BEAM DAMAGES — the pathological changes in an organism, bodies and fabrics developing as a result of impact of ionizing radiation. Mass L. items were observed in 1945 as a result of use of the USA of nuclear weapon. L. items can arise at radiation therapy, and also can be connected with violation of the rules of the accident prevention during the use of sources of ionizing radiation. At correctly picked up course radiation therapy (see) with rational fractionation of a dose, performing the general and local prevention possibility of L. the item considerably decreases. Strict observance of safety regulationss, antiactinic protection (see) and standards of permissible beam load (see. Marginal doses of radiation), use radiological protective processing equipment (see) exclude a possibility of professional L. item.
Character and degree of manifestation of L. items depend on a look ionizing radiation (see), sizes of its dose (see. Doses of ionizing radiation ), dosage rates of radiation (see), time factor of radiation (see), localization and the volume of the irradiated site, and also from such factors as gender and age of the patient, associated diseases, etc.
Biol, effect of impact of ionizing radiation and on healthy fabrics is defined on a tumor by hl. obr. a total absorbed dose, a dose for fraction, number of fractions and the general radiation time. In 1969 F. Ellis offered the concept of the nominal standard dose (NSD) corresponding quantitatively biol, to effect and measured in ret (Rada equivalent therapy). This dose is calculated on a formula:
NSD = D / (N 0,24 * T 0,11 ),
where D — a total dose in labor, H — number of fractions, T — time of treatment in days. Data on ionizing radiation doses in ret which can cause development of late beam complications in various bodies and fabrics are provided in the table. E.g., at radiation of the site of skin of 100 cm3 in a dose of 1700 ret ulcer and atrophic changes in it can develop in 1 — 5% of cases, at radiation in a dose of 2150 ret — in 25 — 50% of cases.
Patol, the changes arising sometimes at radiation can be divided into beam reactions and beam complications.
Understand set as the general and local beam reactions patol, the changes arising directly in time or soon after radiation and which are characterized by hl. obr. functional disturbances and, as a rule, reversibility of process. The neurohormonal and humoral changes which are combined with autoimmune processes are the cornerstone of the general beam reactions; at the heart of local beam reactions — inflammatory changes in fabrics with passing disturbance krovo-and lymphokineses, and also permeability of walls of vessels.
Beam complications are characterized by hl. obr. the structural changes arising in various terms depending on an ionizing radiation dose and radio sensitivity of the irradiated fabrics (see. Radiochuvstvitelnost ). Early beam complications can come to light in radio sensitive fabrics during radiation or arise after short stage of latency as, e.g., beam burns (see). Late beam complications develop in several months or years after radiation of hl. obr. owing to changes of vessels, and also the main substance, fibers and connective tissue cells, edge is exposed to a hyalinosis with reduction of number of cellular elements. At the same time damage of small vessels and capillaries causes frustration microcirculation (see), and defeat of an endothelium is expressed in disturbance of permeability and an integrity of an endothelial barrier. Changes in large vessels (an obliteration, a sclerosis, a hyalinosis, thrombosis, etc.) meet less often, as a rule, at influence of high doses of ionizing radiation or for the second time in connection with damage of surrounding fabrics.
The circulator hypoxia is a consequence of changes of vessels, edges aggravates necrotic and dystrophic processes, promotes oppression of regeneration and development of a secondary sclerosis of fabrics. An important role is played also by disturbances of an innervation and autoimmune processes which value increases in process of increase of destructive changes. The phenomena beam belong to pathogenetic factors of the general character toxaemia (see), caused by action on an organism of products of cellular disintegration and a radiolysis, disturbance of exchange processes in the irradiated site and beyond its limits.
A clinical picture
Klin, manifestations of the general beam reactions are expressed in weakness, dizziness, a headache, nausea, vomiting, etc. Local beam reactions in a look erythema (see), temporary epilations (see) or radioepithelitis (see) arise in the field of beam influence. Some manifestations of both local, and general beam reactions disappear further. At a zatikhaniye patol, changes process is estimated clinically as partial recovery with existence of the residual phenomena, napr, atrophies of skin and its appendages, a resistant epilation with teleangiectasias. Under the influence of various factors (mechanical, thermal, chemical, etc.) regress patol, changes can be broken: on the site which was affected by ionizing radiation in several months there are erosion, ulcers, inflammatory process escalates. At insufficiency of compensatory opportunities of an organism involution patol, changes do not happen, and process is characterized hron, the progressing current.
Early and late beam complications can be observed in various bodies and fabrics. Both at the general, and at local impact of ionizing radiation reaction of the hemopoietic system most often in the form of leucio-and thrombocytopenia which increased risk of emergence is available at low initial gematol, indicators, napr, in connection with earlier carried out chemotherapeutic treatment, as a rule, develops. The heaviest beam complications from the hemopoietic system are agranulocytosis (see) and Thrombocytopenic hemorrhagic syndrome.
