Title: Code of Practice for users of personal dosimeters 1, 2

Transcription

1 Occupational Health and Environment Division Title: Code of Practice for users of personal dosimeters 1, 2 Number: en, version 2; English version 1 Date created: Date last modified: (English version: ) 1. Introduction This regulations document is intended for employees who have been registered as exposed worker 3 by the (Stralingsbeschermingseenheid: SBE). The provision and the use of personal dosimeters are subject to legal requirements. 2. Why personal dosimetry? Measurements and calculations made to determine the radiation exposure of individual persons is called personal dosimetry. Personal dosimetry is carried out for the following reasons: To determine the relationship between the radiological procedures and the associated radiation exposure to people. To test the effectiveness of the radiation protection measures. Dosimetry results can be used in optimising the protective measures and the working conditions. To identify trends. To verify that the current annual dose limits are not exceeded. To estimate the individual radiation exposure during radiological incidents and accidents. 3. What does a personal dosimeter look like? Front Back Inside The personal dosimeter is provided as a complete device (see photos). The supplier of personal dosimeters, Philips, provides every exposed worker with two uniquely coded personal dosimeters. For one period you will receive a dosimeter with a red coloured bar (see photo front ) and for the next period you will receive a dosimeter with a blue coloured bar. There is a label on the dosimeter that specifies for which period the dosimeter is intended (see photo back ). At the end of that period, the entire dosimeter device is replaced. 1 This regulations document is part of the Radiation Protection Regulation Erasmus MC. In case of discrepancies, the Dutch version of this regulations document prevails over the English version. 2 Specific conditions of the written internal authorisation prevail over this regulations document. 3 For definitions and terminology refer to 1/9

2 4. When will you receive a personal dosimeter? You will receive a dosimeter after you have been given permission 4 to carry out radiological procedures that will last for more than three months, and if you are assigned to category A or B. If you are to perform radiological procedures for less than three months, the local radiation protection officer will - prior to you starting -estimate the effective dose you could receive during the procedure. Should this estimate warrant a personal dosimeter, you will as yet receive a personal dosimeter or a direct reading dosimeter. 5. Code of practice for the use of the personal dosimeter Because the dosimeter is person-related and the dosimeter results are registered in the National Dose Registration and Information System (NDRIS), your dosimeter may not be worn by other persons. The name and numbers on the dosimeter must remain legible. Always use the clip to attach it. Do not open the case. The measurements will become unreliable after prolonged exposure (several hours) of the detectors to visible light. Should the case suddenly open, as the result of falling, for example, you can close it and continue to use it as normal. The detector card fits in the case only in one way. If the detectors are exposed to visible light for more than 4 hours, contact the SBE. The personal dosimeter is used to estimate the effective dose. In order to be able to make an adequate estimate, the following rules apply on where to wear the dosimeter: If you do not wear a lead apron: Attach the dosimeter at the front of your body at stomach or chest level. If you do wear a lead apron: Attach the dosimeter above the lead apron at chest level or on your collar (this is the preferred position). A thyroid collar may not cover the dosimeter. If the procedures and/or the work clothing give cause to this, the supervising radiation protection officer can consent to the dosimeter being worn on the shoulder. You should then choose for the shoulder closest to the radiation source. Make sure that the dosimeter is not covered by the lead apron or the thyroid collar as no dose information will then be obtained for unprotected body parts. For people wearing protective clothing, a dose correction factor can be used. The SBE can give you further information on this. Special procedures If your procedures give cause to this, your dosimeter can be worn elsewhere. You may only do this with permission of the SBE. In certain cases, it can be necessary or considered appropriate to estimate the dose of parts of the body. If ascertaining the dose distribution is important, additional personal dosimeters and/or extremity dosimeters are provided. As the purpose of the personal dosimeter is to be able to make an estimate of the occupational effective dose, it is important that you store the dosimeter in a place with a normal background radiation level outside your working hours. Some departments have a designated place for storing dosimeters, for example, in the coffee break area. For departments where this is not the case, consult the local radiation protection officer for the most appropriate storage place. If you lose a dosimeter, report this to the SBE as soon as possible. Another dosimeter can then potentially be temporarily provided. All dosimeters found must be handed in to the SBE as soon as possible. 4 The procedure is drawn up in the radiation protection regulations document: Admission to radiological procedures and occupational exposure 2/9

3 Note For dosimeters that have been lost or returned too late (after the 9 th ), extra costs will be charged to your department. Your department may pass these charges on to you. The dosimeter is used for a measurement period of one month. Dosimeters are supplied to the department around the 28th of the month. Once the new dosimeters have been delivered to your department, you will exchange your dosimeter as soon as possible but in any case before the 9 th of the next month. Your supervising radiation protection officer will inform you where to hand in your old dosimeter. If you expect to be absent during the exchange period (see schedule below), you will hand in your dosimeter to your supervising radiation protection officer or your dosimeter contact person before your absence. If, due to unforeseen circumstances, you are unable to exchange the dosimeter on time, contact your supervising radiation protection officer or your dosimeter contact person as soon as possible. Schedule for exchange of the personal dosimeters 28 th 9 th 28 th 9 th 28 th 9 th 28 th 9 th Explanation period to wear blue dosimeter period to wear red dosimeter exchange period 3/9

