| 1. |
- Magnander, Tobias, et al.
(author)
-
Comparison of the accuracy in kidney activity concentration estimates by the conjugate view and posterior view methods
- 2015
-
In: Optimisation in X-ray and Molecular Imaging 2015 - the Fourth Malmö Conference on Medical Imaging, Gothenburg, Sweden, 28-30 May 2015.
-
Conference paper (other academic/artistic)abstract
- Purpose: In nuclear medicine the conjugate view method (CV) is the most common method for activity quantifications in planar images. The advantage with the CV method is its depth independence, i.e. the activity concentrations can be calculated from two opposite planar images without the knowledge of depth. However, one disadvantage of the method that the signal to background ratio is dependent on the location of the object. This effect might increase the inaccuracy in the activity concentration estimates. Therefore, the activity in off-center objects might be better estimated by the camera projection with the shortest camera to object distance. The aim of the present study was to compare the CV method with a posterior-anterior (PA) projection method for estimation of 177Lu activity concentrations in the kidneys. Methods: The two methods were used to retrospectively determine and compare the left and right kidney activity concentration in 20 patients treated with 177Lu-DOTA-octreotate at Sahlgrenska University Hospital. The kidney was segmented in the SPECT or CT image using an appropriate segmentation algorithm. An attenuation map for 177Lu was created from the CT. Attenuated planar AP and PA projections were created from the SPECT and the attenuation map. The kidney VOI was projected onto the AP and PA projections. The activity concentration in the kidney was calculated using both the PA projection method (ACPA) and the CV method (ACCV) and the results were compared to the concentration in the kidney VOI in the SPECT. Results: The mean ratio between ACCV and the SPECT determined activity concentration was 1.99 with a standard deviation (SD) equal to 1.03 and the mean ratio between ACPA and the SPECT determined concentration was 1.66 with SD=0.80. Both methods demonstrated that the main problems with activity estimates from planar images are the influences of attenuation and the activity concentration in the under and overlying tissues. Conclusions: The present study shows that a true background estimate cannot be accurately performed with neither the CV nor the PA method and that the difficulties in obtaining a true background affect the CV method more than the PA method. The study indicates that the PA method gives a more accurate estimate of the kidney activity concentration than the CV method.
|
|
| 2. |
- Hagmarker, Linn, et al.
(author)
-
Characterisation of a planar dosimetry method estimating the absorbed dose to the bone marrow during 177Lu-DOTATATE treatment
- 2016
-
In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer. - 1619-7070 .- 1619-7089.
-
Conference paper (other academic/artistic)abstract
- Aim: An image based method for bone marrow dosimetry, earlier presented by our research group, has shown a significant correlation between the absorbed dose to the bone marrow and haematological toxicity in 177Lu-DOTATATE treatment. The aim of this study was to further evaluate and optimise the method. Materials and Methods: 46 patients with advanced neuroendocrine tumours were treated with 177Lu -DOTATATE on 2-6 occasions. The patients were evaluated using the 4 planar gamma camera images collected at 2, 24, 48 and 168 hours after injection. The whole body was divided into a high- and a low uptake compartment, using a threshold based segmentation tool in the image platform PhONSAi, developed in-house. The segmentation tool starts by including the highest uptake focus and then gradually includes foci with lower and lower uptakes until a threshold is reached where the number of foci escalates. The threshold determines the proportion of the foci that is included in the two compartments. Visual inspection was used to determine the threshold valuewhere all high uptake tissues (i.e. kidney, spleen, liver and tumours) were included in the high uptake compartment. For thresholds around this value the activity in the two compartments was determined by the conjugate view method and the bonemarrow dose was calculated as a sum of the self and cross dose in the low uptake compartment and the cross dose from the high uptake compartment. Results: The visual analysis implies a threshold value of 10%of the maximum number of foci. A correlation was found between the absorbed bone marrow dose and haematological toxicity with p-values ranging from 0.001 to 0.02 for thresholds between 2 % and 25 %, the strongest correlation was found at 15 %. The mean absorbed bone marrow dose were 0.20-0.22 Gy per 7.4 GBq for threshold values between 10-25 %, and increased to 0.28 Gy for the lower values. No significant difference was observed in coefficient of variation (8.2-8.7 %) for the individual mean absorbed doses when varying the threshold value. Conclusion: The individual variation in absorbed dose is maintained at a low level when varying the threshold value for the determination of the compartment sizes. This implies that the method is stable for estimation of bone marrow doses and its correlation to haematological toxicity.
|
|
| 3. |
- Hagmarker, Linn, et al.
(author)
-
Evaluation of planar versus hybrid SPECT image methodology for bone marrow dosimetry during 177Lu-DOTATATE treatments reveals the obstacles with bone marrow metastases and cross-irradiation for the SPECT activity concentration quantification
- 2018
-
In: 31st Annual Congress of the European Association of Nuclear Medicine (EANM’18). 13-17 October, Dusseldorf, Germany.
-
Conference paper (other academic/artistic)abstract
- Introduction. The aim of this study is to compare the recently developed planar image-based method for bone marrow dosimetry with a hybrid method using SPECT/CT imaging at 24 h.p.i. of 177Lu-DOTATATE. Predictive ability of the methods is compared by investigating correlations of determined absorbed bone marrow dose, with haematological toxicity during the course of four treatment cycles. The aim is also to investigate the activity distribution in the vertebral column, and how the hybrid methodology can be optimized. Methods and Materials. 45 patients with advanced neuroendocrine tumours treated with 177Lu-DOTATATE at Sahlgrenska University Hospital in 2011-2016 (ILUMINET-study, EUDRACT nr 2011-etc) were included in this study. Absorbed bone marrow doses were calculated as the sum of the cross-doses from high-uptake organs and the remainder of the body, and the self-dose. Cross-doses were determined by time-activity curves created using planar images and a two-compartment method in the image platform PhONSAi. The self-dose was calculated using the time-activity concentration curve for the remainder of the body adjusted with the activity concentration determined in spheres placed in the vertebral bodies in SPECT-images. To improve recovery and reduce cross-irradiation of false counts in the SPECT-image, we utilized the Monte Carlo based reconstruction code SARec. Three activity concentrations were calculated to represent the activity concentration in the bone marrow; one mean (mean SPECT) and one median (median SPECT) activity concentration based on all visible vertebras and one where vertebras enclosing metastases were manually excluded (w/o Mets SPECT). Results. The planar method, the hybrid methods mean SPECT, median SPECT, and w/o Mets SPECT, yielded absorbed bone marrow doses after treatment cycle one at 0.19 (0.12-0.32), 0.35 (0.12-1.25), 0.29 (0.11-0.92) and 0.29 (0.15-0.81) Gy/7.4 GBq, respectively. A significant dose-response relationship was established after treatment cycle one between decreased platelet counts and absorbed bone marrow dose using the planar method (p=0.025, r=-0.16). With hybrid methods, a significant correlation was firstly found after treatment cycle two between absorbed dose and decreased platelet counts using median SPECT (p=0.018, r=-0.35). Conclusion. Early significant dose-response relationships were established. Despite using SARec-reconstructed SPECT-imaging for specific measurement of activity concentration in bone marrow cavities, the hybrid methods were not able to perform better than the planar method. The hybrid methods yielded higher absorbed bone marrow doses compared to the planar method as both bone metastases and cross-irradiation will influence the activity quantification. Further studies on minimizing influence of bone metastases and cross-irradiation are on-going.
