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Ionizing & Non-ionizing Radiation ENGR 4410 – INDUSTRIAL HYGIENE INSTRUMENTATION October 23, 2013 Janet M. Gutiérrez, DrPH, CHP, RRPT Radiation Safety.

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Presentation on theme: "Ionizing & Non-ionizing Radiation ENGR 4410 – INDUSTRIAL HYGIENE INSTRUMENTATION October 23, 2013 Janet M. Gutiérrez, DrPH, CHP, RRPT Radiation Safety."— Presentation transcript:

1 Ionizing & Non-ionizing Radiation ENGR 4410 – INDUSTRIAL HYGIENE INSTRUMENTATION October 23, 2013 Janet M. Gutiérrez, DrPH, CHP, RRPT Radiation Safety Program Manager Environmental Health & Safety

2 Speaker Biography Janet M. Gutierrez is manager of the Radiation Safety Program at The University of Texas Health Science Center at Houston. She is a Certified Health Physicist (CHP) and a Registered Radiation Protection Technologist (RRPT). In August 2011, she received a Doctorate in Public Health from the The University of Texas at Houston School of Public Health (UT SPH), and in 2005, she received a M.S. in Environmental Sciences / Industrial Hygiene from UT SPH as well. In 1998, Janet received a B.S. in Radiological Health Engineering from Texas A&M University in College Station, TX. Janet M. Gutierrez is manager of the Radiation Safety Program at The University of Texas Health Science Center at Houston. She is a Certified Health Physicist (CHP) and a Registered Radiation Protection Technologist (RRPT). In August 2011, she received a Doctorate in Public Health from the The University of Texas at Houston School of Public Health (UT SPH), and in 2005, she received a M.S. in Environmental Sciences / Industrial Hygiene from UT SPH as well. In 1998, Janet received a B.S. in Radiological Health Engineering from Texas A&M University in College Station, TX.

3 Speaker Biography Travis Halphen is a Safety Specialist in the Radiation Safety Program at The University of Texas Health Science Center at Houston (UTHSC- H). He is currently seeking his MPH in Environmental Health and Occupational Safety from University of Texas School of Public Health (UT SPH) and on May 2006 he received a Bachelors in Medical Physics from Louisiana State University. He was Assistant Radiation Safety Officer and Laser Safety Officer at Kansas State University from 2006 to 2008 before he ended up at his current position at UTHSC-H Travis Halphen is a Safety Specialist in the Radiation Safety Program at The University of Texas Health Science Center at Houston (UTHSC- H). He is currently seeking his MPH in Environmental Health and Occupational Safety from University of Texas School of Public Health (UT SPH) and on May 2006 he received a Bachelors in Medical Physics from Louisiana State University. He was Assistant Radiation Safety Officer and Laser Safety Officer at Kansas State University from 2006 to 2008 before he ended up at his current position at UTHSC-H

4 Ionizing vs. Non-ionizing Radiation Electromagnetic Spectrum Electromagnetic Spectrum

5 Radiation

6 Ionizing & Non-ionizing Radiation Units Units Decay Decay Inverse Square Law Inverse Square Law Shielding, HVL, TVL Shielding, HVL, TVL Instruments Instruments Dosimetry Dosimetry Biological Effects Biological Effects Regulations Regulations Practice Problems Practice Problems Types Biological Effects Regulations/Guides

7 What is Radiation? Radiation is energy transmitted by particles or electromagnetic waves Radiation is energy transmitted by particles or electromagnetic waves Radiation can be ionizing or non-ionizing Radiation can be ionizing or non-ionizing

8 Basic Concepts Radiation: energy Radiation: energy Ionizing vs. Non-Ionizing: enough energy to eject orbital electrons Ionizing vs. Non-Ionizing: enough energy to eject orbital electrons Radioactivity: excess nuclear energy Radioactivity: excess nuclear energy

9 Radioactivity Radioactivity is the natural property of certain nuclides to spontaneously emit energy, in the form of ionizing radiation, in an attempt to become more stable. Radioactivity is the natural property of certain nuclides to spontaneously emit energy, in the form of ionizing radiation, in an attempt to become more stable.

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11 Basic Concepts Radionuclide Radionuclide Nuclide Nuclide Isotopes have the same Z and a different A; Isotopes have the same Z and a different A; 10 C, 11 C, 12 C, 13 C, 14 C 10 C, 11 C, 12 C, 13 C, 14 C Isobars have the same A and a different Z; Isobars have the same A and a different Z; 14 N, 14 O; 15 N, 15 C 14 N, 14 O; 15 N, 15 C Isomers have the same A and the same Z; Isomers have the same A and the same Z; 99m Tc, 99 Tc 99m Tc, 99 Tc Isotones have the same N and a different A; Isotones have the same N and a different A; 14 O, 13 N, 12 C, 11 B, 10 Be, 8 Li 14 O, 13 N, 12 C, 11 B, 10 Be, 8 Li

