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Investigation of radiation protection of medical staff performing medical diagnostic examinations by using PET/CT technique
This content has been downloaded from IOPscience. Please scroll down to see the full text. 2015 J. Radiol. Prot. 35 197 (http://iopscience.iop.org/0952-4746/35/1/197) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 149.150.51.237 This content was downloaded on 07/04/2015 at 04:27
Please note that terms and conditions apply.
Society for Radiological Protection J. Radiol. Prot. 35 (2015) 197–207
Journal of Radiological Protection doi:10.1088/0952-4746/35/1/197
Investigation of radiation protection of medical staff performing medical diagnostic examinations by using PET/CT technique Małgorzata Wrzesień1 and Katarzyna Napolska2 1
Department of Nuclear Physics and Radiation Safety, Faculty of Physics and Applied Informatics, University of Lodz, Pomorska 149/153, 90-236 Lodz, Poland 2 Medical Diagnostic Centre VOXEL, PET/CT Laboratory, Polnocna 42, 91-425 Lodz, Poland E-mail: [email protected] Received 14 August 2014, revised 17 December 2014 Accepted for publication 5 January 2015 Published 3 February 2015 Abstract
Positron emission tomography (PET) is now one of the most important methods in the diagnosis of cancer diseases. Due to the rapid growth of PET/CT centres in Poland in less than a decade, radiation protection and, consequently, the assessment of worker exposure to ionising radiation, emitted mainly by the isotope 18F, have become essential issues. The main aim of the study was to analyse the doses received by workers employed in the Medical Diagnostic Centre. The analysis comprises a physicist, three nurses, three physicians, three technicians, as well as two administrative staff employees. High-sensitivity thermoluminescent detectors (TLDs) were used to measure the doses for medical staff. The personnel was classified into categories, among them employees having direct contact with the ‘source of radiation’— 18 FDG. The TLDs were placed on the fingertips of both hands and they were also attached at the level of eye lenses, thyroid and gonads depending on the assigned category. The highest dose of radiation was observed during the administration of the 18FDG to the patients. In the case of the physicist, the highest dose was recorded during preparation of the radiopharmaceutical— 18 FDG. The body parts most exposed to ionizing radiation are the fingertips of the thumb, index and middle finger. Keywords: nuclear medicine, radiation protection, hand exposure, ionizing radiation, PET/CT (Some figures may appear in colour only in the online journal) 0952-4746/15/010197+11$33.00 © 2015 IOP Publishing Ltd Printed in the UK
197
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
1. Introduction The dose limit for workers exposed to ionizing radiation is 20 mSv yr−1, the source of this limitation are recommendations of the International Commission on Radiological Protection in Publication 103 (ICRP 2007) and the Council Directive No 96/29/EURATOM (EURATOM 1996), still in force. These employees are included in the system of monitoring of individual exposure to radiation (Piwowarska-Bilska et al 2010). The average annual doses received by workers in the nuclear medicine who work with open sources of radiation can be relatively high compared to other professional groups, also working under exposure to ionizing radiation (Al-Haj and Lagarde 2002, Croft and Lefuare 2002, Martins et al 2007, Valuckas et al 2007, Velasques de Oliveira et al 2007, Wrzesień and Olszewski 2008, 2012). Therefore, such workers in particular must be inspected for occupational risk of exposure, and the effectiveness of this control measure should be analysed. Monitoring of the occupational exposure to ionizing radiation is usually performed using personal dosimeters. The effective dose measured in this way seems to be much lower than the limit currently in force of 20 mSv yr−1. At the same time, the equivalent dose to the hands (e.g. measured by ring dosimeter) may exceed the annual limit of 500 mSv. Exposure of the hands of workers (who prepare and dispense radiopharmaceuticals) in nuclear medicine facilities is a complex problem and dose distribution is subject to many variables, and often it is not clear which parts of the hand are the most exposed. The dose limit for the skin is specified as the equivalent dose, (in mSv), averaged over any area of 1 cm2, regardless of the area exposed and, therefore, point doses should be measured at various locations on the hand. The personnel of the medical facilities performing positron emission tomography (PET) diagnostic procedures are exposed to ionizing radiation from the most commonly used isotope, 18F, used in combination with deoxyglucose marker (18FDG). PET is now one of the most important methods