|
|
| 4. |
- Hemmingsson, Jens, 1986, et al.
(author)
-
Autoradiography and biopsy measurements of a resected hepatocellular carcinoma treated with 90 yttrium radioembolization demonstrate large absorbed dose heterogeneities
- 2018
-
In: Advances in Radiation Oncology. - : Elsevier BV. - 2452-1094. ; 3:3, s. 439-446
-
Journal article (peer-reviewed)abstract
- © 2018 The Authors Purpose: Radioembolization is an alternative palliative treatment for hepatocellular carcinoma. Here, we examine the uptake differences between tumor tissue phenotypes and present a cross-section of the absorbed dose throughout a liver tissue specimen. Methods and materials: A patient with hepatocellular carcinoma was treated with90Y radioembolization followed by liver tissue resection. Gamma camera images and autoradiographs were collected and biopsy tissue samples were analyzed using a gamma well counter and light microscopy. Results: An analysis of 25 punched biopsy tissue samples identified 4 tissue regions: Normal tissue, viable tumor tissue with and without infarcted areas, and tumor areas with postnecrotic scar tissue. Autoradiography and biopsy tissue sample measurements showed large dose differences between viable and postnecrotic tumor tissue (159 Gy vs 23 Gy). Conclusions: Radioembolization of 90 yttrium with resin microspheres produces heterogeneous-absorbed dose distributions in the treatment of unifocal hepatic malignancies that could not be accurately determined with current gamma camera imaging techniques.
|
|
| 5. |
|
|
| 6. |
- Högberg, Jonas, 1976, et al.
(author)
-
Bremsstrahlung imaging of 90Y microspheres shows poor resemblance with distributions of 99mTc-MAA in liver
- 2010
-
In: Journal of the European Society of Therapeutic Radiology and Oncology. - 0167-8140. ; 94:1, s. 25-26
-
Conference paper (other academic/artistic)abstract
- PURPOSE To study the resemblance between the distributions of pre- therapeutic 99mTc-MAA and therapeutic 90Y-microspheres, used for ra- dioembolization of liver tumours, making use of gamma- and bremsstrahlung imaging. Furthermore, to establish the accuracy of this method by compar- isons of spatial resolution and radioactivity, performed on line source in water phantom and on resected tumour and normal liver from patients previously treated with 90Y-microspheres. MATERIALS 3 patients diagnosed with liver tumours and planned for surgery; 1 with hepatocellular carcinoma and 2 with cholangiocarcinoma, were treated with SIRTEX R © 90Y-microspheres after standard diagnostic SPECT/CT imag- ing with 99mTc-MAA. The images acquired with gamma camera were com- pared regarding distributions of radioactivity; gamma radiation from the 99mTc-MAA distributions and bremsstrahlung from the distributions of 90Y- microspheres (the latter with a wide bremsstrahlung energy window). Resec- tions of tumour- and some normal liver tissues were performed on all three patients; the resected tissues were sliced, smaller samples were punched out and the radioactivity was measured with a NaI-detector. Furthermore, autoradiography was performed on some slices. A line source with the in- ner diameter 1 mm was positioned in a cylindrical water phantom with the diameter 20 cm; first the line source was filled with 99mTc, then emptied and filled with 90Y. SPECT/CT imaging was performed on both line source se- tups. The spatial resolutions for both radionuclides were then compared. The results from the imaging comparisons performed on the patients were then evaluated with the complementary radiological methods described above. RESULTS The comparison of images from 99mTc-MAA and 90Y showed a considerable deviance in activity distribution for two of the patients. One ex- ample is shown in the figure, the upper image showing 99mTc-MAA and the lower showing 90Y-microspheres. The moderate difference in spatial resolu- tions for 99mTc and 90Y, (15 vs 18 mm FWHM) confirmed the accuracy of these findings. The other radiological methods did also confirm the macro- scopic activity distribution as shown with bremsstrahlung imaging. CONCLUSIONS Bremsstrahlung imaging is a satisfying and reliable method in showing the actual macroscopic distribution of therapeutic 90Y-microspheres used for radioembolization of liver tumours. The results further demonstrate the need for a better diagnostic method than the one currently used, with 99mTc-MAA, thereby providing a better pre-dosimetry; hopefully with a better selection of patients, regarding tumour regression and a lower risk of liver failure.
|
|
| 7. |
- Högberg, Jonas, 1976, et al.
(author)
-
Heterogeneity of microsphere distribution in resected liver and tumour tissue following selective intrahepatic radiotherapy
- 2014
-
In: EJNMMI Research. - : Springer Science and Business Media LLC. - 2191-219X. ; 4:48
-
Journal article (peer-reviewed)abstract
- BACKGROUND Selective arterial radioembolisation of liver tumours has increased, because of encouraging efficacy reports; however, therapeutic parameters used in external beam therapy are not applicable for understanding and predicting potential toxicity and efficacy, necessitating further studies of the physical and biological characteristics of radioembolisation. The aim was to characterise heterogeneity in the distribution of microspheres on a therapeutically relevant geometric scale considering the range of yttrium-90 (90Y) β-particles. METHODS Two patients with intrahepatic cholangiocarcinoma, marginally resectable, were treated by selective arterial embolisation with 90Y resin microspheres (SIRTEX®), followed 9 days post-infusion by resection, including macroscopic tumour tissue and surrounding normal liver parenchyma. Formalin-fixed, sectioned resected tissues were exposed to autoradiographic films, or tissue biopsies of various dimensions were punched out for activity measurements and microscopy. RESULTS Autoradiography and activity measurements revealed a higher activity in tumour tissue compared to normal liver parenchyma. Heterogeneity in activity distribution was evident in both normal liver and tumour tissue. Activity measurements were analysed in relation to the sample mass (5 to 422 mg), and heterogeneities were detected by statistical means; the larger the tissue biopsies, the smaller was the coefficient of variation. The skewness of the activity distributions increased with decreasing biopsy mass. CONCLUSIONS The tissue activity distributions in normal tissue were heterogeneous on a relevant geometric scale considering the range of the ionising electrons. Given the similar and repetitive structure of the liver parenchyma, this finding could partly explain the tolerance of a relatively high mean absorbed dose to the liver parenchyma from β-particles. Keywords: Radioembolisation; Y-90; SIR; Surgery; Activity heterogeneity
|
|
| 8. |
- Högberg, Jonas, 1976, et al.