12 Basic Concepts Types of radiation: Types of radiation: Alpha: particulate, massive Alpha: particulate, massive Beta: particulate, penetrating Beta: particulate, penetrating Gamma: electromagnetic, penetrating Gamma: electromagnetic, penetrating X-ray: electromagnetic, penetrating X-ray: electromagnetic, penetrating Neutron: particulate, no charge Neutron: particulate, no charge

13 Alpha (α) Needs at least 7.5 MeV energy to penetrate nominal protective layer of skin (7 mg/cm 2 ) Needs at least 7.5 MeV energy to penetrate nominal protective layer of skin (7 mg/cm 2 ) Most α less than this energy, so can not penetrate skin Most α less than this energy, so can not penetrate skin Range in air Range in air Range (cm) = 0.56E for E< 4 MeV Range (cm) = 0.56E for E< 4 MeV Range (cm) = 1.24E-2.62 for E> 4 MeV Range (cm) = 1.24E-2.62 for E> 4 MeV

14 Beta (β) Need at least 70 keV energy for beta to penetrate nominal protective layer of skin Need at least 70 keV energy for beta to penetrate nominal protective layer of skin β ave = 1/3 β max β ave = 1/3 β max Range in air Range in air Range is ~ 12 ft / MeV Range is ~ 12 ft / MeV Bremsstrahlung for high energy beta & high Z material Bremsstrahlung for high energy beta & high Z material Ex. P-32 and Lead Ex. P-32 and Lead

15 Gamma (γ) Photoelectric Photoelectric Compton Scattering Compton Scattering Pair Production Pair Production Photon Photon X-ray X-ray Gamma ray Gamma ray

16 Neutrons (n) Often expressed in n / cm 2 sec (flux) Often expressed in n / cm 2 sec (flux) Thermal neutrons = eV Thermal neutrons = eV Slow neutrons = 1 eV – 10 eV Slow neutrons = 1 eV – 10 eV Fast neutrons = 1 MeV – 20 MeV Fast neutrons = 1 MeV – 20 MeV Relativistic neutrons = > 20 MeV Relativistic neutrons = > 20 MeV U-238 & U-235 U-238 & U-235

17 Shielding Examples

18 Shielding for Multiple Types of Radiation High Energy Betas High Energy Betas Bremstrahlung Bremstrahlung Neutrons Neutrons Gammas Gammas

19 Units Activity: Curie (Ci) 3.7 x disintegrations per second Activity: Curie (Ci) 3.7 x disintegrations per second SI: Becquerel 1 dps SI: Becquerel 1 dps Exposure: Roentgen Exposure: Roentgen SI: C/kg SI: C/kg Absorbed Dose: Rad (Roentgen Absorbed Dose) Absorbed Dose: Rad (Roentgen Absorbed Dose) SI: Gray, 1Gy = 100 Rad SI: Gray, 1Gy = 100 Rad Risk: Rem (Roentgen Equivalent Man), Rad x QF Risk: Rem (Roentgen Equivalent Man), Rad x QF SI: Sievert, 1 Sv = 100 Rem SI: Sievert, 1 Sv = 100 Rem

20 Quality Factors

21 Half-life - the amount of time required for 1/2 of the original sample to decay The half-life is constant for each radionuclide and varies due to the nuclear structure. Half-life

22 Radioactive Decay Is the process by which the amount of activity of a radionuclide diminishes with time. Examples:

23 Radioactive Decay Formula Variables Variables A Activity at time t A Activity at time t A 0 Original Activity A 0 Original Activity t Time t Time Decay Constant Decay Constant T 1/2 Half Life Constants Constants ln e e

24 Concepts Radioactive Decay: A = A o e -λt Radioactive Decay: A = A o e -λt A = λN A = λN λ = / T 1/2 λ = / T 1/2 Inverse Square Law Inverse Square Law Shielding I = I o Be - t Shielding I = I o Be - t

25 Annual US Average Dose from Background Radiation was Total US average dose equivalent = 360 mrem/year Total exposure Man-made sources Radon Internal 11% Cosmic 8% Terrestrial 6% Man-Made 18% 55.0% Medical X-Rays Nuclear Medicine 4% Consumer Products 3% Other 1% 11%

26 Annual US Average Dose from Background Radiation Now is 625 mrem National Average Dose is US is 625 mrem, with medical being the largest type of increase.

