| 1. |
- Ceberg, Sofie, et al.
(författare)
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Surface guided radiotherapy decreases the uncertainty in breast cancer patient setup
- 2018
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Konferensbidrag (refereegranskat)abstract
- (Sunday, 7/29/2018) 3:00 PM - 6:00 PMRoom: Exhibit HallPurpose: The aim was to investigate if the setup of breast cancer patients could be improved using surface guided radiotherapy, compared to the conventional method using lasers and skin markings.Methods: Forty-seven patients, who received tangential or locoregional adjuvant radiotherapy, were positioned using a surface-based setup (SBS). Thirty-eight patients were positioned using the conventional laser-based setup (LBS). For the patient group positioned using a SBS, correction for posture was performed under guidance of a color map projected onto the patients' skin in real time. The surface tolerance for the color map was 5 mm. For both setup techniques the deviation of the breast position was measured using verification images. In total, 897 images were analysed. The frequency distributions of the deviations were analysed.Results: The result showed a significant improvement in the interfractional variation of the setup deviation for SBS compared to the LBS (pConclusion: Conventional laser-based setup can be replaced by surface-based setup, both for tangential and locoregional breast cancer treatments.
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| 2. |
- Johnson, Louis Banka, et al.
(författare)
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Radiation enteropathy and leucocyte-endothelial cell reactions in a refined small bowel model
- 2004
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Ingår i: BMC Surgery. - : Springer Science and Business Media LLC. - 1471-2482. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Leucocyte recruitment and inflammation are key features of high dose radiation-induced tissue injury. The inflammatory response in the gut may be more pronounced following radiotherapy due to its high bacterial load in comparison to the response in other organs. We designed a model to enable us to study the effects of radiation on leucocyte-endothelium interactions and on intestinal microflora in the murine ileum. This model enables us to study specifically the local effects of radiation therapy. METHOD: A midline laparotomy was performed in male C57/Bl6 mice and a five-centimetre segment of ileum is irradiated using the chamber. Leucocyte responses (rolling and adhesion) were then analysed in ileal venules 2 - 48 hours after high dose irradiation, made possible by an inverted approach using intravital fluorescence microscopy. Furthermore, intestinal microflora, myeloperoxidase (MPO) and cell histology were analysed. RESULTS: The highest and most reproducible increase in leucocyte rolling was exhibited 2 hours after high dose irradiation whereas leucocyte adhesion was greatest after 16 hours. Radiation reduced the intestinal microflora count compared to sham animals with a significant decrease in the aerobic count after 2 hours of radiation. Further, the total aerobic counts, Enterobacteriaceae and Lactobacillus decreased significantly after 16 hours. In the radiation groups, the bacterial count showed a progressive increase from 2 to 24 hours after radiation. CONCLUSION: This study presents a refinement of a previous method of examining mechanisms of radiation enteropathy, and a new approach at investigating radiation induced leucocyte responses in the ileal microcirculation. Radiation induced maximum leucocyte rolling at 2 hours and adhesion peaked at 16 hours. It also reduces the microflora count, which then starts to increase steadily afterwards. This model may be instrumental in developing strategies against pathological recruitment of leucocytes and changes in intestinal microflora in the small bowel after radiotherapy.
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| 3. |
- Jönsson, Mattias, et al.
(författare)
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Technical evaluation of a laser-based optical surface scanning system for prospective and retrospective breathing adapted computed tomography.