in the diagnosis of cancer diseases (Królicki et al 2011). Its importance is related to technological progress (the introduction of hybrid camera PET/CT, PET/MR) and to the use of radiopharmaceuticals for measuring the number of tumour phenotypes. PET examinations are currently being used in the preliminary diagnosis, assessment of tumour stage, monitoring of treatment, as well as prognosis. There are currently 14 PET/CT centres in operation in Poland, equipped with 16 cameras. There are plans to open new facilities—in Lublin, Cracow (two centres), and in Katowice (Królicki et al 2012). Due to the rapid growth of PET/CT centres in Poland in less than a decade, radiation protection and, consequently, the assessment of worker exposure to ionising radiation, emitted mainly by the isotope 18F, is an urgent necessity. 2. Materials and methods High-sensitivity thermoluminescent detectors (TLDs) made of lithium fluoride (LiF: Mg, Cu, P—MCP—produced by the Polish company Niewiadomski and Co.) were used to determine the doses. Absorption characteristic of the detectors is comparable with that of the human soft tissues; these detectors are characterised by high reproducibility of the results and long dose memory. The detectors can be used to measure the doses ranging from 2 µSv to 10 Sv (Niewiadomski et al 1996, Waligórski et al 1999). The TLDs are small (4.5 mm dia., 0.9 mm thick) and reusable. A gamma radiation source—137Cs (60Co/137Cs irradiator) was used to calibrate the detectors in Secondary Standards Laboratory. Dosemeters were calibrated in accordance with ISO 4037-3 (International Standard 1999) in the range from 0.05 to 30 mGy as the air kerma. The Hp(0.07) for fingers, and Hp(10) was calculated taking into account 198
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
Figure 1. Location of TLDs on physicist’s hand (TLDs under an adhesive tape).
the conversion coefficient hpK(0.07), hpK(10) respectively, given in the ISO International Standard. The conversion coefficient Hp(3) was obtained by approximation coefficients Hp(3,0°)/K in the range of photon energies ranging from 0.01 to 0.9 MeV, as specified by Vanhavere et al (EURADOS 2012). We used the slab (ISO 1999), rod phantoms (ISO 2000) and also the cylinder with a diameter of 20 cm (ISO 2000). The readings of the dosimeters were read out using an RA 94 reader from Mikrolab Co. The TLDs used were subjected to a typical process of annealing in a thermoluminescent detector (TLD) oven produced by PTW and could be used in subsequent measurements. Measurements were performed during routine activities of the personnel in Medical Diagnostic Centre (MDC) in Lodz provided with PET/CT unit. The personnel was classified into categories, including employees having direct contact with the source of radiation—18FDG—physicist and nurses (Group I), physicians and staff performing diagnostic examinations (Group II) and other personnel (Group III). Personnel exposure measurements performed using TLDs included the following steps: • For employees of Group I, determinations of exposure of the hands from dose values recorded by the thermoluminescent (TL) detectors placed on the fingertips of the thumb, index, middle, ring and little fingers of the right and left hand (see figure 1). In addition, measurements were carried out to assess the doses received by eye lenses, thyroid and gonads; in that case the TLDs were attached at the level of eye lenses, thyroid (figure 2) and gonads (figure 3). • For employees classified as Group II and Group III, measurements were carried out by TL detectors places at the level of eye lenses, thyroid and gonads. The employees of the MDC include one physicist, three nurses, three physicians, three technicians who perform diagnostic examinations, and two secretaries (one of whom has contact with the patients who leave the diagnostic centre). The study included all employed staff. All workers were right-handed. The detectors used to assess the doses received by the hands of physicist and nurses were also used to measure the doses to the eye lenses; they were placed in a transparent foil and then affixed at the proper place by an adhesive tape, as shown in figure 2. The ‘gonadal’ TLDs were placed in a special pendant (see figure 3) which was worn by the workers on the level of gonads. To measure the doses on the level of thyroid, the TLDs were placed in a transparent foil and affixed (by an adhesive tape) to the special hoop which was worn by workers on the neck. The laboratory where the measurements were performed does not produce 18FDG, the radiopharmaceutical was received by the MDC from Germany (now from Cracow). 199
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
Figure 2. TLDs used to measure the doses on the level of eye lenses and hoop dosimeter
with TLDs (3 pcs) used to measure the doses on the level of thyroid.
