| 1. |
- Andersson, Martin, et al.
(författare)
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A biokinetic and dosimetric model for ionic indium in humans
- 2017
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 62:16, s. 6397-6407
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Tidskriftsartikel (refereegranskat)abstract
- This paper reviews biokinetic data for ionic indium, and proposes a biokinetic model for systemic indium in adult humans. The development of parameter values focuses on human data and indium in the form of ionic indium(III), as indium chloride and indium arsenide. The model presented for systemic indium is defined by five different pools: plasma, bone marrow, liver, kidneys and other soft tissues. The model is based on two subsystems: one corresponding to indium bound to transferrin and one where indium is transported back to the plasma, binds to red blood cell transferrin and is then excreted through the kidneys to the urinary bladder. Absorbed doses to several organs and the effective dose are calculated for 111In- and 113mIn-ions. The proposed biokinetic model is compared with previously published biokinetic indium models published by the ICRP. The absorbed doses are calculated using the ICRP/ICRU adult reference phantoms and the effective dose is estimated according to ICRP Publication 103. The effective doses for 111In and 113mIn are 0.25 mSv MBq-1 and 0.013 mSv MBq-1 respectively. The updated biokinetic and dosimetric models presented in this paper take into account human data and new animal data, which represent more detailed and presumably more accurate dosimetric data than that underlying previous models for indium.
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| 2. |
- Andersson, Martin, et al.
(författare)
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An internal radiation dosimetry computer program, IDAC 2.0, for estimation of patient doses from radiopharmaceuticals
- 2014
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 162:3, s. 299-305
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Tidskriftsartikel (refereegranskat)abstract
- The internal dosimetry computer program internal dose assessment by computer (IDAC) for calculations of absorbed doses to organs and tissues as well as effective doses to patients from examinations with radiopharmaceuticals has been developed. The new version, IDAC2.0, incorporates the International Commission on Radiation Protection (ICRP)/ICRU computational adult male and female voxel phantoms and decay data from the ICRP publication 107. Instead of only 25 source and target regions, calculation can now be made with 63 source regions to 73 target regions. The major advantage of having the new phantom is that the calculations of the effective doses can be made with the latest tissue weighting factors of ICRP publication 103. IDAC2.0 uses the ICRP human alimentary tract (HAT) model for orally administrated activity and for excretion through the gastrointestinal tract and effective doses have been recalculated for radiopharmaceuticals that are orally administered. The results of the program are consistent with published data using the same specific absorption fractions and also compared with published data from the same computational phantoms but with segmentation of organs leading to another set of specific absorption fractions. The effective dose is recalculated for all the 34 radiopharmaceuticals that are administered orally and has been published by the ICRP. Using the new HAT model, new tissue weighting factors and the new adult computational voxel phantoms lead to an average effective dose of half of its earlier estimated value. The reduction mainly depends on electron transport simulations to walled organs and the transition from the stylised phantom with unrealistic interorgan distances to more realistic voxel phantoms.
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| 3. |
- Andersson, Martin, et al.
(författare)
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An upgrade of the internal dosimetry computer program IDAC
- 2012
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Ingår i: Medical Physics in the Baltic States. - : Kaunas University of Technology. - 1822-5721. ; , s. 120-123
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Konferensbidrag (refereegranskat)abstract
- A full update of the internal dosimetry computer program IDAC has been conducted. The new update is based on new and more accurate computational phantoms to calculate effective dose and absorbed dose to organs and tissues. The new ICRP Adult Reference Computational Phantoms has been adopted as well as the latest of the ICRP standardized biokinetic models. The updated computer program includes a user-friendly graphical user interface.
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| 4. |
- Andersson, Martin, et al.
(författare)
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Effective dose to adult patients from 338 radiopharmaceuticals estimated using ICRP biokinetic data, ICRP/ICRU computational reference phantoms and ICRP 2007 tissue weighting factors
- 2014
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Ingår i: EJNMMI Physics. - : Springer. - 2197-7364. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Effective dose represents the potential risk to a population of stochastic effects of ionizing radiation (mainly lethal cancer). In recent years, there have been a number of revisions and updates influencing the way to estimate the effective dose. The aim of this work was to recalculate the effective dose values for the 338 different radiopharmaceuticals previously published by the International Commission on Radiological Protection (ICRP).Method: The new estimations are based on information on the cumulated activities per unit administered activity in various organs and tissues and for the various radiopharmaceuticals obtained from the ICRP publications 53, 80 and 106. The effective dose for adults was calculated using the new ICRP/International Commission on Radiation Units (ICRU) reference voxel phantoms and decay data from the ICRP publication 107. The ICRP human alimentary tract model has also been applied at the recalculations. The effective dose was calculated using the new tissue weighting factors from ICRP publications 103 and the prior factors from ICRP publication 60. The results of the new calculations were compared with the effective dose values published by the ICRP, which were generated with the Medical Internal Radiation Dose (MIRD) adult phantom and the tissue weighting factors from ICRP publication 60.Results: For 79% of the radiopharmaceuticals, the new calculations gave a lower effective dose per unit administered activity than earlier estimated. As a mean for all radiopharmaceuticals, the effective dose was 25% lower. The use of the new adult computational voxel phantoms has a larger impact on the change of effective doses than the change to new tissue weighting factors.Conclusion: The use of the new computational voxel phantoms and the new weighting factors has generated new effective dose estimations. These are supposed to result in more realistic estimations of the radiation risk to a population undergoing nuclear medicine investigations than hitherto available values.
