| 1. |
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| 2. |
- Abrahamsson, Johan, et al.
(författare)
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Complete metabolic response with [18F]fluorodeoxyglucose-positron emission tomography/computed tomography predicts survival following induction chemotherapy and radical cystectomy in clinically lymph node positive bladder cancer
- 2022
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Ingår i: BJU International. - : Wiley. - 1464-4096 .- 1464-410X. ; 129:2, s. 174-181
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To determine whether repeated [18F]fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET-CT) scans can predict increased cancer-specific survival (CSS) after induction chemotherapy followed by radical cystectomy (RC). Patients and Methods: Between 2007 and 2018, 86 patients with clinically lymph node (LN)-positive bladder cancer (T1–T4, N1–N3, M0–M1a) were included and underwent a repeated FDG-PET-CT during cisplatin-based induction chemotherapy. The 71 patients that had a response to chemotherapy underwent RC. Response to chemotherapy was evaluated in LNs through repeated FDG-PET-CT and stratified as partial response or complete response using three different methods: maximum standardised uptake value (SUVmax), adapted Deauville criteria, and total lesion glycolysis (TLG). Progression-free survival (PFS) and CSS were analysed for all three methods by Cox regression analysis. Results: After a median follow-up of 40 months, 15 of the 71 patients who underwent RC had died from bladder cancer. Using SUVmax and the adapted Deauville criteria, multivariable Cox regression analyses adjusting for age, clinical tumour stage and LN stage showed that complete response was associated with increased PFS (hazard ratio [HR] 3.42, 95% confidence interval [CI] 1.20–9.77) and CSS (HR 3.30, 95% CI 1.02–10.65). Using TLG, a complete response was also associated with increased PFS (HR 5.17, 95% CI 1.90–14.04) and CSS (HR 6.32, 95% CI 2.06–19.41). Conclusions: Complete metabolic response with FDG-PET-CT predicts survival after induction chemotherapy followed by RC in patients with LN-positive bladder cancer and comprises a novel tool in evaluating response to chemotherapy before surgery. This strategy has the potential to tailor treatment in individual patients by identifying significant response to chemotherapy, which motivates the administration of a full course of induction chemotherapy with a higher threshold for suspending treatment due to toxicity and side-effects.
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| 3. |
- Almquist, Helén
(författare)
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Attenuation correction in pulmonary and myocardial single photon emission computed tomography.
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective was to develop and validate methods for single photon emission computed tomography, SPECT, allowing quantitative physiological and diagnostic studies of lung and heart. A method for correction of variable attenuation in SPECT, based on transmission measurements before administration of an isotope to the subject, was developed and evaluated. A protocol based upon geometrically well defined phantoms was developed. In a mosaic pattern phantom count rates were corrected from 39-43% to 101-110% of reference. In healthy subjects non-gravitational pulmonary perfusion gradients, observed without attenuation correction were artefacts caused by attenuation. Pulmonary density in centre of right lung, obtained from the transmission measurement, was 0.28 ± 0.03 g ml-1 in normal subjects. Mean density was lower in large lungs compared to smaller ones. We also showed that regional ventilation/perfusion ratios could be measured with SPECT, using the readily available tracer 133Xe. Because of the low energy of 133Xe this relies heavily upon attenuation correction. A commercially available system for attenuation correction with simultaneous emission and transmission, considered to improve myocardial SPECT, performed erroneously. This could lead to clinical misjudgement. We considered that manufacturer-independent pre-clinical tests are required. In a test of two other commercial systems, based on different principles, an adapted variant of our initial protocol was proven useful. Only one the systems provided corrected emission count rates independently on phantom configuration. Errors in the other system were related to inadequate compensation of the influence of emission activity on the transmission study.
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| 4. |
- Almquist, Helén, et al.
