Radiation protection measurements in clinical practice - Dosimetry with NaCl pellets
(2019) MSFT01 20191Medical Physics Programme
- Abstract
- Within the field of medical radiation protection, radiation safety and personal dosimetry, there
is a constant pursuit for improving existing methods and evaluating new approaches for
measuring and quantifying the radiation doses that hospital staff may be exposed to in their
clinical work. There are numerous ways of determining what doses the staff are being exposed
to and the most commonly used is based on thermoluminescent dosemeters (TLD) with e.g.
chips of lithium fluoride. However, these traditional TLDs tend to be expensive which limit the
possibilities of having many simultaneous measuring points on the same occasions in clinical
practice. Furthermore, the TLDs based on lithium fluoride are toxic and have a limited lifetime,... (More) - Within the field of medical radiation protection, radiation safety and personal dosimetry, there
is a constant pursuit for improving existing methods and evaluating new approaches for
measuring and quantifying the radiation doses that hospital staff may be exposed to in their
clinical work. There are numerous ways of determining what doses the staff are being exposed
to and the most commonly used is based on thermoluminescent dosemeters (TLD) with e.g.
chips of lithium fluoride. However, these traditional TLDs tend to be expensive which limit the
possibilities of having many simultaneous measuring points on the same occasions in clinical
practice. Furthermore, the TLDs based on lithium fluoride are toxic and have a limited lifetime,
both physically and in terms of calibration.
Ordinary sodium chloride (NaCl) has, in many studies, been found to possess good properties
for quantifying exposure to ionizing radiation, making it a good candidate as a potential
dosemeter in clinical applications. NaCl is cheap, non-toxic and the use of NaCl for dosimetry
is based on one-time usage of the dosemeters with an individual calibration directly after
reading the signal. These factors in combination with the read out of the signal is based on
optical stimulation rather than thermal, provides for potentially high accuracy in the dose
determinations as well as lower detection limits.
The aims of this study have been to investigate the potential of ordinary household salt, in the
form of NaCl pellets, for radiation dose assessments in a variety of clinical applications: to
determine “hand doses”, “body doses” and to perform dose mapping of laboratory premises. In
the study it was also evaluated what advantages and disadvantages salt pellets has as a potential
dosemeter within these clinical applications as well as investigating which what type of
packaging technique that are beneficial in order to keep the NaCl pellets protected and easy to
handle, and what possible improvements that might be needed.
The project has shown that a good packaging technique, sufficient to keep the NaCl pellets
protected from both light exposure and mechanical stress during use in clinical work, is
necessary. An initial layer of ordinary household plastic followed by 4 layers of aluminum foil
was determined to be optimal. The study further showed that the equivalent dose to the treating
physicians hand surface, during low-dose-rate (LDR) brachytherapy, was between 0-0.33 mSv
using 96 measuring points evenly distributed over the hands. It also showed that the nurse,
during the same treatment and with the same amount of measuring points, received between 0-
0.27 mSv over the hand surface. Furthermore, using the NaCl pellets it was shown that the
equivalent dose to the hand surface, of the staff working with 18F-FDG synthetization, was
between 1.04-15.10 mSv for a 30-minutes session. The staff working with Ammonia
synthetization received a dose to the hand surface between 0.9-5.2 mGy per preparation. All
measurements of hand surface doses thus showed a large diversity in terms of dose magnitude
and how the dose is distributed over the hands. Also, the premises where 18F-FDG and
Ammonia synthetization takes place, were measured for 7 days and showed large variation in
the room depending on where the “sources” were placed and handled during the measurement
period. In addition, prolonged measurements were performed during 6 weeks at office premises
close to patient administration rooms (18F-FDG), which showed a mean dose rate of 0.032 uSv/h
i.e. well under the normal background level of 0.16 uSv/h. All together, these results show
potential for optimization of the various clinical practices and may be used when educating the
personal for planning and conducting their work. The NaCl pellet results also opens for more
elaborate assessments in other routine and complex clinical irradiation geometries. ‘ (Less) - Popular Abstract (Swedish)
- Persondosimetri för vårdpersonal, som i sitt yrke exponeras för joniserande strålning, är
ständigt ett hett ämne och under konstant utveckling. Stråldosen mäts och registreras för att
uppfylla riktlinjer och lagar, som syftar till att hålla personal säkra vid arbete med joniserande
strålning. Det finns en rad olika sätt att mäta stråldoser till en människa. För att effektivt
uppskatta och mäta strålningsexponering är arbetstagare inom vården utrustade med så kallade
dosimetrar, vilka kan placeras på olika delar av kroppen. En ny och lovande sådan dosimeter är
baserad på vanligt hushållssalt (NaCl). Denna dosimeter kan komma att bli ett effektivt,
lätthanterligt och billigt alternativ till de kommersiella dosimetrar som används på... (More) - Persondosimetri för vårdpersonal, som i sitt yrke exponeras för joniserande strålning, är
ständigt ett hett ämne och under konstant utveckling. Stråldosen mäts och registreras för att
uppfylla riktlinjer och lagar, som syftar till att hålla personal säkra vid arbete med joniserande
strålning. Det finns en rad olika sätt att mäta stråldoser till en människa. För att effektivt
uppskatta och mäta strålningsexponering är arbetstagare inom vården utrustade med så kallade
dosimetrar, vilka kan placeras på olika delar av kroppen. En ny och lovande sådan dosimeter är
baserad på vanligt hushållssalt (NaCl). Denna dosimeter kan komma att bli ett effektivt,
lätthanterligt och billigt alternativ till de kommersiella dosimetrar som används på sjukhusen
idag.