27 Ionization of Gas – Radiation Detector A = recombination A = recombination B = ionization B = ionization C = proportional C = proportional D = limited proportional D = limited proportional E = Geiger Muller E = Geiger Muller F = continuous discharge F = continuous discharge

28 Monitoring Instrumentation Instrumentation Gas filled Gas filled Solid scintillator Solid scintillator Liquid scintillation Liquid scintillation

29 Monitoring Dosimeters Dosimeters Film badges: beta, gamma, x-ray Film badges: beta, gamma, x-ray Permanent record Permanent record Subject to fading Subject to fading Thermoluminescent dosimeter (TLD): beta, gamma, x-ray Thermoluminescent dosimeter (TLD): beta, gamma, x-ray No permanent record No permanent record Can be used for long term use Can be used for long term use Pocket ion chamber: gamma, x-ray Pocket ion chamber: gamma, x-ray Immediate readout Immediate readout Shock sensitive Shock sensitive

30 Biological Effects Radiation Effects on Cells: Radiation Effects on Cells: Somatic (early, delayed) & Somatic (early, delayed) & Genetic Dose Responses Genetic Dose Responses Linear, Linear Quadratic, Threshold Linear, Linear Quadratic, Threshold

31 Stochastic and Non-stochastic Effects Stochastic effects Stochastic effects Dose increases the probability of the effect Dose increases the probability of the effect No threshold No threshold Any exposure has some chance of causing the effect Any exposure has some chance of causing the effect Cancer Cancer Non-stochastic effects Non-stochastic effects Dose increases the severity of the effect Dose increases the severity of the effect Threshold Threshold Effects result from collective injury of many cells Effects result from collective injury of many cells Reddening, cataract, skin burn Reddening, cataract, skin burn

32 Biological Effects Assumptions Used for Basis of Radiation Protection Standards Assumptions Used for Basis of Radiation Protection Standards No Threshold Dose, Risk with Given Dose Increases With Increasing Dose Received, Acute vs. Chronic Exposures Not Considered, i.e. Repair No Threshold Dose, Risk with Given Dose Increases With Increasing Dose Received, Acute vs. Chronic Exposures Not Considered, i.e. Repair

33 Biological Effects Prenatal Exposures Prenatal Exposures Law of Bergonie & Tribondeau (1906): Law of Bergonie & Tribondeau (1906): Cells Tend to be Radiosensitive if They Have Three Properties: Cells Tend to be Radiosensitive if They Have Three Properties: A) Have a High Division Rate A) Have a High Division Rate B) Have a Long Dividing Future B) Have a Long Dividing Future C) Are of an Unspecialized Type C) Are of an Unspecialized Type

34 Most and Least Radiosensitive Cells Low Sensitivity Mature red blood cells Muscle cells Ganglion cells Mature connective tissues High Sensitivity Gastric mucosa Mucous membranes Esophageal epithelium Urinary bladder epithelium Very High Sensitivity Primitive blood cells Intestinal epithelium Spermatogonia Ovarian follicular cells Lymphocytes

35 Acute Radiation Syndromes Occurs if specific portions of body are exposed Occurs if specific portions of body are exposed Not likely unless major organs involved Not likely unless major organs involved 3 ARS syndromes: 3 ARS syndromes: Hematopoietic (blood/bone marrow) Hematopoietic (blood/bone marrow) rad rad Treatment: transfusions, antibiotics, bone marrow transplant Treatment: transfusions, antibiotics, bone marrow transplant Gastrointestinal (intestinal lining) Gastrointestinal (intestinal lining) rad rad Death likely if dose >1000 rad Death likely if dose >1000 rad Treatment: make individual comfortable Treatment: make individual comfortable Central Nervous System (brain) Central Nervous System (brain) 2000 rad or more 2000 rad or more Death likely within days Death likely within days Treatment: make individual comfortable Treatment: make individual comfortable

36 LD 50 for Humans Dose of radiation that would result in 50% mortality of in the exposed population within 30 days of exposure with NO medical treatment Dose of radiation that would result in 50% mortality of in the exposed population within 30 days of exposure with NO medical treatment LD 50 for Humans is 300 to 500 rad LD 50 for Humans is 300 to 500 rad

37 Risks of Radiation Exposure Low level (< 10,000 mrem) radiation Low level (< 10,000 mrem) radiation Only health effect: cancer induction Only health effect: cancer induction Average occupational dose to research and lab medicine personnel: <10 mrem/yr Average occupational dose to research and lab medicine personnel: <10 mrem/yr Amount is comparable to: Amount is comparable to: 6 cigarettes/yr 6 cigarettes/yr Driving 1,000 miles Driving 1,000 miles Living in a stone or brick home for 2 months Living in a stone or brick home for 2 months

38 Regulations / Guidelines NRC NRC Agreement States Agreement States NCRP NCRP ICRP ICRP ALARA Program ALARA Program

39 Exposure Limits Regulations: NRC 10 CFR 20 Regulations: NRC 10 CFR 20 Note old: Note old: Whole body: 1.25 rem/quarter Whole body: 1.25 rem/quarter Skin: 7.5 rem/quarter Skin: 7.5 rem/quarter Extremities rem/quarter Extremities rem/quarter New: New: Committed Dose Equivalent (CDE) Committed Dose Equivalent (CDE) Dose to a particular organ: Dose to a particular organ: Internal + External 50 rem Internal + External 50 rem