(författare)
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Quantitative SPECT by attenuation correction of the projection set using transmission data: evaluation of a method
- 1990
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Ingår i: European Journal Of Nuclear Medicine. - 1432-105X. ; 16:8-10, s. 587-594
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Tidskriftsartikel (refereegranskat)abstract
- A method for measuring attenuation coefficients in single-photon emission tomography (SPECT) is described and evaluated, together with a method for attenuation correction using these measured attenuation coefficients. Build-up, caused by scattered photons, is corrected for by a simple substitution in the algorithms. Transmission studies are performed with a 99mTc- or 57Co flood source, and emission phantom studies with 99mTc line sources. The method is evaluated with variable but well-defined phantoms. The result is accurate attenuation coefficients for different densities, dimensions and geometries, and an accuracy of corrected emission activities of better than +/- 10% in most cases. The present limitations of the method for attenuation correction are discussed.
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| 5. |
- Barrington, Sally F., et al.
(författare)
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Concordance between four European centres of PET reporting criteria designed for use in multicentre trials in Hodgkin lymphoma
- 2010
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 37:10, s. 1824-1833
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Tidskriftsartikel (refereegranskat)abstract
- To determine if PET reporting criteria for the Response Adapted Treatment in Hodgkin Lymphoma (RATHL) trial could enable satisfactory agreement to be reached between 'core' laboratories operating in different countries. Four centres reported scans from 50 patients with stage II-IV HL, acquired before and after two cycles of Adriamycin/bleomycin/vinblastine/dacarbazine. A five-point scale was used to score response scans using 'normal' mediastinum and liver as reference levels. Centres read scans independently of each other. The level of agreement between centres was determined assuming (1) that uptake in sites involved at diagnosis that was higher than liver uptake represented disease (conservative reading), and (2) that uptake in sites involved at diagnosis that was higher than mediastinal uptake represented disease (sensitive reading). There was agreement that the response scan was 'positive' or 'negative' for lymphoma in 44 patients with a conservative reading and in 41 patients with a sensitive reading. Kappa was 0.85 (95% CI 0.74-0.96) for conservative reading and 0.79 (95% CI 0.67-0.90) for sensitive reading. Agreement was reached in 46 and 44 patients after discussion for the conservative and sensitive readings, respectively. The criteria developed for reporting in the RATHL trial are sufficiently robust to be used in a multicentre setting.
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| 6. |
- Barrington, Sally F, et al.
(författare)
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PET-CT for staging and early response : results from the Response-Adapted Therapy in Advanced Hodgkin Lymphoma study.
- 2016
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 127:12, s. 1531-1538
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Tidskriftsartikel (refereegranskat)abstract
- International guidelines recommend that positron emission tomography-computed tomography (PET-CT) should replace CT in Hodgkin lymphoma (HL). The aims of this study were to compare PET-CT with CT for staging and measure agreement between expert and local readers, using a 5-point scale (Deauville criteria), to adapt treatment in a clinical trial: Response-Adapted Therapy in Advanced Hodgkin Lymphoma (RATHL). Patients were staged using clinical assessment, CT, and bone marrow biopsy (RATHL stage). PET-CT was performed at baseline (PET0) and after 2 chemotherapy cycles (PET2) in a response-adapted design. PET-CT was reported centrally by experts at 5 national core laboratories. Local readers optionally scored PET2 scans. The RATHL and PET-CT stages were compared. Agreement among experts and between expert and local readers was measured. RATHL and PET0 stage were concordant in 938 (80%) patients. PET-CT upstaged 159 (14%) and downstaged 74 (6%) patients. Upstaging by extranodal disease in bone marrow (92), lung (11), or multiple sites (12) on PET-CT accounted for most discrepancies. Follow-up of discrepant findings confirmed the PET characterization of lesions in the vast majority. Five patients were upstaged by marrow biopsy and 7 by contrast-enhanced CT in the bowel and/or liver or spleen. PET2 agreement among experts (140 scans) with a κ (95% confidence interval) of 0.84 (0.76-0.91) was very good and between experts and local readers (300 scans) at 0.77 (0.68-0.86) was good. These results confirm PET-CT as the modern standard for staging HL and that response assessment using Deauville criteria is robust, enabling translation of RATHL results into clinical practice.