Figure 3. TLDs placed in the ‘gonadal’ dosimeter.
3. Results The basic data on table 1.
18
FDG activity and the number of diagnosed patients are summarized in
3.1. Assessment of the hand exposure of physicist
Operations performed by the physicist related to the handling of open source radiation— 18 FGD includes delivering the ‘source’ (i.e. the vial with 18FDG) to the chamber (where the activity of radiopharmaceutical is automatically dispensed), removing the syringe after the automatic filling process, and putting it into a container made of tungsten. Dose measurements were carried out for specified tasks using TLDs placed on the fingertips of both hands of the employee. The main aim of this part of measurements was to verify that the manipulations, carried out by a physicist as part of work with a source of radiation, contribute the most to the dose received by fingertips of his hands. Figure 4 presents the values of doses recorded by TLDs placed on fingertips on the left and right hand of the physicist, during delivering the vial with 18FDG to the dispenser chamber. 200
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
Table 1. The basic data on 18FDG activity and the number of diagnosed patients.
Characterised quantity
Value
Total activity of 18FDG prepared for patients during one working day (GBq) Total activity of 18FDG delivered to MDC (GBq) Mean activity of 18FDG injected to the patients (MBq) Total number of patients examined during six measurement days Mean number of patients examined during one working day
2.16 4.83 191.85 62 10
0.20 mean 75th percentile median
0.15
25th percentile max
Hp(0.07) [mSv]
min
0.10
0.05
0.00 thumb RH index RH middle RH ring RH
little RH thumb LH index LH middle LH ring LH
little LH
Location of the measuring points Figure 4. Values of doses recorded by TLDs placed on fingertips on the left and right hand of the physicist when delivering the vial with 18FDG to the dispenser chamber (RH—right hand, LH—left hand).
The highest doses were registered by the TL detectors placed on the tips of the index, thumb and the middle finger of the left hand. The mean Hp(0.07) and standard deviation are as follows: 0.060 ± 0.066 mSv, 0.049 ± 0.040 mSv and 0.040 ± 0.048 mSv, respectively. The mean values of doses per 18F activity to all measurements points of physicist’s right and left hand during the preparation of radiopharmaceutical are shown in figure 5. During the preparation of the radiopharmaceutical, the syringe is shielded with tungsten and the whole process of dispensing the activity of 18FDG is carried out automatically. The most exposed to ionizing radiation are the fingertips of the index, thumb and middle fingers of the dominant (right) hand. Value of recorded doses per unit activity of 18FDG are as follows: 0.20 ± 0.06 µSv MBq−1, 0.11 ± 0.07 µSv MBq−1 and 0.05 ± 0.02 µSv MBq−1, respectively. The mean values of doses recorded by TL detectors placed on the five fingertips of the left hand and fingertip of the little finger of the right hand of physicist’s who performed two 201
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
mean
3.0E-4
75th percentile median 25th percentile max min
D/A [mSv/MBq]
2.0E-4
1.0E-4
0.0 thumb RH
index RH
middle RH
ring RH
little RH
thumb LH
index LH
middle LH
ring LH
little LH
Location of measuring points
Figure 5. Values of doses per
18
F activity to all measurement points of physicist’s right and left hand during the preparation of radiopharmaceutical (RH—right hand, LH—left hand).