- 2015
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Ingår i: Acta Oncologica. - 1651-226X. ; 54:2, s. 261-265
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Tidskriftsartikel (refereegranskat)abstract
- Background. For breathing adapted radiotherapy, the same motion monitoring system can be used for imaging and triggering of the accelerator. Purpose. To evaluate a new technique for prospective gated computed tomography (CT) and four-dimensional CT (4DCT) using a laser based surface scanning system (Sentinel(™), C-RAD, Uppsala, Sweden). The system was compared to the AZ-733V respiratory gating system (Anzai Medical, Tokyo, Japan) and the Real-Time Position Management System (RPM(™)) (Varian Medical Systems, Palo Alto, CA, USA). Material and methods. Temporal accuracy was evaluated using a moving phantom programmed to move a platform along trajectories following a sin(6)(ωt) function with amplitudes from 6 to 20 mm and periods from 2 to 5 s during 120 s while the motion was recorded. The recorded data was Fourier transformed and the peak area at the fundamental and harmonic frequencies compared to data generated using the same sinusoidal function. For verification of the 4DCT reconstruction process, the phantom was programmed to move along a sinusoidal trajectory. Ten phase series were reconstructed. The distance from the couch to the platform was measured in each image. By fitting the function sin(ωt-ϕ) to the values measured in the images corresponding to each slice, the phase of each image was verified. Results and conclusion. In the recorded data, the peak area at the fundamental frequency covered on average 104 ± 4%, 102 ± 4% and 91 ± 27% of the peak area in the generated data for the Sentinel(™), RPM(™) and AZ-733V systems, respectively. All systems managed to resolve both harmonic frequencies. The second experiment showed that all images were sorted into the correct series using breathing data recorded by each system. The systems generated very similar results, however, it is preferable to use the same system both for imaging and treatment.
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| 4. |
- Jönsson, Mattias, et al.
(författare)
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Technical evaluation of different motion-monitoring systems for respiratory gating in radiation therapy
- 2013
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Ingår i: Medical Physics in the Baltic States. - 1822-5721. ; , s. 38-41
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Konferensbidrag (refereegranskat)abstract
- The purpose of this work was to evaluate three motion-monitoring systems: Sentinel (TM), Catalyst (TM) (both C-RAD) and Real-time Position Management (RPM (TM)) system (Varian Medical Systems Inc) for respiratory gating in radiotherapy. To measure the systems. latency, an in-house built circuit with a microcontroller operating a piston was used. The trigger pulse was sent from the gating systems to the accelerator within 300 mu s. However, the response time of the accelerator could be over 300 ms
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| 5. |
- Kügele, Malin, et al.
(författare)
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Surface guided radiotherapy (SGRT) improves breast cancer patient setup accuracy
- 2019
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Ingår i: Journal of Applied Clinical Medical Physics. - : Wiley. - 1526-9914. ; , s. 61-68
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of the study was to investigate if surface guided radiotherapy (SGRT) can decrease setup deviations for tangential and locoregional breast cancer patients compared to conventional laser-based setup (LBS). Materials and Methods: Both tangential (63 patients) and locoregional (76 patients) breast cancer patients were enrolled in this study. For LBS, the patients were positioned by aligning skin markers to the room lasers. For the surface based setup (SBS), an optical surface scanning system was used for daily setup using both single and three camera systems. To compare the two setup methods, the patient position was evaluated using verification imaging (field images or orthogonal images). Results: For both tangential and locoregional treatments, SBS decreased the setup deviation significantly compared to LBS (P < 0.01). For patients receiving tangential treatment, 95% of the treatment sessions were within the clinical tolerance of ≤ 4 mm in any direction (lateral, longitudinal or vertical) using SBS, compared to 84% for LBS. Corresponding values for patients receiving locoregional treatment were 70% and 54% for SBS and LBS, respectively. No significant difference was observed comparing the setup result using a single camera system or a three camera system. Conclusions: Conventional laser-based setup can with advantage be replaced by surface based setup. Daily SGRT improves patient setup without additional imaging dose to breast cancer patients regardless if a single or three camera system was used.
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| 6. |
- Polistena, Andrea, et al.