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| 5. |
- Andersson, Martin, et al.
(författare)
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Improved estimates of the radiation absorbed dose to the urinary bladder wall
- 2014
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Ingår i: Physics in Medicine and Biology. - : Institute of Physics Publishing (IOPP). - 0031-9155 .- 1361-6560. ; 59:9, s. 2173-2182
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Tidskriftsartikel (refereegranskat)abstract
- Specific absorbed fractions (SAFs) have been calculated as a function of the content in the urinary bladder in order to allow more realistic calculations of the absorbed dose to the bladder wall. The SAFs were calculated using the urinary bladder anatomy from the ICRP male and female adult reference computational phantoms. The urinary bladder and its content were approximated by a sphere with a wall of constant mass, where the thickness of the wall depended on the amount of urine in the bladder. SAFs were calculated for males and females with 17 different urinary bladder volumes from 10 to 800 mL, using the Monte Carlo computer program MCNP5, at 25 energies of mono-energetic photons and electrons ranging from 10 KeV to 10 MeV. The decay was assumed to be homogeneously distributed in the urinary bladder content and the urinary bladder wall, and the mean absorbed dose to the urinary bladder wall was calculated. The Monte Carlo simulations were validated against measurements made with thermoluminescent dosimeters. The SAFs obtained for a urine volume of 200 mL were compared to the values calculated for the urinary bladder wall using the adult reference computational phantoms. The mean absorbed dose to the urinary wall from F-18-FDG was found to be 77 mu Gy/MBq formales and 86 mu Gy/MBq for females, while for (99)mTc-DTPA the mean absorbed doses were 80 mu Gy/MBq for males and 86 mu Gy/MBq for females. Compared to calculations using a constant value of the SAF from the adult reference computational phantoms, the mean absorbed doses to the bladder wall were 60% higher for F-18-FDG and 30% higher for (99)mTc-DTPA using the new SAFs.
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| 6. |
- Andersson, Martin, et al.
(författare)
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ORGAN DOSES AND EFFECTIVE DOSE FOR FIVE PET RADIOPHARMACEUTICALS
- 2016
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 8-253
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Tidskriftsartikel (refereegranskat)abstract
- Diagnostic investigations with positron-emitting radiopharmaceuticals are dominated by (18)F-fluorodeoxyglucose ((18)F-FDG), but other radiopharmaceuticals are also commercially available or under development. Five of them, which are all clinically important, are (18)F-fluoride, (18)F-fluoroethyltyrosine ((18)F-FET), (18)F-deoxyfluorothymidine ((18)F-FLT), (18)F-fluorocholine ((18)F-choline) and (11)C-raclopride. To estimate the potential risk of stochastic effects (mainly lethal cancer) to a population, organ doses and effective dose values were updated for all five radiopharmaceuticals. Dose calculations were performed using the computer program IDAC2.0, which bases its calculations on the ICRP/ICRU adult reference voxel phantoms and the tissue weighting factors from ICRP publication 103. The biokinetic models were taken from ICRP publication 128. For organ doses, there are substantial changes. The only significant change in effective dose compared with previous estimations was a 46 % reduction for (18)F-fluoride. The estimated effective dose in mSv MBq(-1) was 1.5E-02 for (18)F-FET, 1.5E-02 for (18)F-FLT, 2.0E-02 for (18)F-choline, 9.0E-03 for (18)F-fluoride and 4.4E-03 for (11)C-raclopride.
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| 7. |
- Giussani, Augusto, et al.
