RADIATION & PERIAPICAL XRAY MACHINE.pdf

DXRY311: ROENTGENOLOGY PRELIMS: LECTURE 3, 4, & 5: RADIATION PHYSICS; PERIAPICAL X-RAY MACHINE; RADIATION BIOLOGY LECTURE BY: DR. CHRISTIAN M. BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 RADIATION PHYSICS Atom: basic build...

DXRY311: ROENTGENOLOGY PRELIMS: LECTURE 3, 4, & 5: RADIATION PHYSICS; PERIAPICAL X-RAY MACHINE; RADIATION BIOLOGY LECTURE BY: DR. CHRISTIAN M. BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 RADIATION PHYSICS Atom: basic building blocks of matter vs Cell: basic unit of life atom is composed of 3 components: o electron (-) o proton (+) o neutron (uncharged) ATOMS ® basic building blocks of matter Electron can move from one shell to another (from inner shell to outer shell) but it cannot exist in between shells By product: light Excitation: the electron is displaced (did not leave the atom) from one shell to another Ionization: incoming electron (moving) would travel and replace an electron (shell). An electron was dislodged (in K shell) and this will create radiation ® Electrons move in predetermined circular or elliptical shells or orbits around the nucleus ® Atoms in the ground state are electrically neutral because the proton and neutron: in the middle; makes up the nucleus number of positive charges (protons) is balanced by the number of surrounding the nucleus is the electron negative charges (electrons) ISOTOPES INTERACTIONS AT ATOMIC LEVEL ® atoms with the same atomic number (Z) but with different atomic ® The high-speed electrons bombarding the target are involved in two mass numbers (A) and hence different numbers of neutrons (N) main types of collision with the tungsten atoms: atomic number: number of protons 1. Heat producing collisions à heat is produced atomic mass: number of protons + number of neutrons 2. X-ray producing collisions à X-ray is produced isotope: stable form of an element unstable elements à radioisotope (it is because if an element is unstable, it tries to become stable by releasing radiation and once they have released enough radiation, that is the time that they will become stable) uses of radioisotope in medicine: treating cancer patients à cancer radiation therapy RADIOISOTOPES ® Unstable form of an element that emit radiation to transform into a more stable form Electrons move in a determined circular or elliptical shell Electron shells There is more heat produced 99% of the electrons will be converted to HEAT and only 1% Forbidden zone will be converted to X-RAY HEAT à the incoming electron is deflected by the cloud of PRODUCING outer-shell tungsten electrons, with a loss of small COLLISIONS energy, in the form of heat Incoming electron interacts with the outermost shell Electron shells: named as K, L, M, N, O shell Sub shells: o S: 2 o P: 6 o D: 10 o F: 14 o G: 18 X-RAY à the incoming electron penetrates the outer electron PRODUCING shells and passes close to the nucleus of the tungsten COLLISIONS atom Electron shells o K=S =2 Incoming electron interacts with the innermost o L = S, P =8 shell & nucleus o M = S, P, D = 18 o N = S, P, D, F = 32 o O = S, P, D, F, G = 50 C.C. SANTOS [DMD 3-Y2-3] 1 DXRY311: ROENTGENOLOGY PRELIMS: LECTURE 3, 4, & 5: RADIATION PHYSICS; PERIAPICAL X-RAY MACHINE; RADIATION BIOLOGY LECTURE BY: DR. CHRISTIAN M. BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 Yellow box: adult and pedo buttons Black box: teeth buttons (for anteriors, premolars, molars) THE PERIAPICAL X-RAY MACHINE Green box: PROPERTIES OF X-RAYS o 0.70 – exposure time (patient will be exposed for 7 APPEARANCE à x-rays are invisible and cannot be seconds) detected by any of our senses o (+) & (-) button= to adjust the exposure time MASS à x-rays have no mass or weight o Increase (+): if the patient is big because the film will be CHARGE ® X-rays have no charge light SPEED ® X-rays travel at the speed of light o Negative (-): if the patient is thin because there is too WAVELENGTH ® X-rays travels in waves and have short much radiation and the film will be dark and wavelengths with high frequency overexposed PATH OF ® X-rays travel in straight lines and can ® Time TRAVEL