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Aspects of PET-CT in prostate cancer. Protocol optimization, diagnostic accuracy, and dosimetry.

Bjöersdorff, Mimmi LU orcid (2022) In Lund University, Faculty of Medicine Doctoral Dissertation Series
Abstract
The PET-CT imaging modality is based on positron emission tomography combined with computed tomography. Before a PET-CT examination, a radioactive tracer (also called a radiopharmaceutical) is intravenously injected into the patient. PET technology images the distribution of this tracer element by detecting the decay. In recent years, PET technology has been developed and improved in hardware and software. In addition, new radioactive tracers have been introduced.
Prostate cancer is one of the most common cancers affecting men. PET-CT is used to evaluate the suspected primary tumour, for staging, to evaluate the treatment, and to diagnose suspected recurrences. In 2017, the PET-CT machine park at Skåne University Hospital was upgraded... (More)
The PET-CT imaging modality is based on positron emission tomography combined with computed tomography. Before a PET-CT examination, a radioactive tracer (also called a radiopharmaceutical) is intravenously injected into the patient. PET technology images the distribution of this tracer element by detecting the decay. In recent years, PET technology has been developed and improved in hardware and software. In addition, new radioactive tracers have been introduced.
Prostate cancer is one of the most common cancers affecting men. PET-CT is used to evaluate the suspected primary tumour, for staging, to evaluate the treatment, and to diagnose suspected recurrences. In 2017, the PET-CT machine park at Skåne University Hospital was upgraded from conventional PET-CT systems to newly developed and improved PET-CT systems.
Previously, the radioactive tracer [18F]fluorocholine ([18F]FCH) was used in PETCT examinations of prostate cancer at Skåne University Hospital. However, [18F]FCH is not specific or sensitive enough to examine prostate cancer, and therefore, in 2019, it was replaced by [18F]prostate-specific membrane antigen-1007 ([18F]PSMA-1007).
In a optimization study, the protocol for the [18F]FCH examination method was optimized for the new PET-CT system in terms of frame duration time and value of the noise reduction factor, β. For injection of 4 MBq/kg [18F]FCH, a frame duration of 1.5 min/bed position with a β-value of 400–550 was required to obtain good image quality.
The accuracy of [18F]FCH PET-CT for staging primary lymph node metastases has been validated, with low sensitivity (43%) and moderate specificity (70%) reported. To examine these results more in-depth, a second study was conducted. In this study,
the conventional and novel PET-CT systems were validated based on their ability to accurately detect regional lymph node metastases. This study found large differences in sensitivity and specificity between the PET-CT systems but with almost similar total diagnostic ability. Both studies used histopathology from extended pelvic lymph node dissection as a reference method.
Through a biokinetic and dosimetric study of [18F]PSMA-1007 in patients with prostate cancer, the last study aimed to calculate the absorbed doses and effective dose. The effective dose was calculated to 25 µSv/MBq, corresponding to approximately 8 mSv for a ”standard patient”.
In conclusion, this thesis shows that the reconstruction algorithm BSREM is advantageous over OSEM using [18F]FCH PET-CT, but that the diagnostic accuracy of [18F]FCH PET-CT in detecting pelvic lymph node metastases is not good enough. Furthermore, the thesis shows that the effective dose generated by [18F]PSMA-1007 supporting continued use with the radiopharmaceutical in diagnostic imaging. (Less)
Abstract (Swedish)
PET-CT är baserad på positronemissionstomografi kombinerat med datortomografi. Före en PET-CT-undersökning injiceras ett radioaktivt spårämne (även kallat radiofarmaka) intravenöst i patienten. PET avbildar fördelningen av detta spårämne genom att detektera dess sönderfall. Under de senaste åren har PET-tekniken utvecklats och förbättrats inom hårdvara och mjukvara. Dessutom har nya radioaktiva spårämnen introducerats.