At L. the item of skin develops in the beginning a dry radiodermatitis which sometimes passes in becoming wet with hypostasis and small erosion of a surface layer of skin (see. Radioepidermitis ). The erosive radiodermatitis proceeds with superficial, sometimes drain ulcerations, desquamation of an epithelium, limfangiity, sharp hypostasis of the subject fabrics, pains.
Afterwards the atrophy of skin and its appendages develops, teleangiectasias develop. In late terms in some cases there is beam ulcer (see), edges is located in the zone which was earlier exposed to the maximum radiation; it is characterized by a long current and tendency to a recurrence. More often beam ulcers develop on the sites having an insignificant layer of hypodermic cellulose, especially near a cartilaginous and bone tissue.
Indurative changes of hypodermic cellulose are observed more often after megavoltny radiation therapy and usually come to light in several months or years; at a palpation the sites of consolidation repeating a configuration of the field of radiation are found. In more hard cases soon after radiation in a zone of consolidation there are nagging pains, a hyperemia, swelled, limfangiit; further sclerous changes of hypodermic cellulose can develop.
L. items of a bone tissue are possible in various departments of a skeleton. Beam osteonecroses of jawbones which development some authors explain with activation of inflammatory process at caries of teeth are described. After radiation over - and subclavial zones concerning a breast cancer the osteonecrosis of a clavicle or edges with the subsequent patol, a change sometimes develops; the osteonecrosis of a head of a femur can be a consequence of irrationally planned radiation therapy concerning tumors of bodies of a small pelvis. After radiation therapy concerning, e.g., throat cancer there can be beam chondritis and perichondrites.
L. items of heart are more often shown in a look pericardis (see), frequency to-rogo later radiation of a thorax makes, according to some authors, apprx. 20 — 30%. Damage of a myocardium is characterized dystrophic and sometimes by focal necrotic changes.
L. the item of lungs — beam pneumonia — can proceed in an initial stage without expressed a wedge, pictures. Further patients complain of dry cough and an asthma at an exercise stress; radiological strengthening of the pulmonary drawing, expansion of a shadow of roots of lungs come to light. In more hard cases temperature increase and thorax pains is noted; rentgenol. the picture at the same time is similar with rentgenol, a picture melkoochagovy pneumonia (see). L. items of lungs quite often get hron, a current with development of a pneumosclerosis, fibrosis of a pleura; shift of a mediastinum and development of a pulmonary heart is observed.
L. items of sialadens are characterized by hl. obr. the dystrophic processes leading after a short phase of acute swelling and hypersecretion to reduction of secretion and change biochemical, composition of saliva. It promotes development of pathogenic microflora of an oral cavity and the progressing caries of teeth. In a mucous membrane of an oral cavity the epithelitis with the subsequent atrophic changes is observed: smoothing of nipples of language, decrease, a perversion or total loss of flavoring feelings, dryness in a mouth; development is possible periodontitis (see) with shaking and dedentition.
Beam esophagitis (see) can develop at radiation of a mediastinum that is observed, e.g., at radical radiation therapy concerning cancer of a gullet. Are most characteristic of an esophagitis of the complaint to a dysphagy and pains behind a breast. At rationally planned course of radiation therapy, as a rule, these phenomena disappear in several weeks after the end of treatment.
At local radiation of area of intestines swelling, abdominal pains, strengthening of a vermicular movement, diarrhea which can be short-term are noted and, as a rule, disappear in several days even at the continuing radiation. In certain cases these symptoms do not disappear or arise again sometimes in several months after radiation. At the same time the reactive inflammation of a mucous membrane of a small bowel develops, a cut is followed by disturbance of pristenochny digestion, a hypoplasia of a mucous membrane and development dysbacteriosis (see). During the progressing of process there can be superficial ulcerations with the subsequent sclerosis, scarring and development of a stenosis of a gut.
L. the item of a liver is shown in the form of hepatitis (see. Hepatitis, beam ).
Beam proctitis (see) — one of the possible complications arising in the course of radiation therapy concerning tumors of bodies of a small pelvis. At the same time tenesmus, mucifying from a rectum are noted, there are unpleasant feelings in the field of an anus which are, as a rule, most expressed at the end of a course of treatment and disappear after the termination of radiation. However in several months the beam proctitis can become aggravated again: there are pristupoobrazny pains, tenesmus, slime and blood in a chair; the mucous membrane of a rectum is inflamed, in hard cases its erosion and ulcerations are observed. Further as a result of a hyalinosis of connecting fabric of a wall of a gut there is a lymphostasis of a pararectal fat with the subsequent its sclerosis leading to fixing and a stenozirovaniye of a gut. In some cases there can be ulcers of a rectum which are located usually on its front wall and sometimes lead to formation of fistulas,
L. items of kidneys are shown in the form of acute or hron, nephrite (see), and also beam nephrosclerosis (see), at Krom substantial increase of the ABP can be noted. Acute beam nephrite develops, as a rule, not earlier than in half a year after radiation and is characterized by emergence of peripheral hypostases, oligurias, albumine - and cylindrurias, azotemias; in urine erythrocytes, leukocytes and cells of a renal epithelium are found. Sometimes symptoms of beam nephrite appear in 9 — 12 months after the termination of a course of radiation therapy.