(författare)
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Local radiotherapy of exposed murine small bowel : Apoptosis and inflammation
- 2008
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Ingår i: BMC Surgery. - : Springer Science and Business Media LLC. - 1471-2482. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background. Preoperative radiotherapy of the pelvic abdomen presents with complications mostly affecting the small bowel. The aim of this study was to define the features of early radiation-induced injury on small bowel. Methods. 54 mice were divided into two groups (36 irradiated and 18 sham irradiated). Animals were placed on a special frame and (in the radiated group) the exteriorized segment of ileum was subjected to a single absorbed dose of 19 or 38 Gy radiation using 6 MV high energy photons. Specimens were collected for histology, immunohistochemistry (IHC) and ELISA analysis after 2, 24 and 48 hours. Venous blood was collected for systemic leucocyte count in a Burker chamber. Results. Histology demonstrated progressive infiltration of inflammatory cells with cryptitis and increased apoptosis. MIP-2 (macrophage inflammatory protein) concentration was significantly increased in irradiated animals up to 48 hours. No significant differences were observed in IL-10 (interleukin) and TNF-α (tumour necrosis factor) levels. IHC with CD45 showed a significant increase at 2 hours of infiltrating leucocytes and lymphocytes after irradiation followed by progressive decrease with time. Caspase-3 expression increased significantly in a dose dependent trend in both irradiated groups up to 48 hours. Conclusion. Acute small bowel injury caused by local irradiation is characterised by increased apoptosis of crypt epithelial cells and by lymphocyte infiltration of the underlying tissue. The severity of histological changes tends to be dose dependent and may affect the course of tissue damage.
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| 7. |
- Rääf, Christopher, et al.
(författare)
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Human metabolism of radiocaesium revisited
- 2004
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 112:3, s. 395-404
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Tidskriftsartikel (refereegranskat)abstract
- Three adult volunteers (2 males and I female) have ingested radioactive caesium in two edible forms in order to compare the gastrointestinal uptake and the subsequent short-term and long-term biokinetics. Foodstuffs made of fresh-water fish or mushrooms from regions in Sweden of high Cs-137 deposition was ingested together with a (CsCl)-Cs-134-solution mixed with soft drinks. Whole-body countings of Cs-134 and Cs-137 were performed in the Malmo whole-body counter during a period of similar to50 d prior to, and 200-300 d after the ingestion. Urine and faeces were collected the day before and up to 7-10 d after the test meals, and analysed for Cs-134 and Cs-137. No significant difference in the gastrointestinal uptake fraction, f(0) = 0.98 between caesium incorporated into a foodstuff matrix and caesium in ionic form was detected. Cumulated faecal excretion during 7 d after ingestion accounted for 2-3% of the intake. No significant difference in the long-term biological half-time was found between caesium present in a food matrix and in an aqueous solution in any of the volunteers.
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| 8. |
- Rääf, Christopher, et al.
(författare)
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Urinary excretion measurements for the assessment of body burden of radiocaesium in man: differences between potassium and creatinine normalisation
- 1999
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Ingår i: Applied Radiation and Isotopes. - 0969-8043. ; 51:5, s. 505-514
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Tidskriftsartikel (refereegranskat)abstract
- Relationships between 24-h urinary excretion and body burden of 137Cs obtained in a south-Swedish population, together with data from the literature, were applied to urine samples collected in 1994-95 from adult subjects living in Russia, in order to estimate their average body burden of 137Cs. Estimates obtained through creatinine normalisation of the 137Cs content in the Russian urine were a factor of 2 higher than estimates obtained through potassium normalisation. The accuracy of both these normalisation methods is discussed, as well as the influence of the difference in dietary habits between the two populations.
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| 9. |
- Röme, Andrada, et al.
(författare)
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Critical Role of P-Selectin and Lymphocyte Function Antigen-1 in Radiation-Induced Leukocyte-Endothelial Cell Interactions in the Colon.
- 2007
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Ingår i: Diseases of the Colon & Rectum. - : Ovid Technologies (Wolters Kluwer Health). - 0012-3706. ; 50:12, s. 2194-2202
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Radiation therapy is frequently used in treating different types of tumors, although associated with serious side effects, such as fibrosis and complicated diarrhea. This study was designed to define the adhesive mechanisms behind radiotherapy-induced leukocyte recruitment in the colon. Methods All mice, except control animals, were radiated with a single dose of 20 Gy. Mice were pretreated with an isotype-matched control antibody or a monoclonal antibody directed against P-selectin. In separate experiments, lymphocyte function antigen-1–deficient animals were used. Leukocyte rolling and firm adhesion were determined by use of inverted intravital fluorescence microscopy 16 hours after radiation. Results It was found that immunoneutralization of P-selectin reduced leukocyte rolling by 83 percent and adhesion by 87 percent in radiated mice. Moreover, radiation-induced leukocyte adhesion in LFA-1-deficient mice was decreased by 94 percent compared with wild-type animals. Conclusions This study demonstrates that leukocyte rolling is mediated by P-selectin and that firm leukocyte adhesion is supported by lymphocyte function antigen-1 in radiation-induced enteritis. Moreover, P-selectin-dependent leukocyte rolling is a precondition for subsequent leukocyte adhesion in radiation-induced intestinal injury. Thus, targeting P-selectin and/or lymphocyte function antigen-1 may protect against pathologic inflammation in the colon induced by radiotherapy.