Prostatacancer är en av de vanligaste cancerformerna som drabbar män. PET-CT används för att utvärdera den misstänkta primärtumören, för stadieindelning, för att utvärdera behandlingen samt för att diagnostisera misstänkta återfall. Under 2017 uppgraderades Skånes universitetssjukhus PET-CT-maskinpark från... (More)
PET-CT är baserad på positronemissionstomografi kombinerat med datortomografi. Före en PET-CT-undersökning injiceras ett radioaktivt spårämne (även kallat radiofarmaka) intravenöst i patienten. PET avbildar fördelningen av detta spårämne genom att detektera dess sönderfall. Under de senaste åren har PET-tekniken utvecklats och förbättrats inom hårdvara och mjukvara. Dessutom har nya radioaktiva spårämnen introducerats.
Prostatacancer är en av de vanligaste cancerformerna som drabbar män. PET-CT används för att utvärdera den misstänkta primärtumören, för stadieindelning, för att utvärdera behandlingen samt för att diagnostisera misstänkta återfall. Under 2017 uppgraderades Skånes universitetssjukhus PET-CT-maskinpark från konventionella PET-CT-system till nyutvecklade och förbättrade PET-CT-system.
Tidigare har det radioaktiva spårämnet [18F]fluorokolin ([18F]FCH) använts vid PET-CT-undersökningar av prostatacancer vid Skånes universitetssjukhus. [18F]FCH är dock inte tillräckligt specifik eller känslig för att undersöka prostatacancer, och ersattes därför 2019 av [18F]prostataspecifik membranantigen-1007 ([18F]PSMA-1007).
I en första studie optimerades protokollet för undersökningsmetoden [18F]FCH för det nya PET-CT-systemet när det gäller insamlingstid och värde på brusreduceringsfaktorn, β. Vid injektion av 4 MBq/kg [18F]FCH krävdes en insamlingstid på 1,5 min/bäddposition med ett β-värde på 400–550 för att få bra bildkvalitet.
Noggrannheten för [18F]FCH PET-CT för att detektera primära lymfkörtelmetastaser har validerats, där låg sensitivitet (43 %) och måttlig specificitet (70 %) rapporterades. För att undersöka dessa resultat mer djupgående genomfördes en andra studie. I denna studie validerades de konventionella och nya PET-CT-systemen baserat på deras förmåga att noggrant detektera regionala lymfkörtelmetastaser. Denna studie fann stora skillnader i sensitivitet och specificitet mellan PET-CT-systemen men med nästan liknande total diagnostisk förmåga. Båda studierna använde histopatologi från utökad bäckenlymfkörtelutrymning som referensmetod.
Genom en biokinetik och dosimetri studie av [18F]PSMA-1007 hos patienter med prostatacancer syftade den sista studien till att beräkna de absorberade doserna och den effektiva dosen. Den effektiva dosen beräknades till 25 µSv/MBq, motsvarande cirka 8 mSv för en ”standardpatient”.
Sammanfattningsvis visar denna avhandling att rekonstruktionsalgoritmen BSREM är fördelaktig framför OSEM vid användning av [18F]FCH PET-CT, men att den diagnostiska noggrannheten för [18F]FCH PET-CT för att detektera bäckenlymfkörtelmetastaser inte är tillräckligt bra.
Dessutom visar avhandlingen att den effektiva dosen som genereras av [18F]PSMA-1007 stödjer fortsatt användning med radiofarmakan vid diagnostisk bildbehandling. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • forskare Holstensson, Maria, Department of Clinical Science, Intervention and Technology, Karolinska Institutet
organization
alternative title
Aspekter av PET-CT vid prostatacancer : Protokolloptimering, diagnostisk noggrannhet och dosimetri
publishing date
type
Thesis
publication status
published
subject
keywords
PET-CT, Prostatacancer, [18F]FCH, [18F]PSMA-1007, optimering, diagnostisk noggrannhet, dosimetri, PET-CT, Prostate Cancer, [18F]FCH, [18F]PSMA-1007, Optimization, Diagnostic accuracy, Dosimetric
in
Lund University, Faculty of Medicine Doctoral Dissertation Series
issue
2022:19
pages
74 pages
publisher
Lund University, Faculty of Medicine
defense location
Rum 2005/2007, Carl Bertil Laurells gata 9, Skånes Universitetssjukhus i Malmö. Join by Zoom https://lu-se.zoom.us/j/69719164041
defense date
2022-02-11 09:00:00
ISSN
1652-8220
ISBN
978-91-8021-180-2
language
English
LU publication?
