Peter Iversen

Dr. Peter Iversen

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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 November 2021 in EJNMMI Physics
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PSPeter Frøhlich Staanum
Peter Frøhlich Staanum
AFAnders Floor Frellsen
Anders Floor Frellsen
MOMarie Louise Olesen
Marie Louise Olesen
PIPeter Iversen
Peter Iversen
AAAnne Kirstine Arveschoug
Anne Kirstine Arveschoug
Background: Kidney dosimetry after peptide receptor radionuclide therapy using 177Lu-labelled somatostatin analogues is a procedure with multiple steps. We present the SPECT/CT-based implementation at Aarhus University Hospital and evaluate the uncertainty of the various steps in order to estimate the total uncertainty and to identify the major sources of uncertainty. Absorbed dose data from 115 treatment fractions are reported. Results: The total absorbed dose with uncertainty is presented for 59 treatments with [177Lu]Lu-DOTATOC and 56 treatments with [177Lu]Lu-DOTATATE. For [177Lu]Lu-DOTATOC the mean and median specific absorbed dose (dose per injected activity) is 0.37 Gy/GBq and 0.38 Gy/GBq, respectively, while for [177Lu]Lu-DOTATATE the median and mean are 0.47 Gy/GBq and 0.46 Gy/GBq, respectively. The uncertainty of the procedure is estimated to be about 13% for a single treatment fraction, where the absorbed dose calculation is based on three SPECT/CT scans 1, 4 and 7 days post-injection, while it increases to about 19% if only a single SPECT/CT scan is performed 1 day post-injection. Conclusions: The specific absorbed dose values obtained with the described procedure are comparable to those from other treatment sites for both [177Lu]Lu-DOTATOC and [177Lu]Lu-DOTATATE, but towards the lower end of the range of reported values. The estimated uncertainty is also comparable to that from other reports and judged acceptable for clinical and research use, thus proving the kidney dosimetry procedure a useful tool. The greatest reduction in uncertainty can be obtained by improved activity determination, partial volume correction and additional SPECT/CT scans.

1 September 2016 in Clinical Epidemiology
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John Thomas HelgstrandJohn Thomas Helgstrand
John Thomas Helgstrand
NKNina Klemann
Nina Klemann
Martin Andreas RøderMartin Andreas Røder
Martin Andreas Røder
BTBirgitte G. Toft
Birgitte G. Toft
KBKlaus Brasso
Klaus Brasso
PIPeter Iversen
Peter Iversen
Background: Systematized Nomenclature of Medicine (SNOMED) codes are computer-processable medical terms used to describe histopathological evaluations. SNOMED codes are not readily usable for analysis. We invented an algorithm that converts prostate SNOMED codes into an analyzable format. We present the methodology and early results from a new national Danish prostate database containing clinical data from all males who had evaluation of prostate tissue from 1995 to 2011. Materials and methods: SNOMED codes were retrieved from the Danish Pathology Register. A total of 26,295 combinations of SNOMED codes were identified. A computer algorithm was developed to transcode SNOMED codes into an analyzable format including procedure (eg, biopsy, transurethral resection, etc), diagnosis, and date of diagnosis. For validation, ~55,000 pathological reports were manually reviewed. Prostate-specific antigen, vital status, causes of death, and tumor-node-metastasis classification were integrated from national registries. Results: Of the 161,525 specimens from 113,801 males identified, 83,379 (51.6%) were sets of prostate biopsies, 56,118 (34.7%) were transurethral/transvesical resections of the prostate (TUR-Ps), and the remaining 22,028 (13.6%) specimens were derived from radical prostatectomies, bladder interventions, etc. A total of 48,078 (42.2%) males had histopathologically verified prostate cancer, and of these, 78.8% and 16.8% were diagnosed on prostate biopsies and TUR-Ps, respectively. Future perspectives: A validated algorithm was successfully developed to convert complex prostate SNOMED codes into clinical useful data. A unique database, including males with both normal and cancerous histopathological data, was created to form the most comprehensive national prostate database to date. Potentially, our algorithm can be used for conversion of other SNOMED data and is available upon request.

2 December 2016 in Acta Oncologica
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Journal Article
Open access
SLSigne Benzon Larsen
Signe Benzon Larsen
KBKlaus Brasso
Klaus Brasso
JCJane Christensen
Jane Christensen
CJChristoffer Johansen
Christoffer Johansen
ATAnne Marie Tjønneland
Anne Marie Tjønneland
SDSusanne Oksbjerg Dalton
Susanne Oksbjerg Dalton
Introduction: Men with low socioeconomic position experience higher mortality after a prostate cancer diagnosis compared to men with a higher socioeconomic position, however, the specific mediators of this association are unclear. We therefore evaluated the influence of potential mediators on the association between socioeconomic position, and prostate cancer-specific and all-cause death in prostate cancer patients. Materials and methods: We conducted a cohort study of prostate cancer patients in the Danish Diet, Cancer and Health study. All patients completed questionnaires and anthropometric measurements at enrollment. Information on educational level, income, comorbidity and vital status was obtained by linkage to Danish nationwide registries. Clinical data and anthropometric measures were collected from medical records at diagnosis. Cox proportional hazard models were used to compute hazard ratios (HR) for all-cause and prostate cancer-specific death according to socioeconomic position and potential mediators. Results: We included 953 prostate cancer patients identified among 27 179 male participants in the Diet, Cancer and Health study who were followed for a median of 6.5 years (interquartile range 6.4–11.2 years). Patients with low socioeconomic position were more often overweight or obese at baseline. Low socioeconomic position was associated with increased prostate cancer-specific and all-cause death. The increased mortality could largely be explained by tumor aggressiveness, comorbidity, treatment and metabolic indicators, except for patients in the lowest income group. Discussion: Our study confirmed the a priori assumption that socioeconomic position is associated with increased mortality after prostate cancer. The increased mortality could largely be explained by lifestyle and clinical parameters.