be deflected or scattered ® Kilovoltage FOCUSING ® X-rays cannot be focused at one point ® Milliamperage selectors CAPABILITY and always diverge from a point PENETRATING ® X-rays can penetrate liquid, solids, and EXTENSION ARM POWER gases ® Suspends the x-ray tubehead ® The composition of the substance ® Houses the electrical wires that extend from the control determines whether x-rays penetrate or panel to the tubehead pass through or are absorbed ® Allows for movement and positioning of the tubehead ABSORPTION ® X-rays are absorbed by matter ® The absorption depends on the atomic TUBEHEAD structure of matter and the wavelength Where X-ray is being generated of the x-ray IONIZATION ® X-rays interact with materials they CAPABILITY penetrate and cause ionization (dislodgement of electron) FLUORESCENCE ® X-rays can cause certain substances to CAPABILTY fluoresce, or emit radiation in longer wavelengths (e.g. visible light) EFFECT ON ® X-rays can produce an image in FILM photographic film EFFECT ON ® X-rays cause biologic changes in livng LIVING TISSUES cells PARTS OF X-RAY MACHINE ® Component parts ® Metal housing 1. Control panel ® Insulating oil 2. Extension arm ® Tubehead seal 3. Tubehead ® Xray tube ® Transformers ® Aluminum disks ® Lead collimator ® Position indicating device METAL à metal body of the tubehead HOUSING ® Surrounds the x-ray tube and transformers ® Filled with oil ® Protects the x-ray tube ® Grounds the high-voltage components CONTROL PANEL INSULATING à oil that surrounds the x-ray tube and OIL transformers inside the tubehead ® Prevents overheating by absorbing the heat created by the production of x- rays TUBEHEAD ® Aluminum or leaded glass covering of SEAL the tubehead that permits the exit of radiation from the tubehead ® Seals the oil in the tubehead and acts as a filter of the x-ray beam X-RAY TUBE ® Heart of the x-ray generating system This is where X-ray is produced On and off switch ® Cathode ® Anode C.C. SANTOS [DMD 3-Y2-3] 2 DXRY311: ROENTGENOLOGY PRELIMS: LECTURE 3, 4, & 5: RADIATION PHYSICS; PERIAPICAL X-RAY MACHINE; RADIATION BIOLOGY LECTURE BY: DR. CHRISTIAN M. BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 TRANSFORMER ® Device that alters the voltage of Unleaded glass window: this is where radiation will pass incoming electricity through ® Increase or decrease the voltage in an electrical circuit CATHODE à negatively charged ® Supply the electrons necessary to generate the x-rays Role: to produce the electrons Tungsten filament: responsible for producing the electron; tungsten has a high melting point; produces electrons when heated Focusing (molybdenum) cup: it focuses or directs the electrons towards the focal spot of the tungsten target; focuses the electrons into a narrow beam and directs the beam ALUMINUM ® Sheets of 0.5 mm thick aluminum across the tube towards he tungsten target DISKS placed in the path of the x-ray beam of the anode called focal spot ® Filter out the non-penetrating longer ANODE à positively charged wavelength xrays ® Consist of copper stem and target at which LEAD ® Would prevent radiation from passing the beam of high-speed electrons is COLLIMINATOR through direction ® Prevent the spread of radiation Function: to convert electrons into x-ray protons Tungsten target: converts the electron to x- ray protons; tungsten has a high melting point; converts the kinetic energy of the electrons generated from the filament into x-ray photons POSITION ® Open-ended, lead lined cylinder that Copper Stem: thermal conductor and INDICATING extends from the opening of metal dissipates heat DEVICE (PID) housing of the tubehead ® Aims and shapes the x-ray beam ® It is a glass vacuum tube in which all of the are has been ® 8,12,16 inches long removed ® Sometimes referred to as the cone ® Electrons produced in the negative cathode are accelerated in the positive anode TUNGSTEN à high atomic number § More efficient for production of x-ray ® High melting point § 99% of kinetic energy is converted to heat X-RAY TUBE ® Low vapor pressure § Precludes compromising the vacuum in the tube at high operating temperature ® Since the thermal