40 Exposure Limits Committed Effective Dose Equivalent (CEDE) Committed Effective Dose Equivalent (CEDE) Dose to a particular organ or organs with weighting factor: Dose to a particular organ or organs with weighting factor: Internal + External 5 rem Internal + External 5 rem Deep Dose Equivalent (DDE) Deep Dose Equivalent (DDE) Dose at a depth of 1 cm: Dose at a depth of 1 cm: Internal + External 5 rem (Eye 15 rem) Internal + External 5 rem (Eye 15 rem) Shallow Dose Equivalent (SDE) Shallow Dose Equivalent (SDE) Dose to skin or extremity: Dose to skin or extremity: External 50 rem External 50 rem

41 Exposure Limits Total Effective Dose Equivalent (TEDE) Total Effective Dose Equivalent (TEDE) Sum of dose from external and internal, including weighting: Sum of dose from external and internal, including weighting: Internal + External 5 rem Internal + External 5 rem Effective Dose Equivalent Effective Dose Equivalent Dose to organ or organs over one year period Dose to organ or organs over one year period Total Organ Dose Equivalent Total Organ Dose Equivalent Dose to organ from both internal and external: Dose to organ from both internal and external: Internal + External 50 rem Internal + External 50 rem Exposure to Fetus (Declared Pregnancy).5 Rem/9 months Exposure to Fetus (Declared Pregnancy).5 Rem/9 months

42 Other Useful Information 6CE rule 6CE rule Efficiency = c/d, usually in percent Efficiency = c/d, usually in percent Effective half life: Effective half life: Stay time = dose / dose rate Stay time = dose / dose rate REMEMBER UNITS! REMEMBER UNITS!

43 Internal advisory body for ionizing radiation Internal advisory body for ionizing radiation ICRP Publications (examples) ICRP Publications (examples) ICRP 84, Pregnancy and medical radiation ICRP 84, Pregnancy and medical radiation ICRP 84, Pregnancy and medical radiation ICRP 84, Pregnancy and medical radiation ICRP 85, Interventional radiology ICRP 85, Interventional radiologyICRP 85, Interventional radiologyICRP 85, Interventional radiology ICRP 86, Accidents in radiotherapy ICRP 86, Accidents in radiotherapyICRP 86, Accidents in radiotherapyICRP 86, Accidents in radiotherapy ICRP 87, CT dose management ICRP 87, CT dose managementICRP 87, CT dose managementICRP 87, CT dose management ICRP 93, Digital radiology ICRP 93, Digital radiologyICRP 93, Digital radiologyICRP 93, Digital radiology

44 National Council on Radiation Protection and Measurements formulate and widely disseminate information, guidance and recommendations on radiation protection and measurements which represent the consensus of leading scientific thinking publication of NCRP materials can make an important contribution to the public interest. NCRP 148 – Radiation Protection in Veterinary Medicine NCRP 138 – Management of Terrorist Events Involving Radioactive Material* NCRP 134 – Operational Radiation Safety Training NCRP 120 – Dose Control at Nuclear Power Plants NCRP 115 – Risk Estimates for Radiation Protection

45 Control Programs for Sources of Radiation Sealed Sources Radiation-Producing Machines Radioisotopes Radioactive Metals Criticality Plutonium

46 Control Programs for Sources of Radiation Operational Factors Employee Exposure Potential External Hazards Internal Hazards Records

47 Common Radionuclides Sealed sources Sealed sources Cs-137, Co-60, Ir-192, Am-241, Kr-85, Sr-90, Po-208 Cs-137, Co-60, Ir-192, Am-241, Kr-85, Sr-90, Po-208 Liquid radioactive material for research Liquid radioactive material for research P-32, P-33, S-35, H-3, C-14 P-32, P-33, S-35, H-3, C-14

48 Radiation Practice Problems Ionizing Radiation

49 Radiation Practice Problems 1. Iodine-131 has a radiological half life of 8 days. If a source originally contained 25 mCi how much remains after 18 days? 1. Iodine-131 has a radiological half life of 8 days. If a source originally contained 25 mCi how much remains after 18 days?

50 Radiation Practice Problems 2. Two measurements are taken on an unknown radiation source. The first was 1.3 mCi, and the second, taken 15 minutes later, was 0.05 mCi. What is the half life of this material? 2. Two measurements are taken on an unknown radiation source. The first was 1.3 mCi, and the second, taken 15 minutes later, was 0.05 mCi. What is the half life of this material?

51 Radiation Practice Problems 3. What is the exposure rate from a 15 Ci Cs-137 source at a distance of 1 foot? (Cs- 137 gamma energy MeV) How about 10 feet? 3. What is the exposure rate from a 15 Ci Cs-137 source at a distance of 1 foot? (Cs- 137 gamma energy MeV) How about 10 feet?

52 Radiation Practice Problems 4. How long can a worker stay 10 feet away from a 15 Ci Cs-137 source without exceeding an administratively established quarterly dose limit of 1250 mrem? 4. How long can a worker stay 10 feet away from a 15 Ci Cs-137 source without exceeding an administratively established quarterly dose limit of 1250 mrem?