Beam cystitis (see) can develop at radiation therapy of bodies of a small pelvis. At the same time in a wall of a bladder the hyperemia and hypostasis of a mucous membrane is noted, in hard cases there is ulcer cystitis with multiple hemorrhages and ulcerations that can lead to wrinkling and formation of vesical fistulas, strictures of mouths of ureters and urethras.
Heavy complications of radiation therapy are damages of c. the N the village of Klin, a picture of a beam myelitis is characterized by focal circulator frustration, short-term severe pains and unpleasant feelings in a backbone are noted.
At radiation therapy allergic reactions in the form of urticaria, an itch, local hypostasis, decrease in indicators of cellular immunity are sometimes observed.
For easing and elimination of manifestations of the general beam reactions is appointed by vitamins of group B, ascorbic to - that, the desensibilizing means; at nausea and vomiting aminazine, atropine, Dimedrol, etc. are shown.
At local beam reactions carry out antiinflammatory therapy by antibiotics, streptocides, use Galascorbinum, vitamin A, sea-buckthorn oil, linimentums with corticosteroids; for the purpose of stimulation of regenerator processes appoint methyluracil, retabolil, etc.
At early beam complications above-mentioned means apply is longer. Special methods of treatment at a pneumonitis are inhalations with Dimexidum, at cystitis — instillations of a bladder solution of methyluracil or Dimexidum. At proctites appoint disinfecting enemas, suppositories with anesthetics and a hydrocortisone, presakralny blockade. At a deep and resistant agranulocytosis radiation is stopped, the patient is transferred to sterile chamber (see. Chamber sterile ), where carry out treatment by antibiotics of a broad spectrum of activity, hemotransfusions and its components. In cases of a heavy esophagitis with perforation of a gullet it is recommended Mediastinotomy (see), an establishment of gastric fistula (see. Gastrostomy ).
Treatment of late beam complications includes fortifying therapy, prescription of antibiotics, the vitamin E, corticosteroids and other means stimulating an angenesis and normalizing processes of an immunogenesis, liquidating or weakening cicatricial and sclerous changes (Dimexidum, a lidaz, etc.). For the purpose of acceleration of rejection and a lysis of necrotic masses appoint proteolytic enzymes. By the main method of treatment of late L. and. skin, especially beam ulcers, surgical excision of the damaged fabrics and substitution of defect by means of skin plastics is; reconstructive plastic surgeries on circulatory and limf, vessels can be shown. In certain cases late beam complications apply operational treatment but to vital indications. So, e.g., at a beam stenosis with the developing impassability of intestines operation of a resection of an affected area of a gut is shown; at a proctitis from the outcome in a stenosis imposing of an unnatural anus is recommended. At a beam nephrosclerosis with development of a malignant hypertension carry out nephrectomy (see).
The forecast and Prevention
the Forecast at beam reactions, as a rule, favorable. At beam complications the forecast is more serious and depends on the physical characteristic of ionizing radiation, a way of radiation, and also localization, structure patol, process and radio sensitivity of body or fabric.
Prevention consists in rational planning of radiation, observance of the dozny restrictions developed on the basis of the fabrics and bodies given about radio sensitivity. Ways multifield, cross, mobile are offered radiations (see), use of protective blocks, filters, rasters, wedges; change of size of a single dose and duration of intervals between sessions of radiation, the split courses of radiation, ways of mechanical moving away of healthy fabrics from a tumor, creation of an artificial hypoxia (see. Oxygen effect ) and appointment the radio sensibilizing substances (see). Lack of ways of selective leading of ionizing radiation to cells of a tumor forces to look for a possibility of increase radiotherapeutic interval (see) and decrease in beam loads of healthy fabrics by means of inhibitors and radioprotectors (see). Appoint vitamins, anabolic hormones, nonspecific immunostimulators, carry out preliminary sanitation of the centers of an infection.
See also Post-radiation effects .
Table. POSSIBLE LATE BEAM COMPLICATIONS IN VARIOUS BODIES AND FABRICS which UNDERWENT RADIATION DEPENDING ON THEIR VOLUME OR EXTENT AND the IONIZING RADIATION DOSE [according to Ruben and Kazarett (R. of Rubin, G. Casarett)]
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