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| 10. |
- Röme, Andrada, et al.
(författare)
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Radiation-induced platelet-endothelial cell interactions are mediated by P-selectin and P-selectin glycoprotein ligand-1 in the colonic microcirculation.
- 2012
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Ingår i: Surgery. - : Elsevier BV. - 1532-7361 .- 0039-6060. ; 151:4, s. 606-611
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Antiplatelet reagents have been reported to protect against intestinal damage associated with abdominal radiotherapy, but the mechanisms behind radiation-induced platelet-endothelium interactions are not known. We sought to define the adhesive mechanisms that regulate radiotherapy-induced platelet-endothelial cell interactions in the colon. METHODS: All mice except the controls were exposed to abdominal radiation with a single dose of 20 Gray. Mice were pretreated with an isotype-matched control antibody or a monoclonal antibody directed against either P-selectin or P-selectin glycoprotein ligand-1 (PSGL-1). Platelet and leukocyte rolling and adhesion in the colon were determined by use of inverted intravital fluorescence microscopy 16 hours after radiation. Radiation-induced intestinal leakage of fluorescein isothiocyanate-conjugated dextran was examined in separate experiments. RESULTS: Immunoneutralization of P-selectin decreased radiation-provoked platelet rolling by 87% and adhesion by 63%. Moreover, inhibition of PSGL-1 decreased platelet rolling and adhesion by 77% and 83%, respectively, in animals exposed to radiation. Similarly, inhibition of P-selectin and PSGL-1 decreased radiation-induced leukocyte rolling and adhesion by more than 84% and 90%, respectively, in the colon. In contrast, inhibition of P-selectin or PSGL-1 had no impact on radiation-induced intestinal leakage. In addition, systemic depletion of platelets and leukocytes did not affect intestinal barrier dysfunction in radiated animals. CONCLUSION: This study demonstrates that radiation-provoked platelet and leukocyte accumulation are mediated in part by P-selectin and PSGL-1. Radiation-induced gut leakage, however, is independent of accumulation of platelets and leukocytes in the intestinal microvasculature.
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| 11. |
- Sahlén Helmer, Charlotte, et al.
(författare)
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A Randomized Trial of Continuous Versus Intermittent Skin-to-Skin Contact After Premature Birth and the Effects on Mother-Infant Interaction
- 2020
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Ingår i: Advances in Neonatal Care. - : Lippincott Williams & Wilkins. - 1536-0903 .- 1536-0911. ; 20:3, s. E48-E56
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Tidskriftsartikel (refereegranskat)abstract
- Background: Premature birth affects opportunities for interaction between infants and mothers. Skin-to-skin contact (SSC) is standard care in neonatal care but has not been sufficiently studied regarding the effects on interaction between preterm infant and mothers. Purpose: The purpose of this study was to compare interaction between preterm infants and their mothers after continuous versus intermittent SSC from birth to discharge. A secondary aim was to study a potential dose-response effect between time in SSC and quality of interaction. Methods: Families were randomly assigned to either continuous (n = 17) or intermittent (n = 14) SSC before delivery. Interaction was measured from videotapes of a Still-Face Paradigm collected at 4 months corrected age. Face-to-face interaction was coded according to Ainsworths Maternal Sensitivity Scales and the Maternal Sensitivity and Responsivity Scales-R. Dose-response correlations were calculated between mean time spent in SSC and each of the interaction scales. Results: There were no statistically significant differences between groups in maternal interactive behavior toward their infants regarding sensitivity, interference, availability, acceptance, withdrawal, or intrusivity. There was no correlation between mean time in SSC and quality of interaction. Implications for Practice: Continuous SSC from birth to discharge was not superior to intermittent SSC concerning mother-infant interaction between preterm infants and their mothers at 4 months corrected age. However, compared with other studies, mean time in SSC was also high in the intermittent group. Implications for Research: Further studies are needed to find out how interaction between parents and preterm infants can be improved, supported, and facilitated in the neonatal intensive care unit (NICU) and whether there is an optimal dose for SSC.