53 Non-ionizing Radiation

54 What is Radiation? Radiation is energy transmitted by particles or electromagnetic waves Radiation is energy transmitted by particles or electromagnetic waves Radiation can be ionizing or non-ionizing Radiation can be ionizing or non-ionizing

55 Definition Non-Ionizing Radiation = Radiation that does not cause ionization Non-Ionizing Radiation = Radiation that does not cause ionization Types of non-ionizing radiation include: Types of non-ionizing radiation include: 1. Ultraviolet (UV) light 2. Visible light 3. Infrared (IR) light 4. Microwaves 5. Radiowaves

56 Lets Review – The Atom In their normal state, atoms are electrically neutral (no net charge) In their normal state, atoms are electrically neutral (no net charge) # protons = # electrons An atom that has gained or lost electrons is called an ion An atom that has gained or lost electrons is called an ion Positive and negative charges cancel

57 The Ionization Process 1. An in-coming photon interacts with an orbital electron 2. The electron is ejected from the atom, and the atom gains a net positive charge. Incident photon Ejected electron

58 Non-Ionizing Radiation Non-ionizing radiation is electromagnetic in nature: Non-ionizing radiation is electromagnetic in nature: This means it has characteristics of both waves and particles This means it has characteristics of both waves and particles However, non-ionizing radiation behaves primarily as a wave However, non-ionizing radiation behaves primarily as a wave

59 Electromagnetic Spectrum The electromagnetic spectrum covers an entire range of electromagnetic radiation The electromagnetic spectrum covers an entire range of electromagnetic radiation Which of these are considered to be non- ionizing? Which of these are considered to be non- ionizing?

60 Electromagnetic Spectrum Non-ionizing

61 Types of Non-Ionizing Radiation Ultraviolet (UV) light Ultraviolet (UV) light Visible light Visible light Infrared (IR) light Infrared (IR) light Microwaves Microwaves Radiowaves Radiowaves

62 Non-Ionizing Radiation Terms Terms Terms Energy Energy Frequency Frequency Wavelength WavelengthWavelengthFrequencyEnergy m 3x10 26 Hz 1.24x10 12 eV m 3x10 18 Hz 1.24x10 4 eV m 3x10 14 Hz 1.24 eV 10 2 m 3x10 6 Hz 1.24x10 -8 eV

63 Ultraviolet (UV) Light Ultraviolet light has a wavelength on the order of nanometers (nm) Ultraviolet light has a wavelength on the order of nanometers (nm) This is the shortest wavelength of all non- ionizing radiations This is the shortest wavelength of all non- ionizing radiations

64 Ultraviolet (UV) Light Ultraviolet light cannot be seen by the human eye Ultraviolet light cannot be seen by the human eye It is divided into 3 regions It is divided into 3 regions UVA (most energetic) UVA (most energetic) UVB UVB UVC (least energetic) UVC (least energetic)

65 Sources of Ultraviolet Light UV light is emitted naturally by the sun and stars UV light is emitted naturally by the sun and stars It is produced artificially by electric lamps and light bulbs It is produced artificially by electric lamps and light bulbs

66 Is Ultraviolet Light Dangerous? All UV light can damage skin and eyes All UV light can damage skin and eyes Over-exposure can lead to sunburn and various kinds of cancers, including melanomas Over-exposure can lead to sunburn and various kinds of cancers, including melanomas It can also lead to weakening It can also lead to weakening of the immune system of the immune system

67 Is Ultraviolet Light Dangerous? UV damage to fibrous tissue is often described as photoaging UV damage to fibrous tissue is often described as photoaging Photoaging makes people look older because their skin looses its tightness and it wrinkles Photoaging makes people look older because their skin looses its tightness and it wrinkles

68 UV Effects by Region UV-A ( nm) UV-A ( nm) Pigmentation of skin or suntan Pigmentation of skin or suntan UV-B ( nm) UV-B ( nm) Erythemal region Erythemal region Sunburn of skin Sunburn of skin Absorbed by cornea of eye (welders flash) Absorbed by cornea of eye (welders flash) UV-C ( nm) UV-C ( nm) Bacterial or germicidal effect Bacterial or germicidal effect

69 Protective Measures Ensure that skin and eyes are adequately protected (sunscreen, sunglasses, clothing) Never look directly at a source Operate UV lamps in light-tight conditions

70 Visible Light The wavelength of visible light ranges from nanometers The wavelength of visible light ranges from nanometers Visible light occupies the smallest segment of the electromagnetic spectrum Visible light occupies the smallest segment of the electromagnetic spectrum

71 Visible Light Visible light is comprised of various colors The separation of visible light into its different colors is known as dispersion

72 Visible Light Each color is characteristic of a different wavelength Each color is characteristic of a different wavelength

73 Black vs. White Technically speaking, black and white are not colors at all Black is the absence of color White is the combination of all colors

74 Visible light health effects Retinal burns Retinal burns Color vision Color vision Thermal skin burns Thermal skin burns