4 6. Results and registration of the personal dosimetry The dose measurement results can be found in the web-based dosimetry database of Philips 5. Once you have been given permission to be present at the requested radiological procedures, you will receive an from Philips with your username and password (see Appendix 1). You can use that information to log in to the Philips dosimetry database and see your own dose measurement results. In Appendix 2 you will find a manual. Although you will be able to log in immediately after having received the from Philips, your dose measurement results can only be viewed after the first reading of the personal dosimeter has been made. The dose measurement results are registered in the NDRIS and stored for at least 30 years after termination of your radiological procedures. The measurement results indicate the radiation exposure received during occupational external exposure. The dose measurement results of the personal dosimeter do not provide any viable information on the committed effective dose from internal contamination. For each measurement result of 1 msv or more per month, the SBE will send you, your supervising radiation protection officer and your dosimeter contact person a message, unless otherwise agreed upon with the supervising radiation protection officer. If the personal dosimeter entered a radiation field while you were not wearing the personal dosimeter, you must report this to the SBE as soon as possible. The dosimeter will then be evaluated separately. Only if the dose of your personal dosimeter definitely differs strongly from your real effective dose, your dose registered by NDRIS can be corrected by the Health and Safety Inspectorate (Arbeidsinspectie). To this end, you will need to make a written statement. If your occupational effective dose is greater than 20 msv in one calendar year, the SBE will report this to you, your supervising radiation protection officer, the radiation physician and the Health and Safety Inspectorate. December 2010 Dr. P.J.H. Kicken, Radiation Protection Expert Erasmus MC 5 The registration of the data in the dosimetry database of Philips complies with the Personal Data Protection Act and is registered under number P /9

5 Appendix 1: Sample from Philips 6. Code of Practice for users of personal dosimeters Subject: Philips Dosimetry service: admission to radiological procedures Dear Mr/Mrs XXXXXXXXX, On behalf of the of Erasmus MC we would like to inform you about the following: You have been given permission by the supervising radiation protection officer and SBE/Erasmus MC to carry out radiological procedures with the SBE work code: XXXXXXX If you have been classified in category A or B, you will have been provided with a dosimetry subscription. Philips will send you your personal dosimeter as soon as possible. You may start your radiological procedures after you have received your personal dosimeter. The (instructions on how to wear) your personal dosimeter can be found on the SBE website. We would also like to inform you that: The username and password given below will give you access to your details, as registered by the Philips Dosimetry service. A concise manual can be found on the SBE/Erasmus MC website. Your username is: username Your password is: password For questions, please contact SBE/Erasmus MC on tel: or sbe@erasmusmc.nl. Yours sincerely, Philips Radiation Protection Service/Dosimetry service Website: Note: The instructions on how to wear your personal dosimeter as stated on the Philips website have been incorporated in this radiation protection regulations document. 6 Date Appendix 1: Comment: This appendix may be modified without resulting in a change in version number of this radiation protection regulations document. 5/9

6 Appendix 2: A concise user manual for the Philips dosimetry system 7. Title: Manual Concise user manual for the Philips dosimetry system Number: A&Msh11001en Date created: Version1 Date last modified: Introduction This concise manual describes how you can access your dose measurement results, as recorded in the Philips dosimetry system 2. Logging in After having clicked the login button (inloggen), the following screen will appear: 7 Date Appendix 2: Comment: This appendix may be modified without resulting in a change in version number of this radiation protection regulations document. 6/9

7 Please enter the username and password that you received from Philips. Your username is composed of the first three letters of your name at birth, your date of birth and your first initial with a serial number. The username of A. Jansen born on would be JAN900101A1 or if there is more than one A. Jansen, it would be JAN900101A2. You may change your password if you so wish so after having logged in for the first time. If you enter the wrong password three times, access to the system will be blocked for security reasons. The blocked system can only be reset by Philips. Should you have forgotten your password, you can apply for a new password by clicking on the button forgotten your password (wachtwoord vergeten). This will be sent to your address. NOTE: the password is case sensitive. After logging in, you will see the message you are logged in to the dosimetry portal, in the bottom lefthand corner. Below this you will find additional information (for example, radiation worker). 7/9

8 You can view your dosimetry results by clicking he buttons overview dosimetry (overzicht dosimetrie), person (persoon) and exposure data of one person (stralingsgegevens van één persoon). NOTE: The period requested relates to the dosimeter reading date and relates to the radiation exposure in the previous period in which the dosimeter was worn. 8/9

9 You can specify the period for which you wish to see the dose results. You can view this overview as a PDF or Excel file. Below is an example of an Excel file. Dosimeter: This number indicates which of the two dosimeters was read. Reading date: Date on which the reading of the dosimeter (dose determination) was made. Gross dose: Measurement results, before correction for background radiation and dark current. Net dose: Measurement results, corrected for background radiation (1.8 µsv per day) and for dark current. The dark current is determined separately for each dosimeter. str. code: Indicates the category in which you have been classified (A, B or C) WI: This code (workplace indicator) indicates the type of work you perform (this code is linked to the SBE work code). NRG date: The date on which the dose measurement results were sent to NDRIS. 9/9