22 March 2011 in APMIS
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KBKasper Drimer Berg
Kasper Drimer Berg
BTBirgitte Grønkær Toft
Birgitte Grønkær Toft
Martin Andreas RøderMartin Andreas Røder
Martin Andreas Røder
KBKlaus Brasso
Klaus Brasso
BVBEN Vainer
BEN Vainer
PIPeter Iversen
Peter Iversen

18 December 2023 in EJNMMI Research
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Journal Article
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PIPeter Iversen
Peter Iversen
SKStine Kramer
Stine Kramer
AEAndreas Ebbehoj
Andreas Ebbehoj
ESEsben Søndergaard
Esben Søndergaard
KSKirstine Stochholm
Kirstine Stochholm
KHKarin Hjorthaug
Karin Hjorthaug
Background: Both [18F]FDOPA (FDOPA) and [68Ga]DOTATOC PET/CT (DOTATOC) are widely used for detection of pheochromocytomas/paraganglioma (PPGL). However, direct comparisons of the performance of the two tracers are only available in small series. We conducted a retrospective comparative analysis of FDOPA and DOTATOC to assess their sensitivity and accuracy in detecting PPGL when administered based on suspicion of PPGL. We consecutively included patients referred on suspicion of PPGL or PPGL recurrence who were scanned with both FDOPA and DOTATOC. Both scans were reviewed retrospectively by two experienced observers, who were blinded to the final diagnosis. The assessment was made both visually and quantitatively. The final diagnosis was primarily based on pathology. Results: In total, 113 patients were included (97 suspected of primary PPGL and 16 suspected of recurrence). Of the 97 patients, 51 had pheochromocytomas (PCC) (in total 55 lesions) and 6 had paragangliomas (PGL) (in total 7 lesions). FDOPA detected and correctly localized all 55 PCC, while DOTATOC only detected 25 (sensitivity 100% vs. 49%, p < 0.0001; specificity 95% vs. 98%, p = 1.00). The negative predictive value (100% vs. 63%, p < 0.001) and diagnostic accuracy (98% vs. 70%, p < 0.01) were higher for FDOPA compared to DOTATOC. FDOPA identified 6 of 6 patients with hormone producing PGL, of which one was negative on DOTATOC. Diagnostic performances of FDOPA and DOTATOC were similar in the 16 patients with previous PPGL suspected of recurrence. Conclusions: FDOPA is superior to DOTATOC for localization of PCC. In contrast to DOTATOC, FDOPA also identified all PGL but with a limited number of patient cases.

16 August 2021 in Scandinavian Journal of Surgery
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PIPeter Iversen
Peter Iversen
AAAnne K. Arveschoug
Anne K. Arveschoug
LRLars Rejnmark
Lars Rejnmark
LRLars Rolighed
Lars Rolighed
Preoperative localization of pathologic parathyroid glands is essential in the preparation of a parathyroidectomy. We evaluated the use of a C-11 methionine positron emission tomography/computed tomography scan in a 7-year period in selected patients with primary hyperparathyroidism. The indications to perform a C-11 methionine positron emission tomography/computed tomography were either persistent primary hyperparathyroidism after parathyroidectomy or inconclusive preoperative localization on ultrasound and sestaMIBI. A group of 36 patients was referred for a C-11 methionine positron emission tomography/computed tomography. Biochemical data, pathology, and results of sestaMIBI were collected retrospectively. The primary hyperparathyroidism patients were divided into two groups. In group 1 (N = 17), the C-11 methionine positron emission tomography/computed tomography was performed before parathyroidectomy. In group 2 (N = 19), the C-11 methionine positron emission tomography/computed tomography was performed after unsuccessful parathyroidectomy and before a reoperation. Overall, in 30 of the 36 patients (83%), C-11 methionine positron emission tomography/computed tomography identified a true-positive pathologic parathyroid gland confirmed by an experienced pathologist, consistent with a positive predictive value of 91%. In group 1, 94% of the patients (N = 16) had pathologic parathyroid tissue identified by C-11 methionine positron emission tomography/computed tomography. This resulted in a clinical benefit in 13 patients (76%). In group 2, the benefit was slightly lower, as 74% of the patients (N = 14) had a true-positive C-11 methionine positron emission tomography/computed tomography scan resulting in a clinical benefit in nine patients (47%). In two selected groups of patients planned for an initial operation or reoperation of primary hyperparathyroidism and inconclusive conventional imaging, we found C-11 methionine positron emission tomography/computed tomography to give parathyroid surgeons a clinical benefit in the majority of cases, electing the patients for unilateral surgery.