(author)
-
Increased absorbed liver dose in Selective Internal Radiation Therapy (SIRT) correlates with increased sphere-cluster frequency and absorbed dose inhomogeneity
- 2015
-
In: EJNMMI Physics. - : Springer Science and Business Media LLC. - 2197-7364. ; 2:1
-
Journal article (peer-reviewed)abstract
- Background The higher tolerated mean absorbed dose for selective internal radiation therapy (SIRT) with intra-arterially infused 90Y microspheres compared to external beam therapy is speculated to be caused by absorbed dose inhomogeneity, which allows for liver regeneration. However, the complex liver microanatomy and rheology makes modelling less valuable if the tolerance doses are not based on the actual microsphere distribution. The present study demonstrates the sphere distribution and small-scale absorbed dose inhomogeneity and its correlation with the mean absorbed dose in liver tissue resected after SIRT. Methods A patient with marginally resectable cholangiocarcinoma underwent SIRT 9 days prior to resection including adjacent normal liver tissue. The resected specimen was formalin-fixed and sliced into 1 to 2-mm sections. Forty-one normal liver biopsies 6-8 mm in diameter were punched from these sections and the radioactivity measured. Sixteen biopsies were further processed for detailed analyses by consecutive serial sectioning of 15 30-μm sections per biopsy, mounted and stained with haematoxylin-eosin. All sections were scrutinised for isolated or conglomerate spheres. Small-scale dose distributions were obtained by applying a 90Y-dose point kernel to the microsphere distributions. Results A total of 3888 spheres were found in the 240 sections. Clusters were frequently found as strings in the arterioles and as conglomerates in small arteries, with the largest cluster comprising 453 spheres. An increased mean absorbed dose in the punch biopsies correlated with large clusters and a greater coefficient of variation. In simulations the absorbed dose was 5–1240 Gy; 90% were 10-97 Gy and 45% were <30 Gy, the assumed tolerance in external beam therapy. Conclusions Sphere clusters were located in both arterioles and small arteries and increased in size with increasing sphere concentration, resulting in increased absorbed dose inhomogeneity, which contradicts earlier modelling studies.
|
|
| 9. |
- Högberg, Jonas, 1976, et al.
(author)
-
On the dose heterogeneity in normal liver tissue due to treatment of liver tumors with yttrium-90 microspheres
- 2012
-
In: 25th Annual Congress on European Association of Nuclear Medicine, Milano, Italy, October 27-31, 2012. European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 39:suppl 2
-
Conference paper (other academic/artistic)abstract
- Aim: When treating patients with primary or metastatic liver cancer, applying external radiotherapy, an absorbed dose of 30 - 35 Gy to the whole normal liver tissue volume is associated with a 5 % risk of radiation-induced hepatitis. If less than half of the normal liver volume is being exposed, the threshold for a 5 % risk of hepatitis is increased to above 60 Gy for both primary and metastatic liver cancer. Experience with patients treated with SIR-Spheres® (Sirtex Medical Ltd.), resin microspheres aggregated with yttrium-90, has shown that most patients tolerate an average absorbed dose to normal liver tissue higher than 60 Gy. The high tolerance for this treatment procedure can probably be explained by the resulting heterogenic distribution of radioactivity. It is of interest to study the degree of heterogeneity in the distribution of radioactivity in normal liver tissue, in order to explain or even predict the tolerance to radiation. The aim of this study was to describe the degree of heterogeneity by comparing the relative standard deviations of the radioactivity concentration for different sample mass categories. Materials and Methods: Two patients with cholangiocarcinoma were planned for a combined treatment with yttrium-90-aggregated SIR-Spheres followed by surgery 9 days after radiotherapy. According to standard protocol for treatments with SIR-Spheres, the therapies were preceded by Tc-99m-labled Macro aggregated albumin (Tc-99m-MAA) distribution studies for pre-therapeutic dosimetry and lung shunting evaluations. After surgery the resected tissue, containing both tumour and normal tissue, was studied regarding the distribution of radioactivity. Several small circular samples of normal liver tissue were punched out from 2 mm thick slices of resected tissue, deliberately varying the sizes, and thus the masses of the tissue samples (from 6 to 102 mg). The samples were weighed and categorized in two (first patient) and three (second patient) groups, depending on sample mass. After this the radioactivity was measured with a NaI(Tl) detector. The relative standard deviations (SD/Median) for the radioactivity concentration for each sample mass group were determined and compared. Results: The relative standard deviation for the radioactivity concentration was decreasing rapidly with increasing sample mass. Conclusion: The results indicate a considerable degree of heterogeneity in the distribution of microspheres. One probable explanation for this heterogeneity is clustering of microspheres in the blood vessels.
|
|
| 10. |
- Högberg, Jonas, 1976, et al.
(author)
-
Radiation exposure during liver surgery after treatment with (90)Y microspheres, evaluated with computer simulations and dosimeter measurements.