75 Infrared (IR) Light The wavelength of infrared light ranges from microns The wavelength of infrared light ranges from microns When an object is not quite hot enough to radiate visible light, it will emit most of its energy in the infrared When an object is not quite hot enough to radiate visible light, it will emit most of its energy in the infrared

76 Sources of Infrared Light Any object which has a temperature above absolute zero radiates in the infrared Any object which has a temperature above absolute zero radiates in the infrared Even objects we think of as being very cold, such as an ice cube, emit infrared light Even objects we think of as being very cold, such as an ice cube, emit infrared light

77 Sources of Infrared Light Even humans and animals emit infrared radiation

78 Visible Light vs. Infrared Light Some animals can see in the infrared Some animals can see in the infrared These images give an idea of how different the world would look if we had infrared eyes These images give an idea of how different the world would look if we had infrared eyes

79 Is Infrared Light Dangerous? Heating of tissues in the body is the principal effect of infrared radiation Heating of tissues in the body is the principal effect of infrared radiation Excessive infrared radiation can result in heat stroke and other similar reactions, especially in elderly or very young individuals Excessive infrared radiation can result in heat stroke and other similar reactions, especially in elderly or very young individuals

80 IR Effects by Region IR-A (0.75 – 2.5 nm) IR-A (0.75 – 2.5 nm) Penetrates skin to some extent Penetrates skin to some extent Penetrate eyes to retina Penetrate eyes to retina IR-B (2.5 – 5 nm) IR-B (2.5 – 5 nm) Almost completely absorbed by upper layers of skin & eyes Almost completely absorbed by upper layers of skin & eyes IR-C (5-300 nm) IR-C (5-300 nm) Thermal burns on skin & cornea Thermal burns on skin & cornea Cataracts (glass blowers) Cataracts (glass blowers)

81 Microwave Radiation The wavelength of microwave radiation ranges from about 10 microns to 1 meter The wavelength of microwave radiation ranges from about 10 microns to 1 meter Microwaves have very low energies and very long wavelengths Microwaves have very low energies and very long wavelengths

82 Microwave Radiation Microwave radiation has many uses, including: Microwave radiation has many uses, including: Cellular phones Cellular phones Highway speed control Highway speed control Food preparation Food preparation

83 Limit for Microwave Ovens 5 mW/cm 2 at 5 cm from surface 5 mW/cm 2 at 5 cm from surface

84 Is Microwave Radiation Dangerous? Exposure to very high intensity microwaves can result in heating of tissue and an increase in body temperature (thermal effects) Exposure to very high intensity microwaves can result in heating of tissue and an increase in body temperature (thermal effects) At low levels of exposure, the evidence for production of harmful effects (non-thermal effects) is unclear and unproven At low levels of exposure, the evidence for production of harmful effects (non-thermal effects) is unclear and unproven

85 Is Microwave Radiation Dangerous? Currently, exposure limits are based on preventing only thermal effects Further research is needed in order to learn more about non-thermal effects

86 Radiofrequency (RF) Radiation The wavelength of RF radiation (radiowaves) is greater than 1 meter The wavelength of RF radiation (radiowaves) is greater than 1 meter

87 Radiofrequency (RF) Radiation Both microwaves and radiowaves are used in communication Both microwaves and radiowaves are used in communication As a result, there is considerable overlap between what is identified as a radiowave and what is identified as a microwave As a result, there is considerable overlap between what is identified as a radiowave and what is identified as a microwave

88 Is RF Radiation Dangerous? As with infrared light and microwave radiation, the primary health effects of RF radiation are considered to be thermal As with infrared light and microwave radiation, the primary health effects of RF radiation are considered to be thermal RF radiation may penetrate the body and be absorbed in deep body organs without the skin effects, which can warn an individual of danger RF radiation may penetrate the body and be absorbed in deep body organs without the skin effects, which can warn an individual of danger

89 Static Magnetic Field Effects at Levels Below 0.5 mT and Greater Than 0.5mT Nuclear Magnetic Resonance Imaging (NMR)

90 Static Magnetic Fields Introduction Static Magnetic Fields Static Magnetic Fields Nuclear Magnetic Resonance Imaging Nuclear Magnetic Resonance Imaging Increasingly used in Biomedical Research Increasingly used in Biomedical Research in vivo analysis in vivo analysis effectively displays soft tissue contrasts effectively displays soft tissue contrasts MRI is unobstructed by bone MRI is unobstructed by bone

91 Safety Concerns with Static Magnetic Fields Attraction of Loose Ferromagnetic Materials Attraction of Loose Ferromagnetic Materials Surgical Implants Surgical Implants torqued, dislodged or rotated torqued, dislodged or rotated Pacemaker Interference Pacemaker Interference Typically Seen Above 0.5 mT (5 Gauss) Typically Seen Above 0.5 mT (5 Gauss)

