Radiation Protection vid 2

Why is radiation protection important?

• x-rays or X radiation caused biologic changes in living cells and adversely affects all living tissues

• Many of the early pioneers and Dental radiography suffered from the adverse effects of radiation

• They have lost their fingers limbs and ultimately lives to excessive doses of radiation

• The hazards of radiation are now well documented, and radiation protection measures can be used to minimize radiation exposure for both the dental patient and the Dental radiographer.

In the present world now that the hazardous effects of radiation has been documented

It is important that radiation safety measures are applied in the dentist And the patient as well

When the human body is exposed to radiation It results in

Stochastic effect

Stochastic effect occurs due to

• Stochastic effect occurs due to a result of interaction of x-rays with the DNA chromosome which results in genetic mutation leading to cancer, tumors, and other diseases like leukemia

• It occurs as a direct function of dose

• The probability of occurrence increases with increasing absorbed dose

• They do not have a dose threshold.

• The severity of effects does not depend on the magnitude of the absorbed dose

Deterministic effect occurs due to

• The deterministic effect occurs due to significant cell damage or cell death leading to obvious functional impairment of tissue or organ

• Occurs due to significant cell death or cell injury

• Some examples are skin erythema Loss of hair, cataract formation, decreased fertility, radiation, sickness, teratogenesis, and fetal death

Determine occurs only after a

• it occurs only after a threshold of exposure has been exceeded

• The severity of the effect increases with increase in magnitude of the absorbed dose [ The severity of the effect is going to be dependent on the magnitude of the absorbed dose

• Because of an identifiable threshold level, appropriate radiation protection, mechanisms and occupational exposure dose limits can be implied hence reduce the likelihood of these effects occurring

Who requires radiation protection?

Patient dentist and people

When can you apply safety radiation measures

Before during and after

Prescribing dental images

• limiting the amount of X radiation received by a dental patient by proper prescribing or ordering of Dental images

• The dentist is the professional judgment to make decisions about the number type and frequency of Dental images

• Every patient dental condition is different and consequently, every patient should be evaluated for Dental images on an individual basis

• Examination should never include a predetermined number of images, nor should images be exposed at predetermined time intervals

Property equipment filtration

• Long wavelengths equals low energy equals more harmful to the patient equals less diagnostic

• Short wavelengths equals high energy equals less harmful to the patient and equals more diagnostic

• It is very important that you check the Machines Or the equipment dental filtration

• Filtration - part of the x-ray machine it is used to remove the long wavelength x-ray

• x-ray beam consist of different wavelength of radiation waves

• the long wavelength have low energy and they are going to be more harmful to the patient and contribute to less diagnostic information

• short wavelength x-rays are having higher energy and they have more diagnostic information and they are comparatively harmful to the patient

your filter removes the long wavelength x-rays and allows one leader short wavelength x-rays to pass through it

• your equipment should ideally consist of 1.5 mm thickness of aluminum filter for a machine which is less than <70 kg voltage

• 2.5 mm thickness of aluminum filter for more than >70 kg voltage equipment

• These are the guidelines for The thickness of filtration

Collimator

• The lead plate with the hole in the middle, which is used to restrict the size and shape of the x-ray beam and to reduce patient exposure

• There are circular collimator and rectangular collimator

• Rectangular collimator Most effective in reducing patient exposure

• Circular collimator Has excess radiation causing excessive patient exposure

Position indicating device PID

• An extension of the x-ray to head which is used to direct the x-ray bean

• Long 16 inch PID has less radiation of x-rays

• 8 inch PID is more divergent Leads to more radiation exposure

• Also comes in rectangular and circular, and also is more effective in rectangular

What are the measures to be taken during exposure?

