However, there were fewer complications and the survival rate was slightly improved, but the number of cases was too small and there was no randomization, so it was not very convincing. The application of super segmentation and accelerated segmentation for preoperative radiotherapy has been attempted, but there are many postoperative complications, which is consistent with its recent side effects, so at present there are more CF than HF or AF for preoperative treatment. 4, radiotherapy other new technology progress of radiotherapy technological and methodological research and basic theoretical research, which for the lack of oxygen cells and ray particles of radiation principles, radiobiological research provides some of the basis, such as the role of fast neutrons on the lack of oxygen cells, the use of high LEF rays of the Bragg peak of the superior physical and biological role of the utilization of the heavy particles, all have a great attraction to the radiation therapy technology, is still under continuous development. The use of proton gas pedals, which is the pioneer of heavy particle therapy, has been used in clinical practice. High LET radiation physical protection, long-term radiobiological effects, and after-effects should not be ignored. Precise positioning, precise design, precise application of treatment is the inevitable development trend of tumor radiotherapy technology, and is also the pursuit of the goal of radiotherapy work. The 21st century presents both opportunities and challenges to the new radiotherapy technology, so let’s face this situation and try our best to create the conditions to improve the grade and level, to catch up with the world’s advanced trend, and to reach a higher level. Many disciplines in tumor treatment cross each other and learn from each other. At present, high-dose chemotherapy or total body radiotherapy has been proposed in hematology and chemotherapy to kill malignant cells in the whole body, among which total body radiotherapy (TBI, Total Body Irradiation) has been applied more successfully in patients with bone marrow invasion of hematological diseases. For this reason, many people believe that for solid tumors that are easy to metastasize, such as undifferentiated carcinoma and small primary foci of cancer, the use of focal area plus total body radiotherapy and bone marrow transplantation or stem cell transplantation (Stem Cell Transplant) as a way to deal with this disease. At present, there are individual researches in foreign countries (Japan, the United States, France and Britain), in which the stem cells in peripheral blood or bone marrow are extracted and separated for preservation before treatment, and then radical treatment is given to the primary foci, and then TBI or HDC (Hyper-Dose Chemotherapy) is used to make the WBC reach close to 0, and then the original patient’s stem cells (peripheral blood or bone marrow) are returned to the laminar flow ward for transfusion, with the application of G-CSF. In addition, the patient’s stem cells (peripheral blood or bone marrow blood) will be infused back into the patient in the laminar flow ward, and the patient will be treated with G-CSF (Granulocyte Colony Stimulation Factor) to get through the infection of leukopenia and hope to be cured, so as to make the hidden malignant tumor cells potentially located in bone marrow and spleen have no place to hide, and to achieve the purpose of preventing metastasis and curing the disease. Due to the small focal poorly differentiated tumors, the cost of this approach is very high. Therefore, it is often not easy to be accepted by the patients, but at present there are still some successful examples of individual trials. As a new method, it has not been fully applied in clinical practice, but there is room for exploration and research value from theory and practice. However, it should be ineffective to apply this method to solid tumors that have been widely metastasized. Drawing from the side of this method to make the overall treatment of the tumor more effective is also a problem that radiotherapy should pay attention to. EDITORIAL What are the disadvantages of radiotherapy In tumor treatment, the main means are surgery, radiotherapy and chemotherapy; although radiotherapy has many advantages, there are also many disadvantages. Radiotherapy cannot reduce the toxic effects of chemotherapy, nor can chemotherapy reduce the damaging effects of radiotherapy. For example, chemotherapy inhibits the bone marrow throughout the body, and radiotherapy also produces localized bone marrow suppression, and patients are often unable to continue treatment because of the low blood phase of bone marrow suppression. When doing radiotherapy for thoracic tumors, the occurrence of radiation pneumonitis or pulmonary fibrosis and radiation pericarditis increased significantly in patients after chemotherapy, and sometimes the dose of radiotherapy had to be reduced, which increased the difficulty of radiotherapy. Chemotherapy is very toxic to liver, kidney and gastrointestinal tract, and the damage of radiotherapy to these parts is also quite big, so the dosage of radiotherapy is greatly restricted in comprehensive treatment, and it is difficult to increase the dosage for insensitive tumors, and the effect is poor. After chemotherapy, it also has a greater impact on the body’s immunity, and the physical condition is also greatly damaged, making it impossible to use a larger therapeutic field in radiotherapy. Therefore, chemotherapeutic agents with less toxicity to the organs under radiotherapy should be chosen as much as possible for comprehensive treatment.