92 SMF Exposure Limits / Guidelines ICNIRP ICNIRP 200 mT 200 mT Whole body (averaged for day) Whole body (averaged for day) 5000 mT 5000 mT Limbs/extremities (ceiling) Limbs/extremities (ceiling) 40 mT 40 mT Continuous general public exposure Continuous general public exposure US FDA CDRH US FDA CDRH 4000 mT 4000 mT Routine Patient Ceiling Routine Patient Ceiling ACGIH 60 mT {2000 T} Whole body (8hr-TWA) {Ceiling} 600 mT {5000 T} Limbs (8hr-TWA) {Ceiling} 0.5 mT Medical electronic devices

93 NMR Mapping 0.5 mT

94 Issues with Static Magnetic Fields < 0.5 mT: Space constraints impacts all involved Space constraints impacts all involved Concerns of stopping attention at levels below 0.5 mT Concerns of stopping attention at levels below 0.5 mT Impacts finite radiation protection programs resources Impacts finite radiation protection programs resources Facility Incompatibilities Facility Incompatibilities

95 SMF Affects Below 0.5 mT

96 SMF Problems Frequently Occurred Screen jitter Screen jitter Other electronic interference Other electronic interference Perceive Problem = Risk Perceive Problem = Risk Dynamic Situation Dynamic Situation Can lead to other problems Can lead to other problems

97 SMF Recommendations Move General Public limit farther back Move General Public limit farther back Move equipment to lower field levels Move equipment to lower field levels Solicit worker concerns Solicit worker concerns Map field strengths to near background levels Map field strengths to near background levels Routine assessments encouraged Routine assessments encouraged

98 SMF Recommendations (cont.) Area postings / brochures Area postings / brochures Educate workers about anticipated interferences Educate workers about anticipated interferences

99 SMF Conclusion Be aware of potential equipment effects below 0.5 mT Be aware of potential equipment effects below 0.5 mT Equipment incompatibilities may result in personnel management difficulties Equipment incompatibilities may result in personnel management difficulties

100 A Quick Recap… 5 types of non-ionizing radiation include: Ultraviolet (UV) light Visible light Infrared (IR) light Microwaves Radiowaves

101 What is a Laser? A device that produces light LASER stands for Light Amplification by Stimulated Emission of Radiation

102 Laser Applications Consumer Products Consumer Products CD Players Laser Pointers Laser Printers

103 Laser Applications Medical- eye surgery, therapy for Carpel Tunnel Syndrome Medical- eye surgery, therapy for Carpel Tunnel Syndrome Industrial- welding, cutting Industrial- welding, cutting

104 Light Basics Light travels in waves. Light travels in waves. The electromagnetic spectrum is divided into sections based on wavelength. The electromagnetic spectrum is divided into sections based on wavelength.

105 What makes laser light different than conventional light? Laser light has several unique qualities: 1. Monochromatic 2. Directional 3. Coherent But what do these mean?

106 Monochromatic Light Monochromatic light is light consisting of one wavelength only. Monochromatic light is light consisting of one wavelength only. Monochromatic Polychromatic

107 Directional Light Directional light has very low divergence. Directional light has very low divergence. Conventional light spreads in all directions, but laser light remains focused. Conventional light spreads in all directions, but laser light remains focused. Directional Non-Directional

108 Coherent Light Coherent light consists of waves that are in phase with each other. Coherent light consists of waves that are in phase with each other.

109 Lasing Material Lasers contain a medium which is used to cause the monochromatic effect. There are several states of lasing medium Lasers contain a medium which is used to cause the monochromatic effect. There are several states of lasing medium Solid State- Crystal injected dopant Solid State- Crystal injected dopant Semiconductor- Diode laser Semiconductor- Diode laser Liquid- dye laser Liquid- dye laser Gas- C02 laser Gas- C02 laser

110 Laser Construction Lasing Medium (gas, liquid, solid, semiconductor) Lasing Medium (gas, liquid, solid, semiconductor) Excitation Mechanism (power supply, flash lamp, laser) Excitation Mechanism (power supply, flash lamp, laser) Feedback Mechanism (mirrors) Feedback Mechanism (mirrors) Output coupler (semi-transparent mirror) Output coupler (semi-transparent mirror)

111 Laser Construction (cont)

112

113 Laser Use Research Research Study of mechanisms at interfaces Study of mechanisms at interfaces Detection of single molecules Detection of single molecules Medical/Dental Medical/Dental Eye surgery Eye surgery

114 Laser Use (cont) Commercial Commercial Supermarket checkout scanners Supermarket checkout scanners Determining site boundaries for construction Determining site boundaries for construction Industrial Industrial Cutting Cutting Welding Welding

115 Laser Hazard Classification ANSI Z Standard Class 1 (Exempt) Class 1 (Exempt) Incapable of producing damaging radiation levels Incapable of producing damaging radiation levels Class 2 (Low power) Class 2 (Low power) Eye protection is an aversion response Eye protection is an aversion response Visible ( nm) Visible ( nm) CW upper limit is 1mW CW upper limit is 1mW