conductivity of tungsten is relatively low, the tungsten target is frequently embedded in a large block of copper X-RAY GENERATING APPARATUS ® Electricity and electric current ® Electrical circuits ® transformers ELECTRICITY AND ELECTRIC CURRENT ® Electricity- energy that is used to make x-rays ® Electrical energy – consists of a flow of electrons through a conductor Heart of x-ray ® Electric current- flow of electrons It is where the radiation is being produced ® Amperage – measurement of the number of electrons Leaded glass housing: to prevent spreading of radiation to moving through a conductor other areas C.C. SANTOS [DMD 3-Y2-3] 3 DXRY311: ROENTGENOLOGY PRELIMS: LECTURE 3, 4, & 5: RADIATION PHYSICS; PERIAPICAL X-RAY MACHINE; RADIATION BIOLOGY LECTURE BY: DR. CHRISTIAN M. BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 ® Amperes or milliamperes – it is the measurement of ® Consists of x-rays of many current different energies and wavelengths ® Voltage- measurement of electrical force that causes ® Produced by: electrons to move from a negative pole to a positive one § Direct hit ® Volts or kilovolts- measurement of voltage ¾ Produced by the sudden ® Milliamperage (mA) adjustment- controls the amperage or stopping or braking of high- the no. of electrons passing through the cathode filament by speed electrons at a target increasing or decreasing it The moving electron has ® Kilovoltage peak (kVp) adjustment- controls the current directly hit the nucleus passing from the cathode to the anode Complete stop ® Circuit- path of electric current. Two electrical circuits are Law of conservation & used in the production of x-rays energy: the more energy is § Filament circuit (low voltage) – uses 3 to 5 volts. conserved; the more Controlled by the milliamperage radiation is produced § High voltage circuit- used 65,000 to 1000,000 volts More radiation is produced controlled by the kilovoltage settings Rarely happens § Near miss PRODUCTION OF X-RAYS ¾ Electron doesn’t hit the ® Electricity from wall outlet supplies the power to generate x- nucleus rays ¾ Electron is attracted towards ® When xray machine is turned on, the electric current enters (+) charged nucleus the control panel via the cord plugged into the wall outlet. ¾ The passage of electrons near ® Current travels from the control panel to the tubehead via the nucleus, which results in the electric wires in the extension arm electrons being deflected and ® The current (110-120) is directed to the filament circuit and decelerated step down transformer in the tubehead Moving electron has a shift in ® The transformer reduces the 110 or 220 entering line its direction because it was voltage to 3 to 5 volts attracted (different charges – ® Working voltage of the filament is 3 to 5 volts electron (-) and proton is (+)) ® When the filament circuit is activated, the filament heats up Slow and thermionic emission occurs CHARACTERISTIC ® Produced when a high-speed ® Thermionic emission is the release of electrons when RAD electron dislodges, an inner shell electric current passes thru the filament and heats up electron from the tungsten atom ® When the exposure button is activated, the electrons are - focus is on the and causes ionization of that atom accelerated from the cathode to the anode innermost electron ® Inner shell electron is replaced by ® The electrons strike the tungsten target and their kinetic shell a higher energy level electron energy is converted to x-rays and heat ® When the exposure button is activated, the electrons are X-RADIATION accelerated from the cathode to the anode PRIMARY à refers to the penetrating x-ray beam that is ® The electrons strike the tungsten target and their kinetic produced at the target of the anode and exits energy is converted to x-rays and heat the tubehead SECONDARY à refers to x-radiation that is created when TYPES OF X-RAYS the primary beam interacts with matter 1. General radiation (Bremsstrahlung – German word which SCATTER ® Form of secondary radiation that deflects means slowing down) after it hits matter 2. Characteristic radiation GENERAL RAD. à radiation produced when the (BREMSSTRAHLUNG) speeding electrons slow down because ® X-rays pass through the of their interactions with the tungsten patient without any interactions - focus on the target in the anode ® X-ray photons can be nucleus ® 70% of x-ray energy produced at completely absorbed by the patent the anode ® X-ray photons can be scattered C.C. SANTOS [DMD 3-Y2-3] 4 DXRY311: ROENTGENOLOGY PRELIMS: LECTURE 3, 4, & 5: RADIATION PHYSICS; PERIAPICAL X-RAY MACHINE; RADIATION BIOLOGY LECTURE BY: DR. CHRISTIAN M. BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 Radiosensitive: cells are killed easily by RADIATION BIOLOGY radiation Radioresistant: cells are not affected by high RADIOBIOLOGY doses of ionizing radiation ® It is the branch of biology concerned with the effects of ® By 1906, Bergonie and Tribondeau realized that cells were ionizing radiation on living systems most sensitive to radiation when they are: ® The biological effects of ionizing radiation originate 1. Rapidly dividing primarily from the damaged DNA of a cell or cells 2. Undifferentiated ® Everything around us contains, and always has contained 3. The greater the mitotic activity radioactive substances IONIZING There is dislodgement of electron SOURCES OF RADIATION RADIATION ® Radiation of sufficient energy to disrupt NATURAL à the three major sources of naturally occurring DNA strands radiation are: ® photons (X-rays, gamma rays) 1. Cosmic radiation: from the sun & outer ® particles (alpha, beta, neutron) space ® biologic effects of ionizing radiation 2. Terrestrial radiation: earth’s crust 1. useful but can be harmful 3. Internal radiation: sources of the human 2. burns and cellular damage body 3. principal hazard is the risk of cancer ARTIFICIAL ® Accounts for about 15% of the total induction (MAN- radiation burden 4. long term epidemiological studies of MADE) ® 97% of all man-made radiation is due to exposed populations demonstrated diagnostic medical (and dental exposures) potential for delayed induction of ® Dental and other medical x-rays malignancies ® Radiation used to diagnose diseases and for NON- The electron is not dislodged in the atom cancer therapy IONIZING and stays within the atom ® Industrial uses of nuclear technique RADIATION ® Consumer products such as luminous wrist watches, ionization smoke detector CHANGES IN BIOLOGIC MOLECULES ® Small amount released from coal and PROTEINS nuclear power plants NUCLEIC DNA à double stranded à more ACID radiosensitive RNA à singe stranded RADIOSENSITIVE Organisms that cannot tolerate high levels of ionizing radiation RADIORESISTANT Organisms that are capable of living in environment with very high levels of ionizing radiation RELATIVE RADIOSENSITIVITY OF TISSUE ® In general, the radiation sensitivity of tissue is: § Proportional to the rate of proliferation of its cells § Inversely proportional to the degree of cell differentiation ® A developing embryo is more sensitive to radiation during the early stages of cell differentiation ® An embryo/fetus is more sensitive to radiation exposure in the first trimester than in later trimesters RADIATION BIOLOGY HISTORY 1895 à Wilhelm Conrad Roentgen announces discovery of X-rays 1896 à (4 months later) reports of skin effects in x-ray researches 1902 ® First cases of radiation induced skin cancer reported 1906 ® Pattern for differential radiosensitivity of tissues Muscle cells: not easily affected by radiation (radioresistant) was discovered Lymphocytes: type of WBC They discovered that some cells are sensitive to Leukocytes: also known as WBC radiation à some cells can be killed by radiation Granulocytes: Basophils, Eosinophils, Neutrophils Blood forming organs are more radiosensitive C.C. SANTOS [DMD 3-Y2-3] 5 DXRY311: ROENTGENOLOGY PRELIMS: LECTURE 3, 4, & 5: RADIATION PHYSICS; PERIAPICAL X-RAY MACHINE; RADIATION BIOLOGY LECTURE BY: DR. CHRISTIAN M. BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 ® The potential biological effects and damages caused by by damaging chromosomes in a radiation depend on the conditions of the radiation somatic (biologic) cell exposure. ® Genetic defects are caused by damage § It is determined