Part …: ( Add part number and title) Module…: ( Add module number and title) Lesson …: ( Add session number and title) Learning objectives: Upon completion of this lesson, the students will be able to: … . (Add a list of what the students are expected to learn or be able to do upon completion of the session) Activity: ( Add the method used for presenting or conducting the lesson – lecture, demonstration, exercise, laboratory exercise, case study, simulation, etc.) Duration: ( Add presentation time or duration of the session – hrs) Materials and equipment needed: (List materials and equipment needed to conduct the session, if appropriate) References: (List the references for the session)
RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY L13.2: Occupational exposure - Radioprotection measures IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology
Individual monitoring and exposure assessment (III)
Evaluation of dose is an important aspect of radiation protection
It is important that workers return dosimeters on time for processing
Delays in the evaluation of a dosimeter can result in the loss of the stored information
Licensees should make every effort to recover any missing dosimeters
Individual monitoring when a lead apron is used (I)
The dosimeter should be worn under the apron for estimating the effective dose
The other body areas not protected by the apron will receive higher dose
One dosimeter worn under the apron will yield a reasonable estimate of effective dose for most instances
In case of high workload (interventional radiology) an additional dosimeter outside the apron should be considered by the RPO
Individual monitoring when a lead apron is used (II)
When expected doses are high , two dosimeters are required:
1 under the apron at waist level
1 over the apron at collar level
The effective dose E is given by:
E = 0.5 Hw + 0.025 Hn
Hw : dose at waist level under the apron
Hn : dose recorded by a dosimeter worn at neck level over the apron
Note : The thyroid shielding allows 50% reduction of the E
The dosimeter worn over the apron at collar level gives also an estimation of thyroid and eye lens doses
Individual monitoring and exposure assessment (IV)
In some facilities and for some individuals with a low level of exposure (e.g.: general dental practitioners), area dosimetry to estimate the level of dose per procedure can be an acceptable alternative .
Some X Ray systems for dental radiography, or others used in surgical theatres which use X Rays on a limited number of occasions a month may not require individual dosimetry for all staff involved although fluoroscopy in surgical theatres may lead to high dose in short time if not properly conducted
In these cases, area dosimetry or some other individual dose evaluation per procedure could allow the RPO to estimate the typical level of risk
Registrant and licensees shall develop programmes for monitoring of the workplace:
All survey meters used for workplace monitoring shall be calibrated and this calibration shall be traceable to a standards dosimetry laboratory
Initial monitoring should be conducted immediately after the installation of new radiology equipment and shall include measurements of radiation leakage from equipment, and area monitoring of useable space around radiology rooms
Employers, registrants and licensees shall, in consultation with workers or through their representatives, include in the local rules and procedures the values of any relevant investigation level, and the procedure to be followed in the event that any such value is exceeded.
any equipment failure, severe accident or error takes place, which causes, or has the potential to cause, a dose in excess of annual dose limit
any other event or unusual circumstance that causes, or has the potential to cause a dose in excess of the annual dose limits or the operational restrictions imposed on the installation (e.g., the significant change in workload or operating conditions of radiology equipment)
The investigation shall be initiated as soon as possible following discovery of the event, and a written report shall be prepared concerning its cause (determination or verification of any doses received, corrective actions, and instructions or recommendations to avoid recurrence)
The report shall be submitted to the Regulatory Authority and other concerned bodies as required, as soon as possible after the investigation, or as otherwise specified and kept for a specified period.
Part 13.2: Occupational exposure Topic 4: Health surveillance IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology
Under normal working conditions, the doses incurred in a radiology department are lower than the dose limits.
No specific radiation-related medical examinations are normally required for persons who are occupationally exposed to ionizing radiation, as there are no diagnostic tests which yield information relevant to exposures that are close to or below dose limits.
It is therefore rare for the radiation component of the working environment of a radiology department to significantly influence the decision about the fitness of a worker to undertake work with radiation or the influence the general conditions of service
However in the case of accidental exposure to high doses (of the order of magnitude of 0.2-0.5 Sv or higher), specific radiation-related medical investigation are necessary
Part 13.2: Occupational exposure Topic 5: Records IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology