Share Email Print
cover

Proceedings Paper

Dynamic dosimetry and edema detection in prostate brachytherapy: a complete system
Author(s): A. Jain; A. Deguet; I. Iordachita; G. Chintalapani; J. Blevins; Y. Le; E. Armour; C. Burdette; D. Song; G. Fichtinger
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Purpose: Brachytherapy (radioactive seed insertion) has emerged as one of the most effective treatment options for patients with prostate cancer, with the added benefit of a convenient outpatient procedure. The main limitation in contemporary brachytherapy is faulty seed placement, predominantly due to the presence of intra-operative edema (tissue expansion). Though currently not available, the capability to intra-operatively monitor the seed distribution, can make a significant improvement in cancer control. We present such a system here. Methods: Intra-operative measurement of edema in prostate brachytherapy requires localization of inserted radioactive seeds relative to the prostate. Seeds were reconstructed using a typical non-isocentric C-arm, and exported to a commercial brachytherapy delivery system. Technical obstacles for 3D reconstruction on a non-isocentric C-arm include pose-dependent C-arm calibration; distortion correction; pose estimation of C-arm images; seed reconstruction; and C-arm to TRUS registration. Results: In precision-machined hard phantoms with 40-100 seeds and soft tissue phantoms with 45-87 seeds, we correctly reconstructed the seed implant shape with an average 3D precision of 0.35 mm and 0.24 mm, respectively. In a DoD Phase-1 clinical trial on 6 patients with 48-82 planned seeds, we achieved intra-operative monitoring of seed distribution and dosimetry, correcting for dose inhomogeneities by inserting an average of 4.17 (1-9) additional seeds. Additionally, in each patient, the system automatically detected intra-operative seed migration induced due to edema (mean 3.84 mm, STD 2.13 mm, Max 16.19 mm). Conclusions: The proposed system is the first of a kind that makes intra-operative detection of edema (and subsequent re-optimization) possible on any typical non-isocentric C-arm, at negligible additional cost to the existing clinical installation. It achieves a significantly more homogeneous seed distribution, and has the potential to affect a paradigm shift in clinical practice. Large scale studies and commercialization are currently underway.

Paper Details

Date Published: 31 March 2008
PDF: 14 pages
Proc. SPIE 6918, Medical Imaging 2008: Visualization, Image-Guided Procedures, and Modeling, 69181Y (31 March 2008); doi: 10.1117/12.772352
Show Author Affiliations
A. Jain, Johns Hopkins Univ. (United States)
A. Deguet, Johns Hopkins Univ. (United States)
I. Iordachita, Johns Hopkins Univ. (United States)
G. Chintalapani, Johns Hopkins Univ. (United States)
J. Blevins, Acoustic MedSystems, Inc. (United States)
Y. Le, Johns Hopkins Univ. School of Medicine (United States)
E. Armour, Johns Hopkins Univ. School of Medicine (United States)
C. Burdette, Acoustic MedSystems, Inc. (United States)
D. Song, Johns Hopkins Univ. School of Medicine (United States)
G. Fichtinger, Queen's Univ. (Canada)


Published in SPIE Proceedings Vol. 6918:
Medical Imaging 2008: Visualization, Image-Guided Procedures, and Modeling
Michael I. Miga; Kevin Robert Cleary, Editor(s)

© SPIE. Terms of Use
Back to Top