by: to chromosomes in a germ 1. Quality of radiation (reproductive) cell 2. Quantity of radiation ® There is no known existing threshold 3. Received dose of radiation for stochastic effects. One single photon for electron can produce the PROMT (ACUTE) & DELAYED EFFECTS effect. For this reason, a stochastic ACUTE Would manifest earlier or immediately effect is called a linear or zero- ® Effects including radiation sickness and threshold dose-response effect radiation burns, seen immediately after large doses of radiation delivered over short periods of time ® High doses delivered to healthy adults within short periods of time can produce effects such as blood components changes, fatigue, diarrhea, nausea, and death ® These effects will develop within hours, days, or weeks, depending on the amount of dose received ® The larger the dose, the sooner a given effect will occur DALAYED Would manifest at a later date Needs a threshold ® Effects such as cataract ALARA à As Low As Reasonably Achievable principle ® Cataracts PRINCIPLE Take x-ray if it is necessary § Threshold type of effect § When dose exceeding 2000-3000 mSv is RADIATION EFFECT ON ORAL TISSUE delivered to the eye ORAL MUCOUS If a patient is exposed to high doses of § May take months or years to appear MEMBRANE radiation à the mucosa becomes ® Cancer inflamed “mucositis” à will subside in 2 § No threshold yet months’ time à patient will not even notice the mucositis ® Oral mucous membrane contains a 2 TYPES OF BIOLOGIC EFFECTS FROM RADIATION basal layer composed of rapidly DETERMINISTIC Expecting that a patient would have this dividing. Radiosensitive stem cells EFFECT kind of side effect from the radiation ® Patient can experience redness and Example: you are expecting that a inflammation of the mucosa (mucositis) radiotech has a cataract because he is exposed to radiation ® Dose above the threshold determines occurrence ® Effects such as nausea, reddening of the skin or in severe cases, more acute syndromes that are clinically expressed TASTE BUDS Located at the dorsal part of the tongue in exposed individuals within a short Sensitive to radiation period of time after exposure to Most of the time the patient notices the radiation at high doses effect at the 2nd or 3rd week (loss of ® Are the result of various processes, taste acuity) à recovery is 60 to 120 mainly cell death and delayed cell days division, caused by exposure to high Lingual papillae: levels of radiation o Filiform: has no taste buds STOCHASTIC Non-threshold type ¾ Hairy tongue: elongation of filiform EFFECT Will occur by chance papillae; color depends on the diet Will occur even to those unexposed ¾ Management for hairy tongue: individuals removal of the cause (smoking, Example: patient has a cancer but only prolonged antibiotic use) exposed to radiation once o Foliate ® Those that occur by chance, appearing o Fungiform among unexposed people as well o Circumvallate ® According to a current knowledge of Taste: sweet, sour, salty, bitter molecular biology, a cancer is initiated If the anterior 1/3 of the tongue is radiated, the sweet and salty taste are affected C.C. 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BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 If the posterior 2/3 of the tongue is RADIATION Faster rate of progression than the radiated, the bitter and sour taste are CARIES normal caries because of the nature of affected the saliva which makes the teeth softer ® Dose in the therapeutic range cause ® Radiation caries is a rampant form of extensive degeneration of the normal dental decay that may occur in histologic architecture of taste buds individuals who receive a course of SALIVARY Major salivary glands: radiotherapy that includes the major GLANDS o Parotid à Stensen’s duct à pure salivary glands, the microflora under a serous pronounced change, rending them ¾ Most radiosensitive and they shrink acidogenic in the saliva and plaque when exposed to radiation ® 3 types of radiation caries: o Sublingual à Wharton’s duct à ¾ Superficial lesions attacking buccal, mixed but predominantly serous occlusal, incisal, and palatal