(författare)
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A Compartmental Model for Biokinetics and Dosimetry of 18F-Choline in Prostate Cancer Patients
- 2012
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 2159-662X. ; 53:6, s. 985-993
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Tidskriftsartikel (refereegranskat)abstract
- PET with F-18-choline (F-18-FCH) is used in the diagnosis of prostate cancer and its recurrences. In this work, biodistribution data from a recent study conducted at Skane University Hospital Malmo were used for the development of a biokinetic and dosimetric model. Methods: The biodistribution of F-18-FCH was followed for 10 patients using PET up to 4 h after administration. Activity concentrations in blood and urine samples were also determined. A compartmental model structure was developed, and values of the model parameters were obtained for each single patient and for a reference patient using a population kinetic approach. Radiation doses to the organs were determined using computational (voxel) phantoms for the determination of the S factors. Results: The model structure consists of a central exchange compartment (blood), 2 compartments each for the liver and kidneys, 1 for spleen, 1 for urinary bladder, and 1 generic compartment accounting for the remaining material. The model can successfully describe the individual patients' data. The parameters showing the greatest interindividual variations are the blood volume (the clearance process is rapid, and early blood data are not available for several patients) and the transfer out from liver (the physical half-life of F-18 is too short to follow this long-term process with the necessary accuracy). The organs receiving the highest doses are the kidneys (reference patient, 0.079 mGy/MBq; individual values, 0.033-0.105 mGy/MBq) and the liver (reference patient, 0.062 mGy/MBq; individual values, 0.036-0.082 mGy/MBq). The dose to the urinary bladder wall of the reference patient varies between 0.017 and 0.030 mGy/MBq, depending on the assumptions on bladder voiding. Conclusion: The model gives a satisfactory description of the biodistribution of F-18-FCH and realistic estimates of the radiation dose received by the patients.
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| 8. |
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| 9. |
- Gunnarsson, Mikael, et al.
(författare)
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Long-term biokinetics and radiation exposure of patients undergoing 14C-glycocholic acid and 14C-xylose breath tests.
- 2007
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Ingår i: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 22:6, s. 762-771
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Tidskriftsartikel (refereegranskat)abstract
- The (14)C-glycocholic acid and (14)C-xylose breath tests are clinically used for the diagnosis of intestinal diseases, such as bacterial overgrowth in the small intestine. The two tests have in earlier studies been thoroughly evaluated regarding their clinical value, but due to the long physical half-life of (14)C and the limited biokinetic and dosimetric data, which are available for humans, several hospitals have been restrictive in their use. The aim of this study was to investigate the long-term biokinetics and dosimetry of the two (14)C compounds in patients and volunteers, using the highly sensitive accelerator mass spectrometry (AMS) technique. Eighteen (18) subjects were included, 9 for each compound. The (14)C content in samples from exhaled air, urine, and, for some subjects, also feces were analyzed with both liquid scintillation counting (LSC) and AMS. The results from the glycocholic acid study showed that, up to 1 year after the administration, 67%+/-6% (mean+/-standard deviation) of the administered activity was recovered in exhaled air, 2.4%+/-0.4% was found in urine, and 7.6% (1 subject) in feces. In the xylose study, the major part was found in the urine (66%+/-2%). A significant part was exhaled (28%+/-5%), and the result from an initial 72-hour stool collection from 2 of the subjects showed that the excretion by feces was insignificant. The absorbed dose to various organs and tissues and the effective dose were calculated by using biokinetic models, based on a combination of experimental data from the present study and from earlier reports. In the glycocholic acid study, the highest absorbed dose was received by the colon (1.2 mGy/MBq). In the xylose study, the adipose tissue received 0.8 mGy/MBq. The effective dose was estimated to 0.5 (glycocholic acid) and 0.07 mSv/MBq (xylose). Thus, from a radiation protection point of view, we see no need for restrictions in using the two (14)C-labeled radiopharmaceuticals on adults with the activities normally administered (0.07-0.4 MBq).
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| 10. |
- Gunnarsson, Mikael, et al.
(författare)
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No radiation protection reasons for restrictions on C-14 urea breath tests in children.
- 2002
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Ingår i: British Journal of Radiology. - : British Institute of Radiology. - 1748-880X .- 0007-1285. ; 75:900, s. 982-986
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Tidskriftsartikel (refereegranskat)abstract
- Traditional 14C urea breath tests are normally not used for younger children because the radiation exposure is unknown. High sensitivity accelerator mass spectrometry and an ultra-low amount (440 Bq) of 14C urea were therefore used both to diagnose Helicobacter pylori (HP) infection in seven children, aged 3–6 years, and to make radiation dose estimates. The activity used was 125 times lower than the amount normally used for older children and 250 times lower than that used for adults. Results were compared with previously reported biokinetic and dosimetric data for adults and older children aged 7–14 years. 14C activity concentrations in urine and exhaled air per unit administered activity for younger children (3–6 years) correspond well with those for older children (7–14 years). For a child aged 3–6 years who is HP negative, the urinary bladder wall receives the highest absorbed dose, 0.3 mGy MBq-1. The effective dose is 0.1 mSv MBq-1 for the 3-year-old child and 0.07 mSv MBq-1 for the 6-year-old child. For two children, the 10 min and 20 min post-14C administration samples of exhaled air showed a significantly higher amount of 14C activity than for the rest of the children, that is 6% and 19% of administered activity exhaled per hour compared with 0.3–0.9% (mean 0.5%) of administered activity exhaled per hour indicating that these two children that is were HP positive. For a 3-year-old HP positive child, absorbed dose to the urinary bladder wall was 0.3 mGy MBq-1 and effective dose per unit of administered activity was 0.4 mSv MBq-1. Using 55 kBq, which is a normal amount for older children when liquid scintillation counters are used for measurement, the effective dose will be approximately 6 µSv to a 3-year-old HP negative child and 20 µSv to a HP positive child. Thus there is no reason for restrictions on performing a normal 14C urea breath test, even on young children.