procedures—delivering the vial with 18FDG and preparation of radiopharmaceutical, during one working day are equal within the range of error value. 3.2. Assessment of the hand exposure of nurses
The mean values (+SEM) of doses per 18FDG activity recorded by TLDs placed on the fingertips of the left and right hand of nurses during the administration of the radiopharmaceutical to the patients are presented in figures 6(a) and (b), respectively. All employed nurses are right-handed. Figures 6(a) and also 6(b) show significant differences in the level of exposure of the hands in this professional group. There is a strong upward trend in the exposure of the left hand, in particular the fingertips of the thumb, index and middle fingers. The most exposed to ionizing radiation in the case of nurse 1 is the fingertip of middle finger (dose recorded in this point is over four times higher compared to doses recorded at the same point for nurses 2 and 3), ring finger of the right hand and also the thumb of the left hand. 3.3. Exposure of the eyes, thyroid and gonads of the physicist (during dispensing of 18FDG activity) and nurses on the basis of the dose recorded by TLDs placed at the level of eye lenses, thyroid and gonads
The TLDs located at the level of eye lens of the physicist registered an average dose equal to 2.82 ± 0.35 µSv MBq−1 when dispensing the 18FDG activity. The average doses recorded 202
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
8.0E-4
(a)
nurse 1 nurse 2 nurse 3
7.0E-4
Hp(0.07)/A [mSv/MBq]
6.0E-4
5.0E-4
4.0E-4
3.0E-4
2.0E-4
1.0E-4
0.0 thumb
index finger
middle finger
ring finger
little finger
Location of the measuring points on the nurse's right hand
(b)
nurse 1 nurse 2 nurse 3
8.0E-4
Hp(0.07)/A [mSv/MBq]
6.0E-4
4.0E-4
2.0E-4
0.0 thumb
index finger
middle finger
ring finger
little finger
Location of the measuring pionts on the nurse's left hand
Figure 6. (a) Mean doses (+SEM) recorded by TLDs placed on nurses’ fingertips of the right hand per 1 GBq of
18 F activity administered to the patient in the form of 18FDG. (b) Mean doses (+SEM) recorded by TLDs placed on nurses’ fingertips of the left hand per 1 GBq of 18F activity administered to the patient in the form of 18FDG.
203
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
by the TLDs placed at the level of the right and left eye lens are not statistically different (Cochran–Cox test p
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My IOPscience
Investigation of radiation protection of medical staff performing medical diagnostic examinations by using PET/CT technique
This content has been downloaded from IOPscience. Please scroll down to see the full text. 2015 J. Radiol. Prot. 35 197 (http://iopscience.iop.org/0952-4746/35/1/197) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 149.150.51.237 This content was downloaded on 07/04/2015 at 04:27
Please note that terms and conditions apply.
Society for Radiological Protection J. Radiol. Prot. 35 (2015) 197–207
Journal of Radiological Protection doi:10.1088/0952-4746/35/1/197
Investigation of radiation protection of medical staff performing medical diagnostic examinations by using PET/CT technique Małgorzata Wrzesień1 and Katarzyna Napolska2 1
Department of Nuclear Physics and Radiation Safety, Faculty of Physics and Applied Informatics, University of Lodz, Pomorska 149/153, 90-236 Lodz, Poland 2 Medical Diagnostic Centre VOXEL, PET/CT Laboratory, Polnocna 42, 91-425 Lodz, Poland E-mail: [email protected] Received 14 August 2014, revised 17 December 2014 Accepted for publication 5 January 2015 Published 3 February 2015 Abstract
Positron emission tomography (PET) is now one of the most important methods in the diagnosis of cancer diseases. Due to the rapid growth of PET/CT centres in Poland in less than a decade, radiation protection and, consequently, the assessment of worker exposure to ionising radiation, emitted mainly by the isotope 18F, have become essential issues. The main aim of the study was to analyse the doses received by workers employed in the Medical Diagnostic Centre. The analysis comprises a physicist, three nurses, three physicians, three technicians, as well as two administrative staff employees. High-sensitivity thermoluminescent detectors (TLDs) were used to measure the doses for medical staff. The personnel was classified into categories, among them employees having direct contact with the ‘source of radiation’— 18 FDG. The TLDs were placed on the fingertips of both hands and they were also attached at the level of eye lenses, thyroid and gonads depending on the assigned category. The highest dose of radiation was observed during the administration of the 18FDG to the patients. In the case of the physicist, the highest dose was recorded during preparation of the radiopharmaceutical— 18 FDG. The body parts most exposed to ionizing radiation are the fingertips of the thumb, index and middle finger. Keywords: nuclear medicine, radiation protection, hand exposure, ionizing radiation, PET/CT (Some figures may appear in colour only in the online journal) 0952-4746/15/010197+11$33.00 © 2015 IOP Publishing Ltd Printed in the UK