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| 7. |
- Bjöersdorff, Mimmi, et al.
(författare)
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Impact of penalizing factor in a block-sequential regularized expectation maximization reconstruction algorithm for 18 F-fluorocholine PET-CT regarding image quality and interpretation
- 2019
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Ingår i: EJNMMI Physics. - : Springer Science and Business Media LLC. - 2197-7364. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recently, the block-sequential regularized expectation maximization (BSREM) reconstruction algorithm was commercially introduced (Q.Clear, GE Healthcare, Milwaukee, WI, USA). However, the combination of noise-penalizing factor (β), acquisition time, and administered activity for optimal image quality has not been established for 18 F-fluorocholine (FCH). The aim was to compare image quality and diagnostic performance of different reconstruction protocols for patients with prostate cancer being examined with 18 F-FCH on a silicon photomultiplier-based PET-CT. Thirteen patients were included, injected with 4 MBq/kg, and images were acquired after 1 h. Images were reconstructed with frame durations of 1.0, 1.5, and 2.0 min using β of 150, 200, 300, 400, 500, and 550. An ordered subset expectation maximization (OSEM) reconstruction with a frame duration of 2.0 min was used for comparison. Images were quantitatively analyzed regarding standardized uptake values (SUV) in metastatic lymph nodes, local background, and muscle to obtain contrast-to-noise ratios (CNR) as well as the noise level in muscle. Images were analyzed regarding image quality and number of metastatic lymph nodes by two nuclear medicine physicians. Results: The highest median CNR was found for BSREM with a β of 300 and a frame duration of 2.0 min. The OSEM reconstruction had the lowest median CNR. Both the noise level and lesion SUV max decreased with increasing β. For a frame duration of 1.5 min, the median quality score was highest for β 400-500, and for a frame duration of 2.0 min the score was highest for β 300-500. There was no statistically significant difference in the number of suspected lymph node metastases between the different image series for one of the physicians, and for the other physician the number of lymph nodes differed only for one combination of image series. Conclusions: To achieve acceptable image quality at 4 MBq/kg 18 F-FCH, we propose using a β of 400-550 with a frame duration of 1.5 min. The lower β should be used if a high CNR is desired and the higher if a low noise level is important.
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| 8. |
- Johansson Kollberg, Petter, et al.
(författare)
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[18F]Fluorodeoxyglucose-positron emission tomography/computed tomography response evaluation can predict histological response at surgery after induction chemotherapy for oligometastatic bladder cancer
- 2017
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Ingår i: Scandinavian Journal of Urology. - : Medical Journals Sweden AB. - 2168-1805 .- 2168-1813. ; 51:4, s. 308-313
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Patients with limited metastatic and locally advanced bladder cancer have a poor prognosis, and no definite treatment recommendations exist. However, long-term survival is possible for selected patients if surgery is combined with multiple courses of chemotherapy (i.e. induction chemotherapy). Patients with tumours that are insensitive to chemotherapy probably have little to gain from subsequent extensive surgery. The aim of this study was to evaluate sequential FDG-PET/CT examinations as an indicator of chemotherapy response. Materials and methods: Between 2007 and 2015, 50 patients with oligometastatic invasive bladder cancer selected for induction chemotherapy underwent two FDG-PET/CT examinations: the first before the start of chemotherapy and the second after three courses of cisplatinum-based combination chemotherapy. Responders were given up to six courses of chemotherapy. FDG-PET/CT response was correlated with histological response in excised lymph-node metastases. Results: Three patients showed progression to incurable disease during chemotherapy and another two patients did not undergo surgery, for medical reasons. Lymphadenectomy was performed in the remaining 45 patients, of whom 43 had lymph-node metastasis. FDG-PET/CT prediction of the histological nodal chemotherapy response was correct in 37 (86%) of those 43. The second FDG-PET/CT examination identified four out of nine non-responders. For response, the sensitivity, specificity, and positive and negative predictive values for FDG-PET/CT accuracy were 37 out of 37 (100%), one out of six (17%), 37 out of 42 (88%) and one out of one (100%), respectively. Conclusions: Repeated FDG-PET/CT seems to predict histological response. However, with the histological response criteria used in this study, five non-responders were not identified by the second FDG-PET/CT investigation.