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| 11. |
- Johansson, L, et al.
(författare)
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Biokinetics of iodide in man: Refinement of current ICRP dosimetry models
- 2003
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Ingår i: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 18:3, s. 445-450
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Tidskriftsartikel (refereegranskat)abstract
- A compartmental model describing the distribution and retention of radioactive iodide in thyroid and other organs is presented. The model is developed from published ICRP models. It is designed primarily for radiation dosimetry of iodine radionuclides used in nuclear medicine, but may also be useful for occupational radiation protection. In the proposed model, the distribution of iodide to the thyroid is assumed to be more rapid than in earlier models. Uptakes in stomach wall and salivary glands are considered, and the absorbed doses to these organs calculated. The partitioning of iodide between stomach wall and content is also discussed. Recirculation of organic iodine is also taken into account. Age-dependent half-times for iodide in the thyroid, as well as for organically-bound iodine are presented. The proposed model is applicable for dose estimations with different uptakes in the thyroid as well as for the situation when the thyroid is blocked, completely or incompletely.
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| 12. |
- Kamp, A., et al.
(författare)
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A revised compartmental model for biokinetics and dosimetry of 2- F-18 FDG
- 2023
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Ingår i: EJNMMI Physics. - : Springer Science and Business Media LLC. - 2197-7364. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe aim was to review available biokinetic data, collect own experimental data, and propose an updated compartmental model for 2-[F-18]FDG in the frame of the revision of the ICRP report on dose coefficients for radiopharmaceuticals used in diagnostic nuclear medicine.MethodsThe compartmental model was developed based on published biokinetic data for 2-[F-18]FDG. Additional data on urinary excretion in 23 patients (11 males, 12 females) undergoing whole-body PET/CT examinations were obtained within this study. The unknown biokinetic model parameters were derived using the software SAAM II and verified with a modified version of IDAC-Iodide. Dose coefficients for reference adults were calculated with the programme IDAC-Dose 2.1. A dynamic bladder model was employed for urinary bladder dosimetry.ResultsThe proposed model consists of following compartments: blood, heart wall, brain, liver, lungs, pancreas, spleen, kidneys, urinary bladder content and a generic pool compartment "Other". The latter was introduced to account for 2-[F-18]FDG in body organ and tissues besides the explicitly modelled ones. The model predictions showed a good agreement with experimental data. Urinary bladder wall received the highest absorbed dose coefficient of 7.5E-02 mGy/MBq under the assumption of initial urine volume of 100 ml, first voiding at 45 min p.i. and 3.75 h voiding intervals thereafter. The effective dose coefficient calculated according to the current dosimetry framework of ICRP amounted to 1.7E-02 mSv/MBq, compared to 1.9E-02 mSv/MBq in ICRP Publication 128.ConclusionA compartmental model for 2-[F-18]FDG was proposed and will be used to replace the descriptive biokinetic model of ICRP Publication 128. The revised model and the provided dose coefficients are expected to improve reference dosimetry for patients administered with 2-[F-18]FDG.
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| 13. |
- Leide Svegborn, Sigrid, et al.
(författare)
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Excretion of radionuclides in human breast milk after nuclear medicine examinations. Biokinetic and dosimetric data and recommendations on breastfeeding interruption
- 2016
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 43:5, s. 808-821
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To review early recommendations and propose guidelines for breastfeeding interruption after administration of radiopharmaceuticals, based on additional biokinetic and dosimetric data. Methods Activity concentrations in breast milk from 53 breastfeeding patients were determined. The milk was collected at various times after administration of 16 different radiopharmaceuticals. The fraction of the activity administered to the mother excreted in the breast milk, the absorbed doses to various organs and tissues and the effective dose to the infant were estimated.Results The fraction of the administered activity excreted per millilitre of milk varied widely from 10(-10) to 10(-3) MBq/MBq administered. For Tc-99m-labelled radiopharmaceuticals, the total fraction of the administered activity excreted in the milk varied from 0.0057 % for Tc-99m-labelled red blood cells (RBC) to 19 % for Tc-99m-pertechnetate. The effective dose to an infant per unit activity administered to the mother ranged from 6.7 x 10(-6) mSv/MBq for Tc-99m-labelled RBC to 3.6 x 10(-2) mSv/MBq for Tc-99m-pertechnetate. For the other radiopharmaceuticals, the total fraction of administered activity excreted in the milk varied from 0.018 % (Cr-51-EDTA) to 48 % (I-131-NaI). The effective dose ranged from 5.6 x 10(-5) mSv(infant)/MBq(mother) (Cr-51-EDTA) to 106 mSv(infant)/MBq(mother) (I-131-NaI).Conclusions Based on an effective dose limit of 1 mSv to the infant and a typical administered activity, we recommend cessation of breastfeeding for I-131-NaI and interruption of feeding for 12 h for I-125-iodohippurate, I-131-iodohippurate, Tc-99m-pertechnetate and Tc-99m-MAA. During this 12-h period all breast milk should be expressed at least three times and discarded. For the other radiopharmaceuticals included in this study, no interruption of breastfeeding is necessary.