197
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
1. Introduction The dose limit for workers exposed to ionizing radiation is 20 mSv yr−1, the source of this limitation are recommendations of the International Commission on Radiological Protection in Publication 103 (ICRP 2007) and the Council Directive No 96/29/EURATOM (EURATOM 1996), still in force. These employees are included in the system of monitoring of individual exposure to radiation (Piwowarska-Bilska et al 2010). The average annual doses received by workers in the nuclear medicine who work with open sources of radiation can be relatively high compared to other professional groups, also working under exposure to ionizing radiation (Al-Haj and Lagarde 2002, Croft and Lefuare 2002, Martins et al 2007, Valuckas et al 2007, Velasques de Oliveira et al 2007, Wrzesień and Olszewski 2008, 2012). Therefore, such workers in particular must be inspected for occupational risk of exposure, and the effectiveness of this control measure should be analysed. Monitoring of the occupational exposure to ionizing radiation is usually performed using personal dosimeters. The effective dose measured in this way seems to be much lower than the limit currently in force of 20 mSv yr−1. At the same time, the equivalent dose to the hands (e.g. measured by ring dosimeter) may exceed the annual limit of 500 mSv. Exposure of the hands of workers (who prepare and dispense radiopharmaceuticals) in nuclear medicine facilities is a complex problem and dose distribution is subject to many variables, and often it is not clear which parts of the hand are the most exposed. The dose limit for the skin is specified as the equivalent dose, (in mSv), averaged over any area of 1 cm2, regardless of the area exposed and, therefore, point doses should be measured at various locations on the hand. The personnel of the medical facilities performing positron emission tomography (PET) diagnostic procedures are exposed to ionizing radiation from the most commonly used isotope, 18F, used in combination with deoxyglucose marker (18FDG). PET is now one of the most important methods in the diagnosis of cancer diseases (Królicki et al 2011). Its importance is related to technological progress (the introduction of hybrid camera PET/CT, PET/MR) and to the use of radiopharmaceuticals for measuring the number of tumour phenotypes. PET examinations are currently being used in the preliminary diagnosis, assessment of tumour stage, monitoring of treatment, as well as prognosis. There are currently 14 PET/CT centres in operation in Poland, equipped with 16 cameras. There are plans to open new facilities—in Lublin, Cracow (two centres), and in Katowice (Królicki et al 2012). Due to the rapid growth of PET/CT centres in Poland in less than a decade, radiation protection and, consequently, the assessment of worker exposure to ionising radiation, emitted mainly by the isotope 18F, is an urgent necessity. 2. Materials and methods High-sensitivity thermoluminescent detectors (TLDs) made of lithium fluoride (LiF: Mg, Cu, P—MCP—produced by the Polish company Niewiadomski and Co.) were used to determine the doses. Absorption characteristic of the detectors is comparable with that of the human soft tissues; these detectors are characterised by high reproducibility of the results and long dose memory. The detectors can be used to measure the doses ranging from 2 µSv to 10 Sv (Niewiadomski et al 1996, Waligórski et al 1999). The TLDs are small (4.5 mm dia., 0.9 mm thick) and reusable. A gamma radiation source—137Cs (60Co/137Cs irradiator) was used to calibrate the detectors in Secondary Standards Laboratory. Dosemeters were calibrated in accordance with ISO 4037-3 (International Standard 1999) in the range from 0.05 to 30 mGy as the air kerma. The Hp(0.07) for fingers, and Hp(10) was calculated taking into account 198
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
Figure 1. Location of TLDs on physicist’s hand (TLDs under an adhesive tape).