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| 12. |
- Sahlén Helmer, Charlotte, et al.
(författare)
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An Early Collaborative Intervention Focusing on Parent-Infant Interaction in the Neonatal Period : A Descriptive Study of the Developmental Framework
- 2021
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 18:12
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Tidskriftsartikel (refereegranskat)abstract
- Moderate to late preterm infants are at risk of developing problems later in life. To support attachment and infants development, high quality parent-infant interaction is important. Parent-infant interaction is known to improve through intervention programs but since no such intervention program is addressed directly to moderate to late preterm infants, a tailor-made intervention was developed. The aim was to describe the rationale, development, framework and practical provision of a new early collaborative intervention program. This study has a descriptive design and the intervention is described using the Template for Intervention Description and Replication. During an intervention-session, the preterm infants cues are made visible to the parents as they perform an everyday care-taking procedure. Instant feedback is delivered to give the parents the opportunity to notice, interpret and respond to cues immediately. The infants response to the parents action is discussed in a dialogue to instantly guide parents awareness of the preterm infants subtle cues. This study describes a new early collaborative intervention, developed to support interaction between parents and their moderate to late preterm infants starting in the neonatal intensive care unit. Clinical studies evaluating parental experiences as well as the effects of the early intervention are ongoing, ClinicalTrials.gov NCT02034617.
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| 13. |
- Sahlén Helmer, Charlotte, 1971-
(författare)
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Interaction between preterm infants and their parents : Studies of early interventions in neonatal care
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Preterm birth negatively affects infant well-being and development. A well-functioning parent-infant interaction can mitigate the risk of preterm birth on infant development. However, parent-infant interaction is often disrupted after preterm birth because of organizational factors in care, infants’ immature interaction cues, and maternal health problems. Different interventions supporting parental-infant interaction exist, but only a few target support for interaction between preterm infants born at gestational week 30-36 and their parents. Thus, an early, feasible and effective intervention that supports the preterm infant and the parents in the neonatal intensive care unit was needed. Aim The overall aim of the thesis was two-fold; first to evaluate the early intervention skin-to-skin contact on mother-infant interaction; and second, to develop a new intervention, the Early Collaborative Intervention (EACI), to explore how mothers’ experience the new intervention, and to study its effects on mother-infant interaction. Methods Study I was a randomized controlled trial with two groups. Families were randomly assigned to either continuous or intermittent skin-to-skin con-tact directly after birth. Mother-infant interaction was video recorded when the infant was four months corrected age during a Still face procedure. The interaction was later scored using two different instruments, the Ains-worth’s Maternal Sensitivity Scales and the Maternal Sensitivity and Responsivity Scale. Furthermore, the dose-response relationship between time in skin-to-skin contact and interaction quality was calculated. Study II had a descriptive design where the rationale, development, frame-work, and practical provision of the EACI program was described. Study III had a qualitative design. Mothers were interviewed about their experiences of the EACI. Data were analyzed with reflexive thematic analysis. Study IV was a randomized controlled trial with two groups. Families were randomly assigned to either the EACI or standard care. The intervention started within three days after birth. Mother-infant interaction was video recorded when the infant was one month corrected age during a bathing session. The interaction was later scored using two different instruments, the Ainsworth’s Maternal Sensitivity Scales, and the Emotional Availability system. Intention to treat and per protocol analysis were calculated as three sessions were considered the minimum required