- 2012
-
In: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 32:4, s. 439-46
-
Journal article (peer-reviewed)abstract
- Purpose. Two patients with liver tumours were planned for a combined treatment, including surgery with preceding injections of β(-) radiation emitting (90)Y microspheres (SIRTEX(®)). The aim of this paper is to present a method of pre-surgical computer simulations of the absorbed dose rate on the surface of tumour tissue, combined with measurements of the actual absorbed dose rate on resected tissue, in order to estimate the absorbed dose to a surgeon's fingers during such surgery procedures. Methods and Materials. The dose rates from β(-) radiation on the surface of tumour tissue were simulated with the software VARSKIN(®)Mod2. The activity concentrations in tumours were estimated, based on SPECT/CT distribution studies of (99m)Tc-MAA and confirmed by SPECT/CT bremsstrahlung studies of (90)Y microspheres. The activity distributions were considered as homogeneous within the tumour regions. The absorbed dose rates at different tumour tissue spots were calculated based on measurements with thermo-luminescent dosimeters (TLD) fastened on resected tissue. Results. The simulations showed a good agreement with the averaged absorbed dose rates based on TLD measurements performed on resected tissue, differing by 13% and 4% respectively. The absorbed dose rates at the measured maximum hotspots were twice as high as the average dose rates for both patients. Conclusion. The data is not sufficient in order to draw any general conclusions about dose rates on tumour tissue during similar surgeries, neither about the influence of dose rate heterogeneities nor about average dose rates. However, the agreement between simulations and measurements on these limited data indicate that this approach is a promising method for estimations of the radiation exposure to the surgeons' fingers during this kind of surgery procedure. More data from similar surgeries are necessary in order to validate the method.
|
|
| 11. |
- Högberg, Jonas, 1976, et al.
(author)
-
Simulation Model of Microsphere Distribution for Selective Internal Radiation Therapy Agrees With Observations
- 2016
-
In: International Journal of Radiation Oncology Biology Physics. - : Elsevier BV. - 0360-3016. ; 96:2, s. 414-421
-
Journal article (peer-reviewed)abstract
- Purpose: To perform a detailed analysis of microsphere distribution in biopsy material from a patient treated with 90 Y-labeled resin spheres and characterize microsphere distribution in the hepatic artery tree, and to construct a novel dichotomous bifurcation model for microsphere deposits and evaluate its accuracy in simulating the observed microsphere deposits. Methods and Materials: Our virtual model consisted of arteries that successively branched into 2 new generations of arteries at 20 nodes. The artery diameter exponentially decreased from the lowest generation to the highest generation. Three variable parameters were optimized to obtain concordance between simulations and measure microsphere distributions: an artery coefficient of variation (ACV) for the diameter of all artery generations and the microsphere flow distribution at the nodes; a hepatic tree distribution volume (HDV) for the artery tree; and an artery diameter reduction (ADR) parameter. The model was tested against previously measured activity concentrations in 84 biopsies from the liver of 1 patient. In 16 of 84 biopsies, the microsphere distribution regarding cluster size and localization in the artery tree was determined via light microscopy of 30-mm sections (mean concentration, 14 microspheres/mg; distributions divided into 3 groups with mean microsphere concentrations of 4.6, 14, and 28 microspheres/mg). Results: Single spheres and small clusters were observed in terminal arterioles, whereas large clusters, up to 450 microspheres, were observed in larger arterioles. For 14 microspheres/mg, the optimized parameter values were ACV = 0.35, HDV = 50 cm(3), and ADR = 6 mu m. For 4.6 microspheres/mg, ACV and ADR decreased to 0.26 and 0 mu m, respectively, whereas HDV increased to 130 cm(3). The opposite trend was observed for 28 microspheres/mg: ACV = 0.49, HDV = 20 cm(3), and ADR = 8 mu m. Conclusion: Simulations and measurements reveal that microsphere clusters are larger and more common in volumes with high microsphere concentrations and indicate that the spatial distribution of the artery tree must be considered in estimates of microsphere distributions.
|
|
| 12. |
- Kaboteh, Reza, et al.
(author)
-
Bone Scan Index: a prognostic imaging biomarker for high-risk prostate cancer patients receiving primary hormonal therapy.
- 2013
-
In: EJNMMI research. - 2191-219X. ; 3:1
-
Journal article (peer-reviewed)abstract
- Background: The objective of this study was to explore the prognostic value of the Bone Scan Index (BSI) obtained at the time of diagnosis in a group of high-risk prostate cancer patients receiving primary hormonal therapy. Methods: This was a retrospective study based on 130 consecutive prostate cancer patients at high risk, based on clinical stage (T2c/T3/T4), Gleason score (8 to 10) and prostate-specific antigen (PSA) (> 20 ng/mL), who had undergone whole-body bone scans < 3 months after diagnosis and who received primary hormonal therapy. BSI was calculated using an automated method. Cox proportional-hazards regression models were used to investigate the association between clinical stage, Gleason score, PSA, BSI and survival. Discrimination between prognostic models was assessed using the concordance index (C-index). Results: In a multivariate analysis, Gleason score (p = 0.01) and BSI (p < 0.001) were associated with survival, but clinical stage (p = 0.29) and PSA (p = 0.57) were not prognostic. The C-index increased from 0.66 to 0.71 when adding BSI to a model including clinical stage, Gleason score and PSA. The 5-year probability of survival was 55% for patients without metastases, 42% for patients with BSI < 1, 31% for patients with BSI = 1 to 5, and 0% for patients with BSI > 5. Conclusions: BSI can be used as a complement to PSA to risk-stratify high-risk prostate cancer patients at the time of diagnosis. This imaging biomarker, reflecting the extent of metastatic disease, can be of value both in clinical trials and in patient management when deciding on treatment.
|
|
| 13. |
- Magnander, Tobias, et al.
(author)
-
A fast GPU code for full Monte Carlo based SPECT reconstruction
- 2016
-
In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer. - 1619-7070 .- 1619-7089.
-
Conference paper (other academic/artistic)abstract
- To improve image quality in SPECT/CT reconstructions, various approximate recovery resolution techniques have been developed and implemented in clinical practice. However, optimal image reconstruction requires accounting for all physical interactions of the emitted photons in the individual patient. The objectives for this study were to develop a novel Monte Carlo (MC) code for fast simulation of individual image projections, and to implement these projections in ordered subset expectation maximum (OSEM) reconstructions of SPECT/CTimages.Method: The MC code was written in Compute Unified Device Architecture language for a computer with four graphic processing units (GeForce GTX Titan X, Nvidia, USA). This enables simulations of parallel photon emission from the voxels matrix (1283 or 2563). Each CT number was converted to attenuation coefficients for photo absorption, coherent scattering and incoherent scattering. The type of interaction was determined by the ratio of attenuation coefficients in the CT voxels. For photon scattering the deflection angle was determined by the differential scattering cross sections. The accepted angle for photon interaction with the crystal was determined from the diameter and height of the collimator hole. Predefined energy and spatial resolution kernels for the crystal were used. TheMCcode was implemented intoOSEMreconstruction of 177Lu, 111In and 99mTc SPECT/CT images. The National Electrical Manufacturers Association (NEMA) image quality phantom was used to evaluate the performance of the MC reconstruction in comparison with clinical standard OSEM reconstructions and clinical state-of-the-art OSEM reconstructions with recovery resolution corrections. Results and conclusion: The performance of the MC code was 500 millions photons/s. The required number of photons emitted per voxel for obtaining low noise in the simulated image was 400 for a 1283 voxel matrix. With this number of emitted photons/voxel the MC-based OSEM reconstruction with 10 subsets was performed within 60 s/iteration. The images converged after 2-4 iterations, depending on the sphere sizes in the NEMAphantom. Thereby, the reconstruction time was <4 minutes. The contrast-to-noise level was slightly improved with increased number of emitted photons/voxel, and the reconstruction time was linearly depending on the number of emitted photons/voxel. The signal-to-background for the spheres in the NEMA phantom was clearly improved with MC-based OSEM reconstruction: e.g. for 177Lu the improvement was 37% compared to standard OSEM and 20 % compared to state-of-the-art OSEM. Furthermore, visual inspection of clinical investigations revealed clearly improved resolution and contrast with MC-based reconstruction.