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| 14. |
- Leide Svegborn, Sigrid
(författare)
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External radiation exposure of personnel in nuclear medicine from F-18, Tc-99m and I-131 with special reference to fingers, eyes and thyroid
- 2012
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 149:2, s. 196-206
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Tidskriftsartikel (refereegranskat)abstract
- The radiation exposure of fingers, thyroid and eyes of workers handling radiopharmaceuticals during various nuclear medicine procedures was measured using thermoluminescent dosemeters. Dosemeters were placed on the finger tips of 19 workers on several different occasions for various procedures. Additionally, the routinely determined whole-body doses to various groups of workers were analysed. The finger dose measurements demonstrated clear differences between the various tasks, from 0.0012 µGy MBq(-1) (unpacking and installing (99)Mo/(99m)Tc-generator) to 3.0 µGy MBq(-1) (syringe withdrawal, injection and waste handling of (18)F-FDG). As long as the worker was handling (99m)Tc, the dose to the fingers was well below the ICRP dose limits, even when the activity was high. Special concern should, however, be devoted to the handling of (18)F, since the dose to the fingers could easily reach the dose limits. The estimated dose to eyes and thyroid was well below the dose limits. Since the introduction of the positron emission tomography/computed tomography facility, the annual whole-body dose has increased for those directly involved in the handling of (18)F. The annual whole-body dose of 0.2-2.5 mGy was, however, well below the dose limits.
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| 15. |
- Leide Svegborn, Sigrid
(författare)
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Radiation exposure of patients and personnel from a PET/CT procedure with F-18-FDG
- 2010
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 208-213
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Tidskriftsartikel (refereegranskat)abstract
- The positron emission tomography (PET)/computed tomography (CT) camera is a combination of a PET camera and a CT. The image from the PET camera is based on the detection of radiation that is emitted from a radioactive tracer, which has been given to the patient as an intravenous injection. The radiation that is emitted from the radioactive tracer is more energetic than any other radiation used in medical diagnostic procedures and this requires special radiation protection routines. The CT image is based on the detection of radiation produced from an X-ray tube and transmitted through the patient. The radiation exposure of the personnel during the CT procedure is generally very low. Regarding radiation exposure of the patient, it is important to notice whether a CT scan has been performed prior to the PET/CT in order to avoid any unnecessary irradiation. The total effective dose to the patient from a PET/CT procedure is approximately 10 mSv. The major part comes from internal irradiation due to radiopharmaceuticals within the patients (e.g. (18)F-FDG: approximately 6-7 mSv), and a minor part is due to the CT scan (low-dose CT scan: approximately 2-4 mSv). If a full diagnostic CT investigation is performed, the effective dose may be considerably higher. If the patient is pregnant, a PET/CT procedure should be avoided or postponed, unless it is vital for the patient. An interruption in breastfeeding is not necessary after a PET/CT procedure of the nursing mother. Close contact between the patient and a small child should however be avoided for a couple of hours after the administration of the radiopharmaceutical. The radiation dose to the personnel arises mainly due to handling of the radiopharmaceuticals (syringe withdrawal, injection, waste handling, etc.) and from close contact to the patient. This radiation dose can be limited by using the inverse-square law, i.e. by using the fact that the absorbed dose decreases substantially with increasing distance between the radiation source and the personnel.
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| 16. |
- Mattsson, Sören, et al.
(författare)
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Current activities in the ICRP concerning estimation of radiation doses to patients from radiopharmaceuticals for diagnostic use
- 2011
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 317, s. 012008-012008
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Konferensbidrag (refereegranskat)abstract
- A Task Group within the ICRP Committees 2 and 3 is continuously working to improve absorbed dose estimates to patients investigated with radiopharmaceuticals. The work deals with reviews of the literature, initiation of new or complementary studies of the biokinetics of a compound and dose estimates. Absorbed dose calculations for organs and tissues have up to now been carried out using the MIRD formalism. There is still a lack of necessary biokinetic data from measurements in humans. More time series obtained by nuclear medicine imaging techniques such as whole-body planar gamma-camera imaging, SPECT or PET are highly desirable for this purpose. In 2008, a new addendum to ICRP Publication 53 was published under the name of ICRP Publication 106 containing biokinetic data and absorbed dose information to organs and tissues of patients of various ages for radiopharmaceuticals in common use. That report also covers a number of generic models and realistic maximum models covering other large groups of substances (e.g. "(123)I-brain receptor substances"). Together with ICRP Publication 80, most radiopharmaceuticals in clinical use at the time of publication were covered except the radioiodine labeled compounds for which the ICRP dose estimates are still found in Publication 53. There is an increasing use of new radiopharmaceuticals, especially PET-tracers and the TG has recently finished its work with biokinetic and dosimetric data for (18)F-FET, (18)F-FLT and (18)F-choline. The work continues now with new data for (11)C-raclopride, (11)C-PiB and (123)I-ioflupan as well as re-evaluation of published data for (82)Rb-chloride, (18)F-fluoride and radioiodide. This paper summarises published ICRP-information on dose to patients from radiopharmaceuticals and gives some preliminary data for substances under review.