yes
id
cca91135-f6d3-4d9c-8f45-1c90bf945d16
date added to LUP
2022-01-12 14:24:37
date last changed
2022-01-20 08:29:48
@phdthesis{cca91135-f6d3-4d9c-8f45-1c90bf945d16,
  abstract     = {{The PET-CT imaging modality is based on positron emission tomography combined with computed tomography. Before a PET-CT examination, a radioactive tracer (also called a radiopharmaceutical) is intravenously injected into the patient. PET technology images the distribution of this tracer element by detecting the decay. In recent years, PET technology has been developed and improved in hardware and software. In addition, new radioactive tracers have been introduced.<br/>Prostate cancer is one of the most common cancers affecting men. PET-CT is used to evaluate the suspected primary tumour, for staging, to evaluate the treatment, and to diagnose suspected recurrences. In 2017, the PET-CT machine park at Skåne University Hospital was upgraded from conventional PET-CT systems to newly developed and improved PET-CT systems.<br/>Previously, the radioactive tracer [18F]fluorocholine ([18F]FCH) was used in PETCT examinations of prostate cancer at Skåne University Hospital. However, [18F]FCH is not specific or sensitive enough to examine prostate cancer, and therefore, in 2019, it was replaced by [18F]prostate-specific membrane antigen-1007 ([18F]PSMA-1007).<br/>In a optimization study, the protocol for the [18F]FCH examination method was optimized for the new PET-CT system in terms of frame duration time and value of the noise reduction factor, β. For injection of 4 MBq/kg [18F]FCH, a frame duration of 1.5 min/bed position with a β-value of 400–550 was required to obtain good image quality.<br/>The accuracy of [18F]FCH PET-CT for staging primary lymph node metastases has been validated, with low sensitivity (43%) and moderate specificity (70%) reported. To examine these results more in-depth, a second study was conducted. In this study,<br/>the conventional and novel PET-CT systems were validated based on their ability to accurately detect regional lymph node metastases. This study found large differences in sensitivity and specificity between the PET-CT systems but with almost similar total diagnostic ability. Both studies used histopathology from extended pelvic lymph node dissection as a reference method.<br/>Through a biokinetic and dosimetric study of [18F]PSMA-1007 in patients with prostate cancer, the last study aimed to calculate the absorbed doses and effective dose. The effective dose was calculated to 25 µSv/MBq, corresponding to approximately 8 mSv for a ”standard patient”.<br/>In conclusion, this thesis shows that the reconstruction algorithm BSREM is advantageous over OSEM using [18F]FCH PET-CT, but that the diagnostic accuracy of [18F]FCH PET-CT in detecting pelvic lymph node metastases is not good enough. Furthermore, the thesis shows that the effective dose generated by [18F]PSMA-1007 supporting continued use with the radiopharmaceutical in diagnostic imaging.}},
  author       = {{Bjöersdorff, Mimmi}},
  isbn         = {{978-91-8021-180-2}},
  issn         = {{1652-8220}},
  keywords     = {{PET-CT; Prostatacancer; [18F]FCH; [18F]PSMA-1007; optimering; diagnostisk noggrannhet; dosimetri; PET-CT; Prostate Cancer; [18F]FCH; [18F]PSMA-1007; Optimization; Diagnostic accuracy; Dosimetric}},
  language     = {{eng}},
  number       = {{2022:19}},
  publisher    = {{Lund University, Faculty of Medicine}},
  school       = {{Lund University}},
  series       = {{Lund University, Faculty of Medicine Doctoral Dissertation Series}},
  title        = {{Aspects of PET-CT in prostate cancer. Protocol optimization, diagnostic accuracy, and dosimetry.}},
  url          = {{https://lup.lub.lu.se/search/files/111890934/Mimmi_Bj_ersdorff_Kappa.pdf}},
  year         = {{2022}},
}