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Image Processing for Quantitative Scintillation-Camera Imaging. Application to Radionuclide Therapy.

Sjögreen Gleisner, Katarina LU (2001)
Abstract (Swedish)
Popular Abstract in Swedish

Behandling med radionuklidterapi baseras på radioaktiva läkemedel, d.v.s. läkemedel som i sig består av ett radioaktivt ämne, eller som kopplats till en radionuklid. Den strålningsenergi som avges vid de radioaktiva sönderfallen absorberas i vävnad och ger en lokalt absorberad stråldos där läkemedlet tas upp. Viktigt är härvid att upptaget är högre i patologisk vävnad än i normal, så att stråldosen till strålningskänslig normal vävnad, t.ex. benmärg, kan hållas under toxicitetsnivån, medan tumören får en tillräckligt hög stråldos. För att verifiera upptagsmönstret av läkemedlet och för att optimera läkemedels-doseringen, bör den absorberade stråldosen till viktiga vävnader och organ mätas för... (More)
Popular Abstract in Swedish

Behandling med radionuklidterapi baseras på radioaktiva läkemedel, d.v.s. läkemedel som i sig består av ett radioaktivt ämne, eller som kopplats till en radionuklid. Den strålningsenergi som avges vid de radioaktiva sönderfallen absorberas i vävnad och ger en lokalt absorberad stråldos där läkemedlet tas upp. Viktigt är härvid att upptaget är högre i patologisk vävnad än i normal, så att stråldosen till strålningskänslig normal vävnad, t.ex. benmärg, kan hållas under toxicitetsnivån, medan tumören får en tillräckligt hög stråldos. För att verifiera upptagsmönstret av läkemedlet och för att optimera läkemedels-doseringen, bör den absorberade stråldosen till viktiga vävnader och organ mätas för varje patient som genomgår behandling.



Den absorberade stråldosen vid radionuklidterapi är fundamentalt beroende av fördelningen av det radioaktiva ämnet i kroppen, och hur det omfördelas över tiden. För att följa ämnets fördelning och passage genom kroppen görs mätningar med en s.k. gammakamera, vid ett antal tillfällen efter injektion, antingen som still-bilder, helkroppsscanning, eller som tomografi för att ge tre-dimensionella bilder. Ibland kombineras dessa med mätningar med röntgen-tomografi (CT), vilka kan användas för att korrigera för tekniska och fysikaliska begränsningar i gammakamerabilderna, samt ge anatomiska bilder som komplement till de funktionella bilder som resulterar från gammakamera-undersökning.



Syftet med arbetet som rapporteras i denna avhandling har varit att studera och utveckla metoder för behandling och analys av gammakamerabilder, med syftet att kompensera för fysikaliska och tekniska begränsningar i bildtagningsprocessen. Speciellt har metoder för samregistrering*, segmentering** och aktivitetskvantifiering*** utvecklats. Den huvudsakliga applikationen har varit bilder tagna i samband med radionuklidterapi för B-cells-lymfom med 131-I-märkta monoklonala antikroppar, där kvantitativa bilder behövs som bas för en bestämning av fördelningen av absorberad dos.



*Samregistrering: geometrisk matchning av två bilder så att de stämmer överens anatomiskt, d.v.s. motsvarande pixlar i de två bilderna innehåller information som representerar exakt samma position i patienten. **Segmentering: utlinjering/inringning av intressanta områden i bilderna. ***Aktivitetskvantifiering: Absolutmätning av koncentrationen av radioaktivt läkemedel. (Less)
Abstract
Individual-based determinations of the absorbed dose in radionuclide therapy largely rely on absolute measurement of the activity distribution and its redistribution over time. Scintillation-camera imaging is the most commonly employed measuring technique, applied in planar or SPECT mode, sometimes in combination with structural images from CT. In this thesis, methods for processing and analysis of scintillation-camera images have been studied, with the intent to compensate for the physical limitations involved in the imaging process and thereby improve the quantification accuracy. In particular, methods for image registration and segmentation have been developed.



Evaluation of the earlier SPECT based quantification... (More)
Individual-based determinations of the absorbed dose in radionuclide therapy largely rely on absolute measurement of the activity distribution and its redistribution over time. Scintillation-camera imaging is the most commonly employed measuring technique, applied in planar or SPECT mode, sometimes in combination with structural images from CT. In this thesis, methods for processing and analysis of scintillation-camera images have been studied, with the intent to compensate for the physical limitations involved in the imaging process and thereby improve the quantification accuracy. In particular, methods for image registration and segmentation have been developed.