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| 17. |
- Mattsson, Sören, et al.
(författare)
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X-RAY AND MOLECULAR IMAGING DURING PREGNANCY AND BREASTFEEDING—WHEN SHOULD WE BE WORRIED?
- 2021
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 195:3-4, s. 339-348
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Tidskriftsartikel (refereegranskat)abstract
- Some of the ethically most sensitive issues in radiation protection arise at imaging of pregnant-and potentially pregnant-patients and of newborn. This article reviews the current literature and recommendations on imaging during pregnancy and breastfeeding. Risks related to alternative non-ionizing radiation methods are also considered. With few exceptions, exposure of the fetus through radiography, computed tomography (CT) and nuclear medicine imaging can be limited to safe levels, although studies such as abdominal-pelvic CT cannot avoid significant exposure to fetuses. Eight to 10 weeks post-conception, the fetus has a thyroid which starts to concentrate iodide having crossed the placenta barrier resulting in unacceptably high doses to the fetal thyroid after administration of 131I- and even 123I-iodide and other radiopharmaceuticals with a high content of free radioiodine. Many radiopharmaceuticals are excreted through breast milk. Breastfeeding interruption recommendations should be followed to keep the effective dose to the infant below 1 mSv.
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| 18. |
- Nosslin, Bertil, et al.
(författare)
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A generic model for C-11 labelled radiopharmaceuticals for imaging receptors in the human brain
- 2003
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Ingår i: Radiation Protection Dosimetry. - 1742-3406. ; 105:1-4, s. 587-591
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Tidskriftsartikel (refereegranskat)abstract
- A large number of rachopharmaceuticals labelled with C-11 (half-time 0.340 h) are being developed for positron emission tomographic studies of different types of receptor in the human brain. For most of these agents, the available biokinetic data are insufficient to construct realistic compound-specific biokinetic models for calculating the internal radiation dose delivered to persons undergoing investigation. A generic model for brain receptor substances that predicts the internal dose with sufficient accuracy for general radiation protection purposes has, therefore, been developed. Biokinetic data for 13 C-11-radiopharmaceuticals used clinically for imaging different brain receptors indicate that, despite differences in chemical structure. their uptake and retention in the human brain and other tissues are broadly similar. The proposed model assumes instantaneous deposition of 5% of the injected radioactivity in the brain, with the remaining radioactivity being rapidly and uniformly distributed throughout all other tissues. Elimination from all tissues is assumed to occur with a half-time of 2 h. It is further assumed that 75% of the injected C-11 is excreted in the urine, and 25% via the gall bladder, with a half-time of 2 h. This model yields all effective dose of 4.5 X 10(-3) mSv MBq(-1), with doses of 3.2 X 10(-2), 1.7 X 10(-2), 8.7 X 10(-3), 5.2 X 10(-3), and 3.8 X 10(-3) mGy MBq(-1) to the urinary bladder, gall bladder, kidneys, brain and ovaries, respectively. These closes are well within the range of those reported using compound-specific models for the radiopharmaceutals studied.
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| 19. |
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| 20. |
- Oddstig, Jenny, et al.