to detect a difference. Results Study I showed no significant differences in maternal interaction behavior between the groups randomized to continuous skin-to-skin contact or intermittent skin-to-skin contact. Dose-response calculations between time in skin-to-skin-contact and interaction quality showed no correlations. In Study II, the theoretical framework of the EACI was based on the attachment theory, the assessment of infant behavior described by Brazelton, and psychoeducational theory. The rationale was to provide tailored early support that improved parent-infant interaction and thereby optimized infant well-being and development. The intervention was developed by a core group in the neonatal intensive care unit at Crown Princess Victoria Children’s Hospital. It was a three-session intervention, provided during an ordinary care procedure with instant provider feedback and hands on guidance during active parental involvement. Two sessions were provided at the hospital, and one after discharge in the home of the family. In Study III two main themes were constructed, “mothers feelings evoked from the Early Collaborative Intervention” and “based on the preterm baby’s behavior”. The mothers experienced the intervention as helpful for their interaction with the infant and for them to see their infant as an individual. The per protocol analysis in Study IV showed that the intervention group had significantly higher mean scores in the Availability, Acceptance and Non-hostility subscales, indicating a more well-functioning interaction. Conclusion Continuous SSC was not superior to intermittent SSC for improving maternal interactive behavior. In contrast, the Early Collaborative Intervention, improved maternal interactive behavior if all three sessions of the intervention were provided. This was also confirmed in the interviews, in which the mothers described the intervention as helpful for their interactive behavior with their preterm infants.
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| 14. |
- Sahlén Helmer, Charlotte, et al.
(författare)
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Mothers experiences of a new early collaborative intervention, the EACI, in the neonatal period : A qualitative study
- 2023
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Ingår i: Journal of Clinical Nursing. - : Wiley. - 0962-1067 .- 1365-2702. ; 32:11-12, s. 2892-2902
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Tidskriftsartikel (refereegranskat)abstract
- Aim To explore mothers experiences of the EArly Collaborative Intervention. Background Preterm birth puts a considerable emotional and psychological burden on parents and families. Parents to moderate and late premature infants have shorter stays at the neonatal intensive care unit and have described a need for support. The EArly Collaborative Intervention was developed to support parents with preterm infants born between gestational Weeks 30 to 36. In this study, mothers experiences of the new intervention were explored. Design A qualitative design guided by a reflexive thematic analysis according to Braun and Clarke. Interviews were individually performed with 23 mothers experienced with the EArly Collaborative Intervention. Data were identified, analysed and reported using reflexive thematic analysis. The COREQ checklist was used preparing the manuscript. Results Two main overarching themes were constructed. The first theme, mothers feelings evoked from the EArly Collaborative Intervention describes the emotions raised by the intervention and how the intervention affected their parental role. Their awareness of the preterm babys behaviour increased, and the intervention helped the parents to communicate around their babys needs. The second theme, based on the preterm babys behavior, describes experiences of the provision and the learning process about their preterm babys needs and communication. The intervention was experienced as helpful both immediately and for future interaction with the baby. Conclusions Mothers found the intervention to be supportive and encouraging. They came to look upon their baby as an individual, and the new knowledge on how to care and interact with their baby affected both their own and their babys well-being. Furthermore, the intervention felt strengthening for their relationship with the other parent. Relevance to Clinical Practice The EArly Collaborative Intervention can support parents abilities as well as their relation to their baby and may thereby contribute to infant development, cognition and well-being.
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| 15. |
- Stenström, Kristina, et al.
