HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sjögreen, K. Articles by Strand, S.-E. Search for Related Content PubMed PubMed Citation Articles by Sjögreen, K. Articles by Strand, S.-E.

An Activity Quantification Method Based on Registration of CT and Whole-Body Scintillation Camera Images, with Application to ¹³¹I

Department of Radiation Physics, Jubileum Institute, University Hospital, Lund University, Lund, Sweden

View larger version (56K): [in a new window]   FIGURE 1. Flow chart of activity quantification method using 3 different image types: anteroposterior WB scans, WB scintillation camera transmission scan, and CT scan. Coordinate system used is shown at bottom. Text in bold denotes images. CA = raw anterior scan; CP = raw posterior scan; PA = primary-count-rate image, anterior; PP = primary-count-rate image, posterior; AMTCT = attenuation map from scintillation camera transmission scan; (x,y,z) = mass density distribution; GM = geometric mean image; AMCT = attenuation map from CT scan; µ/ = mass attenuation coefficient; AM = energy-converted WB attenuation map; actVOI = VOI activity.

View larger version (92K): [in a new window]   FIGURE 2. Simulated images of activity distribution that mimics current patient group. Images were obtained as the geometric mean of anterior and posterior projections. (A) Image representing defined activity distribution, obtained by analytic integration. (B) Monte Carlo simulated image, for the camera system used. (C) Image corrected for scatter and septal penetration. (D) Image corrected for attenuation, scatter, and septal penetration.

View larger version (13K): [in a new window]   FIGURE 3. (A) Radial PRFs used for deconvolution scatter and penetration compensation. PRFs for depths of 20, 15, and 10 cm in water, in order from top to bottom. (B) A deconvolution filter that was applied to clinical image in Figure 6, using PRF for a depth of 10 cm.

View larger version (15K): [in a new window]   FIGURE 4. Calibration of Hounsfield units of CT images to values of mass density. Values were obtained from experimental measurements of set of calibration materials (•), and theoretic values were calculated as sum of linear attenuation coefficient values weighted by spectral distribution of CT scanner (). Dashed line represents bilinear relationship that was fitted to data.

View larger version (32K): [in a new window]   FIGURE 5. Attenuation maps for 1 patient. (A) The image AM, obtained by energy conversion of attenuation map from WB scintillation camera transmission scanning (AMTCT). (B) Attenuation map obtained from CT (AMCT). (C–E) Plots of attenuation map values, as function of horizontal position, at positions indicated by horizontal lines in images. Profiles of AM (solid line) and AMCT (dashed line).

View larger version (122K): [in a new window]   FIGURE 6. Clinical geometric mean image acquired at 24 h after therapeutic injection. (A) Raw data image. (B) Image corrected for attenuation and scatter penetration. (C) Quantification of organ activities using regions defined from CT, applied to activity image, A(x,z). (D) Coronal CT slice, for which marked regions were manually segmented in slices where outer boundaries of organs were best visualized.