the conversion coefficient hpK(0.07), hpK(10) respectively, given in the ISO International Standard. The conversion coefficient Hp(3) was obtained by approximation coefficients Hp(3,0°)/K in the range of photon energies ranging from 0.01 to 0.9 MeV, as specified by Vanhavere et al (EURADOS 2012). We used the slab (ISO 1999), rod phantoms (ISO 2000) and also the cylinder with a diameter of 20 cm (ISO 2000). The readings of the dosimeters were read out using an RA 94 reader from Mikrolab Co. The TLDs used were subjected to a typical process of annealing in a thermoluminescent detector (TLD) oven produced by PTW and could be used in subsequent measurements. Measurements were performed during routine activities of the personnel in Medical Diagnostic Centre (MDC) in Lodz provided with PET/CT unit. The personnel was classified into categories, including employees having direct contact with the source of radiation—18FDG—physicist and nurses (Group I), physicians and staff performing diagnostic examinations (Group II) and other personnel (Group III). Personnel exposure measurements performed using TLDs included the following steps: • For employees of Group I, determinations of exposure of the hands from dose values recorded by the thermoluminescent (TL) detectors placed on the fingertips of the thumb, index, middle, ring and little fingers of the right and left hand (see figure 1). In addition, measurements were carried out to assess the doses received by eye lenses, thyroid and gonads; in that case the TLDs were attached at the level of eye lenses, thyroid (figure 2) and gonads (figure 3). • For employees classified as Group II and Group III, measurements were carried out by TL detectors places at the level of eye lenses, thyroid and gonads. The employees of the MDC include one physicist, three nurses, three physicians, three technicians who perform diagnostic examinations, and two secretaries (one of whom has contact with the patients who leave the diagnostic centre). The study included all employed staff. All workers were right-handed. The detectors used to assess the doses received by the hands of physicist and nurses were also used to measure the doses to the eye lenses; they were placed in a transparent foil and then affixed at the proper place by an adhesive tape, as shown in figure 2. The ‘gonadal’ TLDs were placed in a special pendant (see figure 3) which was worn by the workers on the level of gonads. To measure the doses on the level of thyroid, the TLDs were placed in a transparent foil and affixed (by an adhesive tape) to the special hoop which was worn by workers on the neck. The laboratory where the measurements were performed does not produce 18FDG, the radiopharmaceutical was received by the MDC from Germany (now from Cracow). 199
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
Figure 2. TLDs used to measure the doses on the level of eye lenses and hoop dosimeter
with TLDs (3 pcs) used to measure the doses on the level of thyroid.
Figure 3. TLDs placed in the ‘gonadal’ dosimeter.
3. Results The basic data on table 1.
18
FDG activity and the number of diagnosed patients are summarized in
3.1. Assessment of the hand exposure of physicist
Operations performed by the physicist related to the handling of open source radiation— 18 FGD includes delivering the ‘source’ (i.e. the vial with 18FDG) to the chamber (where the activity of radiopharmaceutical is automatically dispensed), removing the syringe after the automatic filling process, and putting it into a container made of tungsten. Dose measurements were carried out for specified tasks using TLDs placed on the fingertips of both hands of the employee. The main aim of this part of measurements was to verify that the manipulations, carried out by a physicist as part of work with a source of radiation, contribute the most to the dose received by fingertips of his hands. Figure 4 presents the values of doses recorded by TLDs placed on fingertips on the left and right hand of the physicist, during delivering the vial with 18FDG to the dispenser chamber. 200
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
Table 1. The basic data on 18FDG activity and the number of diagnosed patients.
Characterised quantity
Value
Total activity of 18FDG prepared for patients during one working day (GBq) Total activity of 18FDG delivered to MDC (GBq) Mean activity of 18FDG injected to the patients (MBq) Total number of patients examined during six measurement days Mean number of patients examined during one working day
2.16 4.83 191.85 62 10
0.20 mean 75th percentile median
0.15
25th percentile max
Hp(0.07) [mSv]
min
0.10
0.05
0.00 thumb RH index RH middle RH ring RH
little RH thumb LH index LH middle LH ring LH
little LH
Location of the measuring points Figure 4. Values of doses recorded by TLDs placed on fingertips on the left and right hand of the physicist when delivering the vial with 18FDG to the dispenser chamber (RH—right hand, LH—left hand).