(författare)
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14C emission from Swedish nuclear power plants and its Eeffect on the 14C levels in the environment
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The radionuclide 14C is produced in all types of nuclear reactors mainly by neutron-induced reactions in oxygen (17O), nitrogen (14N) and carbon (13C). Part of the 14C created is continuously released during normal operation as airborne effluents in various chemical forms (such as CO2, CO and hydrocarbons) to the surroundings. Because of the biological importance of carbon and the long physical half-life of 14C, it is of interest to measure the releases and their incorporation into living material. The 14C activity concentrations in annual tree rings and air around two Swedish nuclear power plants (Barsebäck and Forsmark) as well as the background 14C activity levels from two reference sites in southern Sweden during 1973-1996 are presented in this report. In order to verify the reliability of the method some investigations have been conducted at two foreign nuclear sites, Sellafield fuel reprocessing plant in England, and Pickering nuclear generating station in Canada, where the releases of 14C are known to be substantial. Furthermore, results from some measurements in the vicinity of Paldiski submarine training centre in Estonia are presented. The results of the 14C measurements of air, vegetation and annual tree rings around the two Swedish nuclear power plants show very low enhancements of 14C, if at all above the uncertainty of the measurements. Even if the accuracy of the measurements of the annual tree rings is rather good (1-2%) the contribution of 14C from the reactors to the environment is so small that it is difficult to separate it from the prevailing background levels of 14C. This is the case for all sampling procedures: in air and vegetation as well as in annual tree rings. Only on a few occasions an actual increase is observed. However, although the calculations suffer from rather large uncertainties, the calculated release rate from Barsebäck is in fair agreement with reported release data. The results of this investigation show that the effective doses to man related to the releases of 14C from the Swedish light-water reactors at Barsebäck and Forsmark are very low, especially compared to the situation at other nuclear installations, such as the fuel reprocessing plant at Sellafield, England, and the heavy-water reactors at Pickering nuclear generating station, Canada. Lund/Malmö February 2000
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| 16. |
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| 17. |
- Thornberg, Charlotte
(författare)
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Irradiation of members of the general public from radioactive caesium following the Chernobyl reactor accident. Field studies in a highly contaminated area in the Bryansk region, Russia.
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- From 1990 to 1998, estimations of the effective dose from external as well as internal irradiation from 137Cs and 134Cs were carried out for inhabitants in rural villages in the Bryansk region, Russia, highly contaminated due to the Chernobyl accident in 1986. The villages were situated about 180 km from the Chernobyl power plant and the deposition of 137Cs was in the range 0.9-2.7 MBq m-2. Yearly expeditions were conducted in autumn by members of the Departments of Radiation Physics in Malmö and Göteborg, Institute of Radiation Hygiene, St. Petersburg, and the first years also the Norwegian Radiation Protection Authority. The dose levels and their change in time were investigated for various groups of the general public. The body burden of 137,134Cs, and hence, the effective dose, was estimated from measurements of the urinary concentration of caesium radionuclides, together with direct measurements of the body content using a portable detector. The effective dose from external irradiation was estimated from measurements with thermoluminescent (TL)-dosemeters worn by the participants during one month each year. In a special case study, the changes in biokinetics of 137Cs during pregnancy was investigated in a woman with an unintended intake of 137Cs via mushrooms from a highly contaminated forest in the area. During pregnancy there is an increased excretion of caesium resulting in a biological half-time of caesium which was 54% of the half-time before pregnancy. The ratio of the 137Cs concentration in breast milk (Bq L-1) to that in the mother’s body (Bq kg-1) was 15% one month after the child was born. The body burden of 137Cs in the Russian individuals calculated from the concentration of 137Cs in urine showed a good agreement with the body burden estimated from in vivo measurements in the same individuals. Normalisation of the caesium concentration in the urine samples by the use of potassium or creatinine excretion was found to introduce systematic differences as well as a larger spread in the calculated values of the 137Cs body burden as compared with calculations without normalisation, using the urinary concentration of 137Cs only. The yearly effective dose from external and internal irradiation to inhabitants in the Russian villages varied between 1.2 and 2.5 mSv as a mean for all villages studied between 1991 and 1998 and the internal effective dose was, on average, 30-50% of the total effective dose during that period. The effective dose from external irradiation decreased on average 15% per year, while the effective dose from internal irradiation varied, depending to a great extent on dietary habits and especially the availability of mushrooms. The cumulated effective dose for a 70-year period after the accident was calculated to be around 100 mSv with the assumption that the effective dose will decrease by only the physical decay of 137Cs (2% per year) after 1998. Individuals may receive considerably higher effective doses, up to 0.5 Sv during a life-time considering the large spread in dose values among individuals.
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