(författare)
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Comparison of conventional and Si-photomultiplier-based PET systems for image quality and diagnostic performance
- 2019
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Ingår i: BMC Medical Imaging. - : Springer Science and Business Media LLC. - 1471-2342. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A new generation of positron emission tomography with computed tomography (PET-CT) was recently introduced using silicon (Si) photomultiplier (PM)-based technology. Our aim was to compare the image quality and diagnostic performance of a SiPM-based PET-CT (Discovery MI; GE Healthcare, Milwaukee, WI, USA) with a time-of-flight PET-CT scanner with a conventional PM detector (Gemini TF; Philips Healthcare, Cleveland, OH, USA), including reconstruction algorithms per vendor's recommendations. METHODS: Imaging of the National Electrical Manufacturers Association IEC body phantom and 16 patients was carried out using 1.5 min/bed for the Discovery MI PET-CT and 2 min/bed for the Gemini TF PET-CT. Images were analysed for recovery coefficients for the phantom, signal-to-noise ratio in the liver, standardized uptake values (SUV) in lesions, number of lesions and metabolic TNM classifications in patients. RESULTS: In phantom, the correct (> 90%) activity level was measured for spheres ≥17 mm for Discovery MI, whereas the Gemini TF reached a correct measured activity level for the 37-mm sphere. In patient studies, metabolic TNM classification was worse using images obtained from the Discovery MI compared those obtained from the Gemini TF in 4 of 15 patients. A trend toward more malignant, inflammatory and unclear lesions was found using images acquired with the Discovery MI compared with the Gemini TF, but this was not statistically significant. Lesion-to-blood-pool SUV ratios were significantly higher in images from the Discovery MI compared with the Gemini TF for lesions smaller than 1 cm (p < 0.001), but this was not the case for larger lesions (p = 0.053). The signal-to-noise ratio in the liver was similar between platforms (p = 0.52). Also, shorter acquisition times were possible using the Discovery MI, with preserved signal-to-noise ratio in the liver. CONCLUSIONS: Image quality was better with Discovery MI compared to conventional Gemini TF. Although no gold standard was available, the results indicate that the new PET-CT generation will provide potentially better diagnostic performance.
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| 22. |
- Stenström, Kristina, et al.
(författare)
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Local variations in C-14 - How is bomb-pulse dating of human tissues and cells affected?
- 2010
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Ingår i: Nuclear Instruments & Methods In Physics Research Section B-Beam Interactions With Materials And Atoms. - : Elsevier BV. - 0168-583X. ; 268:7-8, s. 1299-1302
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Konferensbidrag (refereegranskat)abstract
- Atmospheric nuclear weapons testing in the late 1950s and early 1960s almost doubled the amount of C-14 in the atmosphere. The resulting C-14 "bomb-pulse" has been shown to provide useful age information in e.g. forensic and environmental sciences, biology and the geosciences. The technique is also currently being used for retrospective cell dating in man, in order to provide insight into the rate of formation of new cells in the human body. Bomb-pulse dating relies on precise measurements of the declining C-14 concentration in atmospheric CO2 collected at clean-air sites. However, it is not always recognized that the calculations can be complicated in some cases by significant local variations in the specific activity of C-14 in carbon in the air and foodstuff. This paper presents investigations of local C-14 variations in the vicinities of nuclear installations and laboratories using C-14. Levels of C-14 in workers using this radioisotope are also discussed. (C) 2009 Elsevier B.V. All rights reserved.
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| 23. |
- Stenström, Kristina, et al.
(författare)
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Low-level occupational 14C contamination – results from a pilot study
- 2008
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 130, s. 337-342
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a pilot study in which specific activities of (14)C in hair and urine from 11 radiation workers handling (14)C-containing substances have been measured using accelerator mass spectrometry. Varying degrees of contamination were revealed: up to 63% excess in hair and 400% excess in urine. Although the (14)C excess reported in this study would result in low effective doses, it would be of interest to monitor the situation at other workplaces with potentially higher risks of contamination. Simultaneous measurements of (14)C in hair and urine with additional random measurements of (14)C in faeces and exhaled air could provide a means of improving dose estimates for workers handling different types of (14)C-containing substances.
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| 24. |
- Sydoff, Marie, et al.
(författare)
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ABSOLUTE QUANTIFICATION OF ACTIVITY CONTENT FROM PET IMAGES USING THE PHILIPS GEMINI TF PET/CT SYSTEM.
- 2010
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; Apr 7, s. 236-239
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Tidskriftsartikel (refereegranskat)abstract
- Positron emission tomography combined with computed tomography (PET/CT) is a quantitative technique suitable for diagnostics and uptake measurements. The quantitative results can be used for the purpose of the calculating absorbed dose to patients undergoing nuclear medicine investigations. Hence, the accuracy of the quantification of the activity content in organs or tissues is of great importance. When using a planar gamma camera and single photon emission computed tomography (SPECT) images, the activity content in organs and tumours has to be determined by the user, using the number of counts in the organs and the efficiency of the camera. However, when using a Philips Gemini TF PET/CT system, the activity concentration in a region of interest (ROI) is given by the system. The reliability of activity concentration values given by the Philips Gemini TF PET/CT system was studied using a Jaszczak phantom containing hot spheres of different sizes; the influence of the ROI size and the impact of organ size, that is the partial volume effect, was investigated with three different lesion-to-background ratios in the phantom. The use of a small ROI size (40 % of the large ROI size, which covered the entire sphere) showed a 15 % improvement in the recovery of the true activity. Small lesion sizes result in large underestimations of the activity concentration values.
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| 26. |
- Sydoff, Marie, et al.
(författare)
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Use of wall-less (18)F-doped gelatin phantoms for improved volume delineation and quantification in PET/CT.