|
|
| 14. |
- Magnander, Tobias, et al.
(author)
-
A novel statistical analysis method to improve the detection of hepatic foci of (111)In-octreotide in SPECT/CT imaging.
- 2016
-
In: EJNMMI physics. - : Springer Science and Business Media LLC. - 2197-7364. ; 3:1
-
Journal article (peer-reviewed)abstract
- Low uptake ratios, high noise, poor resolution, and low contrast all combine to make the detection of neuroendocrine liver tumours by (111)In-octreotide single photon emission tomography (SPECT) imaging a challenge. The aim of this study was to develop a segmentation analysis method that could improve the accuracy of hepatic neuroendocrine tumour detection.
|
|
| 15. |
|
|
| 16. |
- Magnander, Tobias, et al.
(author)
-
Improved detection rate and visualization of liver uptake foci in diagnostic 111In-octreotide SPECT/CT investigations with a novel segmentation analysis
- 2015
-
In: Optimisation in X-ray and Molecular Imaging 2015 - the Fourth Malmö Conference on Medical Imaging, Gothenburg, Sweden, 28-30 May 2015.
-
Conference paper (other academic/artistic)abstract
- Purpose: Detection of liver tumors will change the course of treatment of neuroendocrine tumours. In nuclear medicine 111In-octreoscan is of high value for detection of neuroendocrine tumours. However, neuroendocrine tumours disseminated to the livers is often challenging to detect from 111In-octreoscan SPECT images due to low uptake, high noise, poor resolution and low contrast. The aim of the present study was to develop a segmentation analysis method for increased diagnostic accuracy of neuroendocrine liver tumours. Methods: For the SPECT reconstruction 120 projections are acquired with 3 degrees spacing around the patient injected with 111In-octreoscan. The projections are reconstructed into a 128x128x128 voxel matrix using OSEM with CT based attenuation correction. The liver is segmented from the SPECT or CT using either an isosurface, region growing or a GPU accelerated level set algorithm. Manual editing finishes the segmentation of the liver. The segmented liver volume of interest, liver VOI, is thresholded at 125 equidistant threshold values between 0 and the maximum voxel value. At each threshold value a connected component labeling algorithm is used to calculate the number of uptake foci (NUF). The normalized NUF (nNUF) is then plotted against the threshold index (ThI), defined as ThI=(cmax-cthr)/cmax, where cmax is the maximal voxel value in the VOI, and cthr is the voxel threshold value. The method is named nNUFTI - normalized Number of Uptake Foci vs ThI. The ThI at 0.25 nNUF was used for analysis of liver tumour involvement. SPECT images from 53 patients without tumour involvement (i.e SPECT negative) in the liver were analysed with nNUFTI. A three year follow up with MRI, SPECT, PET/CT and CT was used to separate the patients into two groups: the healthy group, with still no liver tumours, and the malignant group, shown to have developed tumours in the liver. Results: 40 patients ended up in the healthy group and 13 in the malignant group. The ThI at 0.25 nNUF was significantly different between the groups (p<0.01). A probability function for the ThI values was constructed from the obtained data. This relationship might be a useful guide in the diagnostic decision making. Conclusions: Our new developed method nNUFTI has been shown to perform well. More studies on the nNUFTI method are needed.
|
|
| 17. |
- Magnander, Tobias, et al.
(author)
-
IMPROVED PLANAR KIDNEY ACTIVITY CONCENTRATION ESTIMATE BY THE POSTERIOR VIEW METHOD IN 177LU-DOTATATE TREATMENTS.
- 2016
-
In: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 259-266
-
Journal article (peer-reviewed)abstract
- The aims of this study were to determine how different background regions of interest (ROIs) around the kidney represent true background activity in over- and underlying tissues in(177)Lu-DOTA-octreatate ((177)Lu-DOTATATE) treatments and to determine the influence of the background positions on the kidney activity concentration estimates by the conjugate view (ConjV) and posterior view (PostV) methods. The analysis was performed in single-photon emission computed tomography (SPECT) images of 20 patients, acquired 24 h post injection of a(177)Lu-DOTATATE treatment, by a computer algorithm that created planar images from the SPECT data. The ratio between the activity concentration in the background and the true background varied from 0.36 to 2.08 [coefficient of variation (CV) = 25-181 %] and from 0.44 to 1.52 (CV = 16-70 %) for the right and left kidneys, respectively. The activity concentration estimate in the kidneys was most accurate with the PostV method using a background ROI surrounding the whole kidney, and this combination might be an alternative planar method for improved kidney dosimetry in the(177)Lu-DOTATATE treatments.
|
|
| 18. |
- Ulmert, David, et al.