116 Laser Hazard Classification ANSI Z Standard (cont) Class 3 (Medium Power) Class 3 (Medium Power) Divided into subclasses, 3a and 3b Divided into subclasses, 3a and 3b Hazardous under direct or specular reflection Hazardous under direct or specular reflection Non-hazardous under diffuse reflection Non-hazardous under diffuse reflection Normally non fire hazard Normally non fire hazard CW upper limit 0.5 W CW upper limit 0.5 W

117 Laser Hazard Classification ANSI Z Standard (cont) Class 4 (High Power) Class 4 (High Power) Hazardous to eye and skin from direct viewing/contact, specular, and diffuse reflections Hazardous to eye and skin from direct viewing/contact, specular, and diffuse reflections Produce non-beam hazardous such as air contaminants Produce non-beam hazardous such as air contaminants Fire hazard Fire hazard

118 Bio-Effects Bio-Effects Primary sites of damage Primary sites of damage eyes eyes skin skin Laser beam damage can be Laser beam damage can be thermal (heat) thermal (heat) acoustic acoustic photochemical photochemical

119 Eye Bio-Effects Three different ways for eye exposure Three different ways for eye exposure Retina (visible and Retina (visible and IR-A) IR-A) Cornea (UV-B, Cornea (UV-B, UV-C, IR-C) UV-C, IR-C) Lens (UV-A) Lens (UV-A)

120 Eye Bio-Effects (cont) Visible ( nm) Possible damage to Retina

121 Eye Bio-Effects (cont) Near-ultraviolet ( nm) Possible damage to Cornea

122 Eye Bio-Effects (cont) IR ( nm) Possible damage to Lens

123 Skin Bio-Effects Skin Sensitivity Skin Sensitivity Dermis (IR-A) Dermis (IR-A) Epidermis (UV-B, UV- C) Epidermis (UV-B, UV- C)

124 How Often Do Accidents Occur?

125 General Laser Safety Wear appropriate protective eyewear Wear appropriate protective eyewear Use minimum power/energy required for project Use minimum power/energy required for project Reduce laser output with shutters/attenuators, if possible Reduce laser output with shutters/attenuators, if possible Terminate laser beam with beam trap Terminate laser beam with beam trap Use diffuse reflective screens, remote viewing systems, etc., during alignments, if possible Use diffuse reflective screens, remote viewing systems, etc., during alignments, if possible Remove unnecessary objects from vicinity of laser Remove unnecessary objects from vicinity of laser Keep beam path away from eye level (sitting or standing) Keep beam path away from eye level (sitting or standing)

126 Non-Beam Hazards Chemical Chemical Chemical used in dye lasers can be known carcinogens or toxic also maybe difficult to dispose Chemical used in dye lasers can be known carcinogens or toxic also maybe difficult to dispose Optical Optical Plasma radiation can be produced. Similar to welders flash Plasma radiation can be produced. Similar to welders flash Fire Fire Class 3b and 4 lasers with high power outputs can cause fires Class 3b and 4 lasers with high power outputs can cause fires Electrical Electrical Most common, very high incident in maintenance Most common, very high incident in maintenance

127 Engineering Control Measures Beam housings Beam housings Activation Warning System Activation Warning System Shutters Shutters Beam Stop or Attenuator Beam Stop or Attenuator Remote firing controls Remote firing controls Interlocks Interlocks

128 Administrative Control Measures Warning signs/labels Warning signs/labels SOPs SOPs Training Training Optical Paths Covered Optical Paths Covered Class 2 and 3a Lasers Class 3b and 4 Lasers Warning Logo Information Label

129 PPE Control Measures Gloves Gloves Be wary of neck ties. Be wary of neck ties. Special clothing Special clothing Eyewear must be for the appropriate laser wavelength, attenuate the beam to safe levels.

130 Emergency Procedure Shut down the laser system Shut down the laser system Provide for the safety of the personnel, I.e. first aid, CPR, etc. Provide for the safety of the personnel, I.e. first aid, CPR, etc. If necessary, contact the fire department If necessary, contact the fire department Inform the Radiation Safety Division Inform the Radiation Safety Division Inform the Principal Investigator Inform the Principal Investigator DO NOT RESUME USE OF THE LASER SYSTEM WITHOUT APPROVAL OF THE LASER SAFETY OFFFICER

131 Irradiance E = Irradiance = W/cm2 E = Irradiance = W/cm2 Ф = total radiation power W Ф = total radiation power W A = area A = area a = beam diameter a = beam diameter r = viewing distance r = viewing distance Θ = beam divergence Θ = beam divergence

132 Beam diameter D = a + r Θ D = a + r Θ a = beam diameter a = beam diameter r = viewing distance r = viewing distance Θ = beam divergence Θ = beam divergence

133 Optical Density Log (incident power / transmitted power) Log (incident power / transmitted power) OD = log (total H / TLV) OD = log (total H / TLV)

134


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