Evaluation of the earlier SPECT based quantification program revealed limitations for the measurement of small volumes, their activity and contrast, in situations where the object contrast deviated from 100%. A 3D deformable segmentation method was developed and applied for SPECT images. In preliminary evaluations, this method gave an adequate boundary, also in situations with low contrast and high levels of noise. For registration of SPECT and CT images, a method was developed where the possibility to use images acquired in the Compton scatter region was explored. The registration accuracy was obtained to about 10 mm, where the largest deviations occurred for slices with heterogeneous activity distributions. To achieve automation, this method was further developed by applying mutual information as similarity measure and spatial transformations in 3D. This registration method was applied for activity quantification and absorbed dose calculations in 3D, using the combined information from CT and SPECT.



For planar image activity quantification, a 2D method for registration of whole-body emission and transmission images was developed, including a tailored spatial transformation. The accuracy was obtained to below pixel level (< 3.6 mm) for simulated images, to 9 mm in comparison to point markers for patients. A quantification method based on conjugate scintillation-camera images was also developed, in which a registered CT image was used for attenuation correction, background compensation and segmentation of organs. Evaluation using Monte Carlo simulated images showed an accuracy of within 10% for organ activity quantification.



Throughout this thesis, the major application has been images acquired in association with radionuclide therapy using an 131I labeled monoclonal antibody. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Dr Flux, Glenn, Royal Marsden NHS Trust & Institute of Cancer Research, London, UK.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
tomografi, radiologi, Klinisk fysiologi, medical instrumentation, tomography, radiology, 131-I, Clinical physics, SPECT, conjugate-view, volume quantification, activity quantification, image registration, image segmentation, medicinsk instrumentering, Nuclear medicine, radiobiology, Nukleärmedicin, radiobiologi, Radiopharmaceutical technology, Radiofarmaceutisk teknik
pages
134 pages
publisher
Department of Radiation Physics, Lund university
defense location
N/A
defense date
2001-09-28 10:15
ISBN
91-628-4903-4
language
English
LU publication?
yes
id
80794849-16ac-459c-a6a4-558ac55db928 (old id 41874)
date added to LUP
2007-07-31 10:55:33
date last changed
2016-09-19 08:45:02
@misc{80794849-16ac-459c-a6a4-558ac55db928,
  abstract     = {Individual-based determinations of the absorbed dose in radionuclide therapy largely rely on absolute measurement of the activity distribution and its redistribution over time. Scintillation-camera imaging is the most commonly employed measuring technique, applied in planar or SPECT mode, sometimes in combination with structural images from CT. In this thesis, methods for processing and analysis of scintillation-camera images have been studied, with the intent to compensate for the physical limitations involved in the imaging process and thereby improve the quantification accuracy. In particular, methods for image registration and segmentation have been developed.<br/><br>
<br/><br>
Evaluation of the earlier SPECT based quantification program revealed limitations for the measurement of small volumes, their activity and contrast, in situations where the object contrast deviated from 100%. A 3D deformable segmentation method was developed and applied for SPECT images. In preliminary evaluations, this method gave an adequate boundary, also in situations with low contrast and high levels of noise. For registration of SPECT and CT images, a method was developed where the possibility to use images acquired in the Compton scatter region was explored. The registration accuracy was obtained to about 10 mm, where the largest deviations occurred for slices with heterogeneous activity distributions. To achieve automation, this method was further developed by applying mutual information as similarity measure and spatial transformations in 3D. This registration method was applied for activity quantification and absorbed dose calculations in 3D, using the combined information from CT and SPECT.<br/><br>
<br/><br>
For planar image activity quantification, a 2D method for registration of whole-body emission and transmission images was developed, including a tailored spatial transformation. The accuracy was obtained to below pixel level (&lt; 3.6 mm) for simulated images, to 9 mm in comparison to point markers for patients. A quantification method based on conjugate scintillation-camera images was also developed, in which a registered CT image was used for attenuation correction, background compensation and segmentation of organs. Evaluation using Monte Carlo simulated images showed an accuracy of within 10% for organ activity quantification.<br/><br>
<br/><br>
Throughout this thesis, the major application has been images acquired in association with radionuclide therapy using an 131I labeled monoclonal antibody.},
  author       = {Sjögreen Gleisner, Katarina},
  isbn         = {91-628-4903-4},
  keyword      = {tomografi,radiologi,Klinisk fysiologi,medical instrumentation,tomography,radiology,131-I,Clinical physics,SPECT,conjugate-view,volume quantification,activity quantification,image registration,image segmentation,medicinsk instrumentering,Nuclear medicine,radiobiology,Nukleärmedicin,radiobiologi,Radiopharmaceutical technology,Radiofarmaceutisk teknik},
  language     = {eng},
  pages        = {134},
  publisher    = {ARRAY(0x8c46bb8)},
  title        = {Image Processing for Quantitative Scintillation-Camera Imaging. Application to Radionuclide Therapy.},
  year         = {2001},
}