(author)
-
A novel automated platform for quantifying the extent of skeletal tumour involvement in prostate cancer patients using the bone scan index
- 2012
-
In: European Urology. - : Elsevier BV. - 0302-2838 .- 1873-7560. ; 62:1, s. 78-84
-
Journal article (peer-reviewed)abstract
- Background: There is little consensus on a standard approach to analysing bone scan images. The Bone Scan Index (BSI) is predictive of survival in patients with progressive prostate cancer (PCa), but the popularity of this metric is hampered by the tedium of the manual calculation. Objective: Develop a fully automated method of quantifying the BSI and determining the clinical value of automated BSI measurements beyond conventional clinical and pathologic features. Design, setting, and participants: We conditioned a computer-assisted diagnosis system identifying metastatic lesions on a bone scan to automatically compute BSI measurements. A training group of 795 bone scans was used in the conditioning process. Independent validation of the method used bone scans obtained ≤3 mo from diagnosis of 384 PCa cases in two large population-based cohorts. An experienced analyser (blinded to case identity, prior BSI, and outcome) scored the BSI measurements twice. We measured prediction of outcome using pretreatment Gleason score, clinical stage, and prostate-specific antigen with models that also incorporated either manual or automated BSI measurements. Measurements: The agreement between methods was evaluated using Pearson's correlation coefficient. Discrimination between prognostic models was assessed using the concordance index (C-index). Results and limitations: Manual and automated BSI measurements were strongly correlated (ρ = 0.80), correlated more closely (ρ = 0.93) when excluding cases with BSI scores ≥10 (1.8%), and were independently associated with PCa death (p < 0.0001 for each) when added to the prediction model. Predictive accuracy of the base model (C-index: 0.768; 95% confidence interval [CI], 0.702-0.837) increased to 0.794 (95% CI, 0.727-0.860) by adding manual BSI scoring, and increased to 0.825 (95% CI, 0.754-0.881) by adding automated BSI scoring to the base model. Conclusions: Automated BSI scoring, with its 100% reproducibility, reduces turnaround time, eliminates operator-dependent subjectivity, and provides important clinical information comparable to that of manual BSI scoring. © 2012 European Association of Urology.
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
- Wikberg, Emma, et al.
(author)
-
Evaluation of reconstruction methods and image noise levels concerning visual assessment of simulated liver lesions in In-111-octreotide SPECT imaging
- 2023
-
In: EJNMMI Physics. - 2197-7364. ; 10:1
-
Journal article (peer-reviewed)abstract
- Background: Early cancer detection is crucial for patients' survival. The image quality in In-111-octreotide SPECT imaging could be improved by using Monte Carlo (MC)-based reconstruction. The aim of this observational study was to determine the detection rate of simulated liver lesions for MC-based ordered subset expectation maximization (OSEM) reconstruction compared to conventional attenuation-corrected OSEM reconstruction.MethodsThirty-seven SPECT/CT examinations with In-111-octreotide were randomly selected. The inclusion criterion was no liver lesions at the time of examination and for the following 3 years. SPECT images of spheres representing lesions were simulated using MC. The raw data of the spheres were added to the raw data of the established healthy patients in 26 of the examinations, and the remaining 11 examinations were not modified. The images were reconstructed using conventional OSEM reconstruction with attenuation correction and post filtering (fAC OSEM) and MC-based OSEM reconstruction without and with post filtering (MC OSEM and fMC OSEM, respectively). The images were visually and blindly evaluated by a nuclear medicine specialist. The criteria evaluated were liver lesion yes or no, including coordinates if yes, with confidence level 1-3. The percentage of detected lesions and accuracy (percentage of correctly classified cases), as well as tumor-to-normal tissue concentration (TNC) ratios and signal-to-noise ratios (SNRs), were evaluated.ResultsThe detection rates were 30.8% for fAC OSEM, 42.3% for fMC OSEM, and 50.0% for MC OSEM. The accuracies were 45.9% for fAC OSEM, 45.9% for fMC OSEM, and 54.1% for MC OSEM. The number of false positives was higher for fMC and MC OSEM. The observer's confidence level was higher in filtered images than in unfiltered images. TNC ratios were significantly higher, statistically, with MC OSEM and fMC OSEM than with AC OSEM, but SNRs were similar due to higher noise with MC OSEM.ConclusionOne in two lesions were found using MC OSEM versus one in three using conventional reconstruction. TNC ratios were significantly improved, statistically, using MC-based reconstruction, but the noise levels increased and consequently the confidence level of the observer decreased. For further improvements, image noise needs to be suppressed.
|
|
| 22. |
- Gjertsson, Peter, 1961, et al.
(author)
-
Diagnostic and referral delay in patients with aortic stenosis is common and negatively affects outcome
- 2007
-
In: Scand Cardiovasc J. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 41:1, s. 12-8
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: Aortic stenosis (AS) patients are often severely symptomatic at the time of aortic valve replacement (AVR). We wanted to investigate doctors' delay and its impact on outcome. DESIGN: AS patients undergoing AVR (n = 422) were included. Clinical and echocardiographic data at the time of diagnosis and preoperatively were noted. The risk of death after AVR was estimated using Poisson regression, incorporating age, gender, coronary artery disease, NYHA III/IV and time on the waiting list for AVR. RESULTS: The age (mean+/-SD) was 71+/-8.6 years, 45% were women, and 48% were in NYHA III/IV. 55% underwent AVR within one year of diagnosis, indicating late diagnosis. The time from referral to AVR (median, range) was 112 (1-803) days. NYHA III/IV independently predicted mortality (hazard ratio 1.76, 95% CI 1.28-2.43, p = 0.0005). The time from referral to AVR influenced the risk of death immediately after operation (p = 0.0083). CONCLUSION: Late diagnosis and late referral for AVR are common, and negatively influence outcome in patients with AS. Delay in surgery after referral increase the mortality immediately after AVR.
|
|
| 23. |
- Gjertsson, Peter, 1961, et al.
(author)
-
Left ventricular diastolic dysfunction late after aortic valve replacement in patients with aortic stenosis
- 2005
-
In: Am J Cardiol. - : Elsevier BV. - 0002-9149. ; 96:5, s. 722-7
-
Journal article (peer-reviewed)abstract
- Patients with severe aortic stenosis (AS) are known to have increased left ventricular (LV) mass and diastolic dysfunction. It has been suggested that LV mass and diastolic function normalize after aortic valve replacement (AVR). In the present study, change in LV mass index and diastolic function 10 years after AVR for AS was evaluated. Patients who underwent AVR from 1991 to 1993 (n = 57; mean age 67 +/- 8.6 years at AVR, 58% men) were investigated with Doppler echocardiography preoperatively and 2 and 10 years postoperatively. Diastolic function was evaluated by integrating mitral and pulmonary venous flow data. Expected values for each patient, taking age into consideration, were defined using a control group (n = 71; age range 18 to 83 years). Patients were classified into 4 types: normal diastolic function (type A), mild diastolic dysfunction (type B), moderate diastolic dysfunction (type C), and severe diastolic dysfunction (type D). There was a reduction in LV mass index between the preoperative (161 +/- 39 g/m2) and 2-year follow-up (114 +/- 28 g/m2) examinations (p <0.0001), but no further reduction was seen at 10 years (119 +/- 49 g/m2). The percentage of patients with increased LV mass index decreased from 83% preoperatively to 29% at 2-year follow-up (p <0.001). The percentage of patients with moderate to severe LV diastolic dysfunction (types C and D) was unchanged between the preoperative (7%) and 2-year follow-up (13%) examinations (p = 0.27). The percentage of patients increased at 10-year follow-up to 61% (p <0.0001). In conclusion, this reveals the development of moderate to severe diastolic dysfunction 10 years after AVR, despite a reduction in the LV mass index.
|
|
| 24. |
- Gjertsson, Peter, 1961, et al.