- 2014
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 59:5, s. 1097-1107
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Tidskriftsartikel (refereegranskat)abstract
- Positron emission tomography (PET) with (18)F-FDG is a valuable tool for staging, planning treatment, and evaluating the treatment response for many different types of tumours. The correct volume estimation is of utmost importance in these situations. To date, the most common types of phantoms used in volume quantification in PET utilize fillable, hollow spheres placed in a circular or elliptical cylinder made of polymethyl methacrylate. However, the presence of a non-radioactive sphere wall between the hotspot and the background activity in images of this type of phantom could cause inaccuracies. To investigate the influence of the non-active walls, we developed a phantom without non-active sphere walls for volume delineation and quantification in PET. Three sizes of gelatin hotspots were moulded and placed in a Jaszczak phantom together with hollow plastic spheres of the same sizes containing the same activity concentration. (18)F PET measurements were made with zero background activity and with tumour-to-background ratios of 12.5, 10, 7.5, and 5. The background-corrected volume reproducing threshold, Tvol, was calculated for both the gelatin and the plastic spheres. It was experimentally verified that the apparent background dependence of Tvol, i.e., a decreasing Tvol with increasing background fraction, was not present for wall-less spheres; the opposite results were seen in plastic, hollow spheres in commercially-available phantoms. For the types of phantoms commonly used in activity quantification, the estimation of Tvol using fillable, hollow, plastic spheres with non-active walls would lead to an overestimate of the tumour volume, especially for small volumes in a high activity background.
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| 27. |
- Söderberg, Marcus, et al.
(författare)
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Evaluation of image reconstruction methods for 123I-MIBG-SPECT: a rank-order study.
- 2012
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Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 53:7, s. 778-784
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is an opportunity to improve the image quality and lesion detectability in single photon emission computed tomography (SPECT) by choosing an appropriate reconstruction method and optimal parameters for the reconstruction. Purpose: To optimize the use of the Flash 3D reconstruction algorithm in terms of equivalent iteration (EI) number (number of subsets times the number of iterations) and to compare with two recently developed reconstruction algorithms ReSPECT and orthogonal polynomial expansion on disc (OPED) for application on (123)I-metaiodobenzylguanidine (MIBG)-SPECT. Material and Methods: Eleven adult patients underwent SPECT 4 h and 14 patients 24 h after injection of approximately 200 MBq (123)I-MIBG using a Siemens Symbia T6 SPECT/CT. Images were reconstructed from raw data using the Flash 3D algorithm at eight different EI numbers. The images were ranked by three experienced nuclear medicine physicians according to their overall impression of the image quality. The obtained optimal images were then compared in one further visual comparison with images reconstructed using the ReSPECT and OPED algorithms.ResultsThe optimal EI number for Flash 3D was determined to be 32 for acquisition 4 h and 24 h after injection. The average rank order (best first) for the different reconstructions for acquisition after 4 h was: Flash 3D(32) > ReSPECT > Flash 3D(64) > OPED, and after 24 h: Flash 3D(16) > ReSPECT > Flash 3D(32) > OPED. A fair level of inter-observer agreement concerning optimal EI number and reconstruction algorithm was obtained, which may be explained by the different individual preferences of what is appropriate image quality. Conclusion: Using Siemens Symbia T6 SPECT/CT and specified acquisition parameters, Flash 3D(32) (4 h) and Flash 3D(16) (24 h), followed by ReSPECT, were assessed to be the preferable reconstruction algorithms in visual assessment of (123)I-MIBG images.
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| 28. |
- Söderberg, Marcus, et al.
(författare)
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Initial tests of a new phantom for investigation of spatial resolution, partial volume effect and detectability in nuclear medicine tomography
- 2011
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Ingår i: Journal of Physics Conference Series. - : IOP Publishing. - 1742-6596. ; 317:012017, s. 1-7
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedA new phantom has been designed that can provide simultaneously different target to background activity ratios with a linearly changing diameter of lesions. The purpose of the study was to describe and perform initial measurements with the phantom aimed to characterize different nuclear medicine tomographic systems and reconstruction algorithms in their performance and behaviour concerning partial volume effect (PVE) and detectability by varying the acquisition parameters and the count statistics. The phantom has an external vessel whose outline is half-cylindrical and allows it to be incorporated into an anthropomorphic thorax phantom. The phantom itself contains 16 fillable cones with an inner diameter linearly decreasing from 16 mm to 2 mm and a wall thickness of 1 mm acrylic glass. They as well as the outer vessel were separately filled with (99m)Tc-and (18)F-solutions respectively of different activity concentrations. The phantom was easy to fill and air bubbles could easily be avoided. Images taken using a SPECT/CT and a PET/CT system are presented as well as evaluations of PVE. The new phantom seems to be useful for comparison and optimisation of different acquisition and reconstruction parameters in nuclear medicine tomographic studies and for comparisons between various tomographic units.
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