o Submandibular à Bartholin’s duct à surface- most common mixed but predominantly mucous ¾ Caries involving primarily the Serous (watery) VS mucous (viscous) cementum and dentin in the Parotid: if compromised (shrink), the cervical region- lesions may saliva will be more viscous à will lead progress around the teeth to dry mouth/xerostomia circumferentially and result in loss Dry mouth/xerostomia à pH of the of the crown saliva drops and become acidic à from ¾ Dark pigmentation of the entire 6.5 to 5.5 crown- the incisal edges may be Xerostomia: prescription of artificial markedly worn saliva (prescribed ad libitum which ® The best method of reducing radiation means “at pleasure” or whenever the caries is daily application for 5 minutes patient wants; no overdose) of a viscous topical 1% neutral sodium ® There is a reduced volume of saliva in fluoride gel patients receiving radiation therapy ® Residual saliva becomes more viscous than usual, also has a pH value 1 unit below normal ® The mouth becomes dry (xerostomia) and tender; and swallowing is difficult and painful TEETH When the pH of the saliva drops, there will be tooth demineralization and they BONE Maxilla: composed of will be prone to caries cancellous/spongy bone Pedo patient: o Has a more blood supply o Exposed to radiation before o Healing is better calcification à tooth bulb will be Mandible: covered by a thick destroyed and no teeth will form cortical/compact bone (anodontia) o During radiation therapy, healing is o Exposed to radiation after compromised calcification à the root will not form if the patient is exposed to high levels or will not properly form of radiation, the blood vessels will tend ® Children receiving radiation therapy to to shrink; the osteoblasts are also the jaws may show defects in the affected permanent dentition such as patient is undergoing radiation therapy development, dwarfed teeth, or failure à tooth extraction à DO NOT DO to form one or more teeth EXTRACTION ® Exposure may retard or abort root bone decay because of radiation à formation, but the eruptive mechanism osteoradionecrosis of teeth is relatedly radiation resistant. osteonecrosis Irradiated teeth with altered root o osteoradionecrosis: cause: high formation still erupt. In general, the doses of ionizing radiation severity of the damage is dose o MRONJ: Medication Related dependent OsteoNecrosis of the Jaw ¾ Cause: medication being taken by the patient ¾ Most common drug is bisphosphonates (given to patients who are undergoing chemotherapy and to those who have osteoporosis) C.C. SANTOS [DMD 3-Y2-3] 7 DXRY311: ROENTGENOLOGY PRELIMS: LECTURE 3, 4, & 5: RADIATION PHYSICS; PERIAPICAL X-RAY MACHINE; RADIATION BIOLOGY LECTURE BY: DR. CHRISTIAN M. BELTRAN - DEPARTMENT OF CLINICAL DENTAL SCIENCES 3RD YEAR: 2ND SEMESTER – S.Y. 2022-2023 ® The primary damage to mature bone results from radiation-induced damage to the vasculature of the periosteum and cortical bone, which are normally already sparse ® The marrow tissue becomes hypo vascular, hypoxic, and hypo cellular ® The degree of mineralization may be reduced, leading to brittleness or little altered from the normal bone ® When the changes are so severe that bone death results and the bone is exposed, the condition is termed osteoradionecrosis ® The higher the radiation dose absorbed by the bone, the greater the risk for osteoradionecrosis ® Bisphosphonates – zoledronate, alendronate, pamidronate, risedronate, ibandronate, clodronate, etidronate ® RANKL inhibitor- denosumab ® Antiangiogenic agents – bevacizumab, sunitinib, sorafenib, pazopanib, axitinib ® M-TOR inhibitors- everolimus, temsirolimus MUSCULATURE If the patient is exposed to high doses of radiation, the muscles become stiff à usually starts 2 months after radiotherapy ® Radiation may cause inflammation and fibrosis resulting in contracture and trismus in the muscles of mastication ® Restriction in mouth opening usually starts about 2 months after radiotherapy I s completed and progresses thereafter DOSIMETRY ® Determines the quantity of radiation exposure or dose C.C. 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