(author)
-
Preoperative moderate to severe diastolic dysfunction: a novel Doppler echocardiographic long-term prognostic factor in patients with severe aortic stenosis
- 2005
-
In: J Thorac Cardiovasc Surg. - : Elsevier BV. - 0022-5223. ; 129:4, s. 890-6
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: We studied long-term outcomes in severe aortic stenosis and the importance of prosthesis type (mechanical vs biologic) and size, preoperative left ventricular ejection fraction, diastolic function, and left ventricular mass. METHODS: Patients undergoing valve replacement from 1991 to 1993 (n = 399, 45% women) were included. The diastolic function was evaluated by integrating mitral and pulmonary venous flow data with Doppler echocardiography. The patients were classified as having either normal diastolic function to mild diastolic dysfunction or moderate to severe diastolic dysfunction. Left ventricular ejection fraction and the diastolic function category were incorporated together with age, sex, and time since operation into a Poisson regression model with death as the end point. Prosthesis type and size and left ventricular mass were also investigated. RESULTS: The age (mean +/- SD) was 71 +/- 9 years, and the overall survival after 12 years was 50%. Although markedly reduced during the initial 6-month period, mortality risk subsequently increased more than could be explained by age (hazard ratio of 1-year difference = 1.12, P = .0005). The moderate to severe diastolic dysfunction pattern independently predicted late mortality (hazard ratio = 1.72, P = .0038), whereas left ventricular ejection fraction did not (hazard ratio = 0.99, P = .18). The prognostic importance of moderate to severe diastolic dysfunction did not diminish with time; on the contrary, it tended to increase. Mortality after 12 years was not predicted by left ventricular mass (P = .66), prosthesis type (P = .57), or prosthesis size (P = .58). CONCLUSION: This study reveals that moderate to severe diastolic dysfunction in patients with aortic stenosis is an independent predictor of late mortality after valve replacement and that its importance does not decrease with time. Our findings may suggest that moderate to severe diastolic dysfunction implies nonreversible myocardial changes that negatively affect survival.
|
|
| 25. |
|
|
| 26. |
- Kaboteh, Reza, et al.
(author)
-
Progression of bone metastases in patients with prostate cancer - automated detection of new lesions and calculation of bone scan index
- 2013
-
In: EJNMMI Research. - 2191-219X. ; 3:1
-
Journal article (peer-reviewed)abstract
- BACKGROUND: The objective of this study was firstly to develop and evaluate an automated method for the detection of new lesions and changes in bone scan index (BSI) in serial bone scans and secondly to evaluate the prognostic value of the method in a group of patients receiving chemotherapy.METHODS: The automated method for detection of new lesions was evaluated in a group of 266 patients using the classifications by three experienced bone scan readers as a gold standard. The prognostic value of the method was assessed in a group of 31 metastatic hormone-refractory prostate cancer patients who were receiving docetaxel. Cox proportional hazards were used to investigate the association between percentage change in BSI, number of new lesions and overall survival. Kaplan-Meier estimates of the survival function were used to indicate a significant difference between patients with an increase/decrease in BSI or those with two or more new lesions or less than two new lesions.RESULTS: The automated method detected progression defined as two or more new lesions with a sensitivity of 93% and a specificity of 87%. In the treatment group, both BSI changes and the number of new metastases were significantly associated with survival. Two-year survival for patients with increasing and decreasing BSI from baseline to follow-up scans were 18% and 57% (p = 0.03), respectively. Two-year survival for patients fulfilling and not fulfilling the criterion of two or more new lesions was 35% and 38% (n.s.), respectively.CONCLUSIONS: An automated method can be used to calculate the number of new lesions and changes in BSI in serial bone scans. These imaging biomarkers contained prognostic information in a small group of patients with prostate cancer receiving chemotherapy.
|
|
| 27. |
- Levren, Gabriella, et al.
(author)
-
Relation between pain and skeletal metastasis in patients with prostate or breast cancer
- 2011
-
In: Clinical Physiology and Functional Imaging. - 1475-0961. ; 31:3, s. 193-195
-
Journal article (peer-reviewed)abstract
- The aim of this study was to examine the relation between pain and bone metastases in a group of patients with prostate or breast cancer that had been referred for bone scintigraphy. Whole-body bone scans, anterior and posterior views obtained with a dual detector gamma camera were studied from 101 consecutive patients who had undergone scintigraphy (600 MBq Tc-99m MDP) because of suspected bone metastatic disease. At the time of the examination, all patients were asked whether they felt any pain or had recently a trauma. This information was correlated with the classifications regarding the presence or absence of bone metastases made by a group of three experienced physicians. In patients with prostate cancer, we found metastases in 47% (18/38) of the patients with pain, but only in 12% (2/17) of the patients without pain (p = 0·01). In patients with breast cancer, on the other hand, metastases were more common in patients without pain (71%; 10/14) than in patients with pain (34%; 11/32) (p = 0·02). In conclusion, a significant relation between pain and skeletal metastases could be found in patients with prostate cancer and a reverse relation in patients with breast cancer.
|
|
| 28. |
- Polte, Christian Lars, et al.
(author)
-
Cardiac Positron Emission Tomography: a Clinical Perspective
- 2016
-
In: Current Cardiovascular Imaging Reports. - : Springer Science and Business Media LLC. - 1941-9066 .- 1941-9074. ; 9:3
-
Journal article (peer-reviewed)abstract
- © 2016, Springer Science+Business Media New York. Cardiac positron emission tomography is a powerful, quantitative, non-invasive imaging modality, which adds valuable diagnostic and prognostic information to the clinical work-up. Myocardial perfusion and viability imaging are, as a result of continuously growing evidence, established clinical indications that may be cost-effective, due to the high diagnostic accuracy of cardiac positron emission tomography, despite high single-test costs. In the field of inflammation imaging, new indications are entering the clinical arena, which may contribute to a better diagnosis and overall patient care, as for instance in patients with cardiac sarcoidosis, prosthetic valve endocarditis and cardiac device infections. This review will discuss the individual strengths and weaknesses of cardiac positron emission tomography and, hence, the resulting clinical usefulness based on the current evidence for an individualized, patient-centered imaging approach.
|
|
| 29. |
- Tjörnstrand, Axel, et al.
