Original paper<br>A new two-step accurate CT-MRI fusion technique for post-implant prostate cancer

Hiroaki Kunogi; Hidehiro Hojo; Yoshiaki Wakumoto; Anneyuko I. Saito; Satoshi Ishikura; Yuki Yamashiro; Ryouhei Kuwatsuru; Keisuke Sasai

doi:10.5114/jcb.2015.51290

eISSN: 2081-2841
ISSN: 1689-832X

Journal of Contemporary Brachytherapy

Current Issue Archive Supplements Articles in Press Journal Information Aims and Scope Editorial Office Editorial Board Register as Author Register as Reviewer Instructions for Authors Abstracting and indexing Subscription Advertising Information Links

Editorial System

Submit your Manuscript

2/2015
vol. 7

Send email

Copy url:

abstract:

Original paper
A new two-step accurate CT-MRI fusion technique for post-implant prostate cancer

Hiroaki Kunogi

,

Hidehiro Hojo

,

Yoshiaki Wakumoto

,

Anneyuko I. Saito

,

Satoshi Ishikura

,

Yuki Yamashiro

,

Ryouhei Kuwatsuru

,

Keisuke Sasai

J Contemp Brachytherapy 2015; 7, 2: 117-121

DOI: https://doi.org/10.5114/jcb.2015.51290

Online publish date: 2015/04/30

View full text Get citation

Purpose: To develop an accurate method of fusing computed tomography (CT) with magnetic resonance imaging (MRI) for post-implant dosimetry after prostate seed implant brachytherapy.

Material and methods: Prostate cancer patients were scheduled to undergo CT and MRI after brachytherapy. We obtained the three MRI sequences on fat-suppressed T1-weighted imaging (FST1-WI), T2-weighted imaging (T2-WI), and T2*-weighted imaging (T2*-WI) in each patient. We compared the lengths and widths of 450 seed source images in the 10 study patients on CT, FST1-WI, T2-WI, and T2*-WI. After CT-MRI fusion using source positions by the least-squares method, we decided the center of each seed source and measured the distance of these centers between CT and MRI to estimate the fusion accuracy.

Results: The measured length and width of the seeds were 6.1 ± 0.5 mm (mean ± standard deviation) and 3.2 ± 0.2 mm on CT, 5.9 ± 0.4 mm, and 2.4 ± 0.2 mm on FST1-WI, 5.5 ± 0.5 mm and 1.8 ± 0.2 mm on T2-WI, and 7.8 ± 1.0 mm and 4.1 ± 0.7 mm on T2*-WI, respectively. The measured source location shifts on CT/FST1-WI and CT/T2-WI after image fusion in the 10 study patients were 0.9 ± 0.4 mm and 1.4 ± 0.2 mm, respectively. The shift on CT/FST1-WI was less than on CT/T2-WI (p = 0.005).

Conclusions: For post-implant dosimetry after prostate seed implant brachytherapy, more accurate fusion of CT and T2-WI is achieved if CT and FST1-WI are fused first using the least-squares method and the center position of each source, followed by fusion of the FST1-WI and T2-WI images. This method is more accurate than direct image fusion.

keywords:

Original paperA new two-step accurate CT-MRI fusion technique for post-implant prostate cancer

Hiroaki Kunogi , Hidehiro Hojo , Yoshiaki Wakumoto , Anneyuko I. Saito , Satoshi Ishikura , Yuki Yamashiro , Ryouhei Kuwatsuru , Keisuke Sasai

brachytherapy, fusion, magnetic resonance imaging, post-implant, prostate cance

Original paper
A new two-step accurate CT-MRI fusion technique for post-implant prostate cancer

Hiroaki Kunogi

,

Hidehiro Hojo

,

Yoshiaki Wakumoto

,

Anneyuko I. Saito

,

Satoshi Ishikura

,

Yuki Yamashiro

,

Ryouhei Kuwatsuru

,

Keisuke Sasai