I detta MSc arbete har dessa saltbaserade dosimetrar undersökts för dosimetri inom olika
kliniska applikationer, och i de fall där det varit möjligt har resultaten jämförts med en etablerad
metod för dosimetri som används inom sjukvården idag. Bl.a. har dosimetrarna utvärderats för
användning på händer hos personal inom brachyterapi och radiofarmakaproduktion samt för
bakgrundsmätningar i vissa utvalda lokaler. Vanligt hushållssalt i lös form har pressats samman
till pellets, och en dedicerad förpackningsmetod för dessa har tagits fram. De inpackade
pelletsen placerades i sin tur på strategiska positioner på operationshandskar. Dessa handskar
har sedan använts i klinisk verksamhet av personal vid hantering av radioaktiva preparat vid
Skåne Universitetssjukhus. Saltpellets placerades även på strategiska platser i och nära lokaler
där radioaktiva läkemedel produceras, administreras till patienter eller handskas på annat vis.
Resultaten i detta MSc arbete visar att vanligt hushållssalt har bra egenskaper för att uppskatta
stråldoser, både till personal och i arbetsmiljö, samt möjliggör dosuppskattningar i många
mätpunkter samtidigt utan någon extra kostnad mer än i tid. Dosuppskattningar till många
punkter på händerna ger goda indikationer på hur personalen arbetar och rör sina händer i
strålfälten, vilket kan fungera som ett bra verktyg för att optimera det dagliga arbetet för att
minska doserna samt ett mer rättvist mätvärde än exempelvis mätvärdet från en
persondosimeter fäst på bröstet. Även långtidsmätningar i lokaler ger en bra fingervisning om
hur och var personalen kan röra sig i lokalerna för att minska doserna ytterligare. Därmed visar
detta på potentiella möjligheter för saltpellets att användas som dosimeter i kliniska
tillämpningar. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/8995828
- author
- Wilke, Petter
- supervisor
- organization
- course
- MSFT01 20191
- year
- 2019
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 8995828
- date added to LUP
- 2019-09-27 09:06:11
- date last changed
- 2019-09-27 16:18:57
@misc{8995828,
abstract = {{Within the field of medical radiation protection, radiation safety and personal dosimetry, there
is a constant pursuit for improving existing methods and evaluating new approaches for
measuring and quantifying the radiation doses that hospital staff may be exposed to in their
clinical work. There are numerous ways of determining what doses the staff are being exposed
to and the most commonly used is based on thermoluminescent dosemeters (TLD) with e.g.
chips of lithium fluoride. However, these traditional TLDs tend to be expensive which limit the
possibilities of having many simultaneous measuring points on the same occasions in clinical
practice. Furthermore, the TLDs based on lithium fluoride are toxic and have a limited lifetime,
both physically and in terms of calibration.
Ordinary sodium chloride (NaCl) has, in many studies, been found to possess good properties
for quantifying exposure to ionizing radiation, making it a good candidate as a potential
dosemeter in clinical applications. NaCl is cheap, non-toxic and the use of NaCl for dosimetry
is based on one-time usage of the dosemeters with an individual calibration directly after
reading the signal. These factors in combination with the read out of the signal is based on
optical stimulation rather than thermal, provides for potentially high accuracy in the dose
determinations as well as lower detection limits.
The aims of this study have been to investigate the potential of ordinary household salt, in the
form of NaCl pellets, for radiation dose assessments in a variety of clinical applications: to
determine “hand doses”, “body doses” and to perform dose mapping of laboratory premises. In
the study it was also evaluated what advantages and disadvantages salt pellets has as a potential
dosemeter within these clinical applications as well as investigating which what type of
packaging technique that are beneficial in order to keep the NaCl pellets protected and easy to
handle, and what possible improvements that might be needed.
The project has shown that a good packaging technique, sufficient to keep the NaCl pellets
protected from both light exposure and mechanical stress during use in clinical work, is
necessary. An initial layer of ordinary household plastic followed by 4 layers of aluminum foil
was determined to be optimal. The study further showed that the equivalent dose to the treating
physicians hand surface, during low-dose-rate (LDR) brachytherapy, was between 0-0.33 mSv
using 96 measuring points evenly distributed over the hands. It also showed that the nurse,
during the same treatment and with the same amount of measuring points, received between 0-
0.27 mSv over the hand surface. Furthermore, using the NaCl pellets it was shown that the
equivalent dose to the hand surface, of the staff working with 18F-FDG synthetization, was
between 1.04-15.10 mSv for a 30-minutes session. The staff working with Ammonia
synthetization received a dose to the hand surface between 0.9-5.2 mGy per preparation. All
measurements of hand surface doses thus showed a large diversity in terms of dose magnitude
and how the dose is distributed over the hands. Also, the premises where 18F-FDG and
Ammonia synthetization takes place, were measured for 7 days and showed large variation in
the room depending on where the “sources” were placed and handled during the measurement
period. In addition, prolonged measurements were performed during 6 weeks at office premises
close to patient administration rooms (18F-FDG), which showed a mean dose rate of 0.032 uSv/h
i.e. well under the normal background level of 0.16 uSv/h. All together, these results show
potential for optimization of the various clinical practices and may be used when educating the
personal for planning and conducting their work. The NaCl pellet results also opens for more
elaborate assessments in other routine and complex clinical irradiation geometries. ‘}},
author = {{Wilke, Petter}},
language = {{eng}},
note = {{Student Paper}},
title = {{Radiation protection measurements in clinical practice - Dosimetry with NaCl pellets}},
year = {{2019}},
}