(author)
-
Lower 68 Ga-DOTATOC Uptake in Non-Functioning Pituitary Neuroendocrine Tumors Compared to Normal Pituitary Gland - a Proof-of-Concept Study.
- 2020
-
In: Clinical Endocrinology. - : Wiley. - 0300-0664 .- 1365-2265. ; 92:3, s. 222-231
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: 68 Ga-DOTATOC PET targets somatostatin receptors (SSTRs) and is well established for the detection of SSTR-expressing tumors, such as gastrointestinal neuroendocrine tumors. Pituitary adenomas, recently designated as pituitary neuroendocrine tumors (PitNETs), also express SSTRs, but there has been no previous evaluations of 68 Ga-DOTATOC PET in PitNET patients. The aim of this pilot study was to evaluate the diagnostic properties of 68 Ga-DOTATOC PET in the most common PitNET, i.e. non-functioning (NF)-PitNET.DESIGN/METHODS: NF-PitNET patients (n = 9) and controls (n = 13) were examined preoperatively with 68 Ga-DOTATOC PET for 45 min after tracer injection in dynamic list mode. Tumor specimens were collected during surgery in patients. MRI and PET images were co-registered using PMOD software. The maximum standard uptake value (SUVmax ) was analyzed in manually outlined regions of interest (ROC) around the tumor in patients and around the pituitary gland in controls. Immunohistochemical analyses were conducted on tumor specimens for assessment of tumor cell type and SSTR expression.RESULTS: Median SUVmax (IQR) was lower in patients than in controls (3.9 [3.4-8.5] vs 14.1 [12.5-15.9]; P < .01]. In ROC analysis, the area under the curve was 0.87 (P < .01) for SUVmax , with 78% sensitivity and 92% specificity. Immunohistochemical analysis showed NF-PitNETs were of gonadotroph (n = 7) and corticotroph (n = 2) origin. SSTR expression was high for SSTR3, low-to-moderate for SSTR2, and low for SSTR1 and SSTR5.CONCLUSIONS: This proof-of-concept study shows that 68 Ga-DOTATOC PET can be used to differentiate between normal pituitary tissue and NF-PitNET.
|
|
| 30. |
- Tjörnstrand, Axel, et al.
(author)
-
Pre- and postoperative Ga-68-DOTATOC positron emission tomography for hormone-secreting pituitary neuroendocrine tumours
- 2021
-
In: Clinical Endocrinology. - : John Wiley & Sons. - 0300-0664 .- 1365-2265. ; 94:6, s. 956-967
-
Journal article (peer-reviewed)abstract
- Objectives Somatostatin receptors (SSTRs) are potential targets for detecting pituitary neuroendocrine tumours (PitNETs) that can be visualized effectively with Ga-68-labelled PET tracers. With this study, we have evaluated the diagnostic properties of such a tracer, Ga-68-DOTATOC, in patients with hormone-producing PitNETs before and after surgery. Design/Methods This prospective case-control study presents preoperative positron emission tomography (PET) and histopathological data in 18 patients with somatotroph (n = 8), corticotroph (n = 7) and thyrotroph (n = 3) PitNETs. Patients were scanned pre- and postoperatively with Ga-68-DOTATOC PET. For the postoperative part of the study, patients with gonadotroph tumours (n = 7) were also included. Fifteen pituitary healthy controls underwent the same protocol once. The maximum standard uptake value (SUVmax) was analysed in manually outlined regions around the tumour in patients and around the pituitary gland in controls. specimens were collected during surgery in subjects for assessment of adenohypophyseal tumour cell type and the SSTR expression. Results Thyrotroph tumours showed higher uptake (median SUVmax 41.1; IQR 37.4-60.0) and corticotroph tumours lower uptake (SUVmax 6.8; 2.6-9.3) than normal pituitary gland (SUVmax 13.8; 12.1-15.5). The uptake in somatotroph tumours (SUVmax 15.9; 11.6-19.7) was similar to the uptake in the pituitary gland. There was a strong correlation between SUVmax and SSTR2 expression (r = .75 (P < .01)). In the postoperative evaluation, PET was able to correlate tracer uptake with biochemical cure and noncure in patients with an abnormal postoperative magnetic resonance image and a preoperative tumour uptake SUVmax > 13.8. Conclusions Ga-68-DOTATOC PET can be used to detect thyrotroph tumours in the pre- and postoperative imaging assessment. Corticotroph tumours had a significantly lower uptake compared to the pituitary gland but without a distinct increased tumour uptake the clinical postoperative value is limited.
|
|
| 31. |
- Waldenström, Ann-Charlotte, 1950, et al.
(author)
-
A comparison of two imaging modalities for detecting lymphatic nodal spread in radiochemotherapy of locally advanced cervical cancer
- 2018
-
In: Physics and Imaging in Radiation Oncology. - : Elsevier BV. - 2405-6316. ; 8, s. 33-37
-
Journal article (peer-reviewed)abstract
- Background and purpose: In uterine cervical cancer tumour spread reaching the para-aortic lymph nodes is the most significant independent pre-treatment predictor of progression-free survival. When introducing [18F] fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) in our clinic for patients with advanced cervical cancer planned for definitive radiochemotherapy, the purpose of this study was to quantify to what extent the added information lead to changes in radiotherapy planning. Material and methods: We included 25 consecutive patients with cervical cancer stages IB2 – IIIB planned for definitive radiochemotherapy between November 2010 and May 2012. The patients were examined both with magnetic resonance imaging (MRI) and FDG-PET/CT before treatment and after four weeks of treatment. Results: In 11/24 (46%) of the patients the FDG-PET/CT before treatment provided additional diagnostic information leading to changes in treatment planning compared to information from MRI. Seven of these eleven patients (64%) were alive and without evidence of disease at four-year follow-up. The MRI detected pelvic tumour spread not seen on the FDG-PET/CT in 2/24 patients. The disease-free four-year survival was 59%. Conclusions: Additional diagnostic information from FDG-PET/CT changed treatment strategy in almost half of the patients and may have increased chances of survival in this limited group of patients with locally advanced uterine cervical cancer. We recommend both modalities for nodal detection.
|
|