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| 9. |
- Kjölhede, Henrik, et al.
(författare)
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(18)F-choline PET/CT for early detection of metastases in biochemical recurrence following radical prostatectomy.
- 2015
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Ingår i: World Journal of Urology. - : Springer Science and Business Media LLC. - 1433-8726 .- 0724-4983. ; 33:11, s. 1749-1752
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Tidskriftsartikel (refereegranskat)abstract
- Salvage radiotherapy (SRT) for biochemical recurrence (BCR) following radical prostatectomy (RP) should if possible be added at a prostate-specific antigen (PSA) level of <1-2 ng/mL. The value of positron emission tomography combined with computed tomography (PET/CT) at such low PSA values is not defined. The purpose was to determine what proportion of a well-defined cohort of hormone-naïve patients who were candidates for early salvage radiotherapy had (18)F-choline PET/CT findings suggesting metastases.
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| 10. |
- Kjölhede, Henrik, et al.
(författare)
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Combined (18) F-fluorocholine and (18) F-fluoride positron emission tomography/computed tomography imaging for staging of high-risk prostate cancer.
- 2012
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Ingår i: BJU International. - 1464-4096. ; 110:10, s. 1501-1506
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Tidskriftsartikel (refereegranskat)abstract
- Study Type - Diagnosis (cohort) Level of Evidence 2a What's known on the subject? and What does the study add? Positron emission tomography/computed tomography (PET/CT) with choline and fluoride for the detection of metastases in patients with prostate cancer have each been evaluated, with mixed results. Choline PET/CT has been evaluated against pelvic lymphadenectomy, generally with a low sensitivity but a high specificity; however, the study populations have been heterogenous. Fluoride PET/CT has been evaluated against other imaging methods, such as bone scan, single photon emission CT and MRI, and has been shown to have high specificity as well as sensitivity for bone metastases, but there are no studies with biopsy verification. This is the first study that evaluates the clinical use of both choline and fluoride PET/CT on the same patients in a well-defined population of patients with high-risk prostate cancer. OBJECTIVE: • To investigate how often positron emission tomography/computed tomography (PET/CT) scans, with both (18) F-fluorocholine and (18) F-fluoride as markers, add clinically relevant information for patients with prostate cancer who have high-risk tumours and a normal or inconclusive planar bone scan. PATIENTS AND METHODS: • Patients with prostate cancer with prostate specific antigen (PSA) levels between 20 and 99 ng/mL and/or Gleason score 8-10 tumours, planned for treatment with curative intent based on routine staging with a negative or inconclusive bone scan, were further investigated with a (18) F-fluorocholine and a (18) F-fluoride PET/CT. • None of the patients received hormonal therapy before the staging procedures were completed. RESULTS: • For 50 of the 90 included patients (56%) one or both PET/CT scans indicated metastases. • (18) F-fluorocholine PET/CT indicated lymph node metastases and/or bone metastases in 35 patients (39%). • (18) F-fluoride PET/CT was suggestive for bone metastases in 37 patients (41%). • In 18 patients (20%) the PET/CT scans indicated widespread metastases, leading to a change in therapy intent from curative to non-curative. • Of the patients with positive scans, 74% had Gleason score 8-10 tumours. Of the patients with Gleason score 8-10 tumours, 64% had positive scans. CONCLUSIONS: • PET/CT scans with (18) F-fluorocholine and (18) F-fluoride commonly detect metastases in patients with high-risk prostate cancer and a negative or inconclusive bone scan. • For 20% of the patients the results of the PET/CT scans changed the treatment plan.
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