The highest doses were registered by the TL detectors placed on the tips of the index, thumb and the middle finger of the left hand. The mean Hp(0.07) and standard deviation are as follows: 0.060 ± 0.066 mSv, 0.049 ± 0.040 mSv and 0.040 ± 0.048 mSv, respectively. The mean values of doses per 18F activity to all measurements points of physicist’s right and left hand during the preparation of radiopharmaceutical are shown in figure 5. During the preparation of the radiopharmaceutical, the syringe is shielded with tungsten and the whole process of dispensing the activity of 18FDG is carried out automatically. The most exposed to ionizing radiation are the fingertips of the index, thumb and middle fingers of the dominant (right) hand. Value of recorded doses per unit activity of 18FDG are as follows: 0.20 ± 0.06 µSv MBq−1, 0.11 ± 0.07 µSv MBq−1 and 0.05 ± 0.02 µSv MBq−1, respectively. The mean values of doses recorded by TL detectors placed on the five fingertips of the left hand and fingertip of the little finger of the right hand of physicist’s who performed two 201
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
mean
3.0E-4
75th percentile median 25th percentile max min
D/A [mSv/MBq]
2.0E-4
1.0E-4
0.0 thumb RH
index RH
middle RH
ring RH
little RH
thumb LH
index LH
middle LH
ring LH
little LH
Location of measuring points
Figure 5. Values of doses per
18
F activity to all measurement points of physicist’s right and left hand during the preparation of radiopharmaceutical (RH—right hand, LH—left hand).
procedures—delivering the vial with 18FDG and preparation of radiopharmaceutical, during one working day are equal within the range of error value. 3.2. Assessment of the hand exposure of nurses
The mean values (+SEM) of doses per 18FDG activity recorded by TLDs placed on the fingertips of the left and right hand of nurses during the administration of the radiopharmaceutical to the patients are presented in figures 6(a) and (b), respectively. All employed nurses are right-handed. Figures 6(a) and also 6(b) show significant differences in the level of exposure of the hands in this professional group. There is a strong upward trend in the exposure of the left hand, in particular the fingertips of the thumb, index and middle fingers. The most exposed to ionizing radiation in the case of nurse 1 is the fingertip of middle finger (dose recorded in this point is over four times higher compared to doses recorded at the same point for nurses 2 and 3), ring finger of the right hand and also the thumb of the left hand. 3.3. Exposure of the eyes, thyroid and gonads of the physicist (during dispensing of 18FDG activity) and nurses on the basis of the dose recorded by TLDs placed at the level of eye lenses, thyroid and gonads
The TLDs located at the level of eye lens of the physicist registered an average dose equal to 2.82 ± 0.35 µSv MBq−1 when dispensing the 18FDG activity. The average doses recorded 202
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
8.0E-4
(a)
nurse 1 nurse 2 nurse 3
7.0E-4
Hp(0.07)/A [mSv/MBq]
6.0E-4
5.0E-4
4.0E-4
3.0E-4
2.0E-4
1.0E-4
0.0 thumb
index finger
middle finger
ring finger
little finger
Location of the measuring points on the nurse's right hand
(b)
nurse 1 nurse 2 nurse 3
8.0E-4
Hp(0.07)/A [mSv/MBq]
6.0E-4
4.0E-4
2.0E-4
0.0 thumb
index finger
middle finger
ring finger
little finger
Location of the measuring pionts on the nurse's left hand
Figure 6. (a) Mean doses (+SEM) recorded by TLDs placed on nurses’ fingertips of the right hand per 1 GBq of
18 F activity administered to the patient in the form of 18FDG. (b) Mean doses (+SEM) recorded by TLDs placed on nurses’ fingertips of the left hand per 1 GBq of 18F activity administered to the patient in the form of 18FDG.
203
M Wrzesień and K Napolska
J. Radiol. Prot. 35 (2015) 197
by the TLDs placed at the level of the right and left eye lens are not statistically different (Cochran–Cox test p