• Lead apron and thyroid collar

• Lead apron - flexible, shield placed over the patient’s chest and lap to protect the reproductive and blood forming tissue from scatter radiation (Radiosensitive tissues)

• Thyroid collar Lead - Flexible, lead shield placed securely around the patient’s neck to protect the thyroid gland from scatter radiation (Radiosensitive tissues)

Image receptor (film) (during exposure measure)

• F speed film 20% reduction over E speed film

Beam alignment device (rinn kit) (during exposure measure)

• it helps to stabilize the receptor in the mouth and reduces the chances of movement

Proper technique vs improper technique

• proper technique will give you a proper diagnostic image

• Improper technique will give you a non-diagnostic image which results in exposure or retake

Proper exposure factors

• Kilovoltage setting of 60-80 kv

• Milliamperage setting of 6-8 mA

• Shortest exposure time possible

• All of these results in a good diagnostic image

What is after the exposure?

• proper receptor handling and proper film processing/image retrieval

• improper handling and improper processing can lead to artifacts which results in non-diagnostic image which results in a re-exposure or retake

Operator protection

• radiation protection guidelines

  • Distance and position recommendations

  • Shielding recommendations

• Radiation monitoring

  • Equipment monitoring

  • Personnel Monitoring

Distance and position recommendation

• radiographer should either leave the room or take a position behind a suitable barrier or wall during exposures

• The Dental radiographer must stand at least 6 feet away Or 2 meters from the x-ray tube head during x-ray exposure

• When maintaining the distance is not possible a protective barrier must be used

• The Dental radiographer must never hold a receptor in place for a patient or stabilize the x-ray tube head

Shielding recommendations

• protective barriers that absorb the primary beam can be incorporated into the office design - protecting the operator from primary and scatter radiation

• Dental offices, incorporate, adequate shielding, and walls through the use of several thicknesses of common construction material such as drywall

• A Leaded glass window or the use of a mirror is beneficial to monitor the patient during exposure

Equipment monitoring

• dental x-ray machines must be monitored for leakage radiation

• Leakage radiation is any radiation that is emitted from the X-ray tube head to head with the apart from the primary beam exception of the primary beam

• If the Dental x-ray tube head has a faulty tube head seal, leakage radiation results

• Dental x-ray equipment can be monitored for leakage radiation using a device that can be obtained through the state health department or from the manufacturers of Dental X-ray equipment

• It is important that you monitor machines Constantly for leakage radiation preventing radiation exposure unnecessarily

Personnel monitoring

• The amount of radiation that reaches the body of the Dental radiographer can be measured through the use of a personnel monitoring device

• The device is a thermoluminescent dosimeter

thermoluminescent dosimeter

• consists of a piece of thermoluminescent crystalline material inside a radiolucent package

• thermoluminescent Crystal exposed to ionizing radiation it absorbs and trapped some of the energy of the radiation and it’s Crystal lattice

• When the heated Crystal releases trapped energy in the form of visible light, the energy released is ionizing radiation

• A specialized detector measures the intensity of emitted light which is used to calculate dose of ionizing radiation that the Crystal was exposed to

• The dose measurement is used to calculate absorbed dose absorbed by the body

Dosimeter

• contains three filters - Three discs

• Dysprosium doped calcium sulfate

• To be worn over the chest under the lead apron over the normal clothing

• Can measure 100 micro SV to 10 SV

Radiation exposure guidelines

• National council on radiation protection and measurement says the maximum permissible dose

• The maximum dose equivalent that a body is permitted to receive within a specific period of time

• Dose of radiation that the body can endure with little or no injury

What is the maximum permissible dose for an occupationally exposed person

• 50 mSV per year 0.05 Sv/yr

• For a non-occupationally exposed person the general public 1 mSV per year

ALARA

• The ALARA is as low as reasonably achievable concept states that all exposure to radiation must be kept to a minimum

• To protect both patients and operators, every possible method of reducing exposure to radiation should be employed to minimize risk

• The radiation protection measures available can be used to minimize patient and operator exposure thus keeping radiation exposure as low as reasonably achievable