Interactive, multi-modality image registrations for combined MRI/MRSI-planned HDR prostate brachytherapy

Department of Radiology and Biomedical Imaging, University of California, San Francisco, USA.
Journal of Contemporary Brachytherapy (Impact Factor: 1.28). 03/2011; 3(1):26-31. DOI: 10.5114/jcb.2011.21040
Source: PubMed


This study presents the steps and criteria involved in the series of image registrations used clinically during the planning and dose delivery of focal high dose-rate (HDR) brachytherapy of the prostate.
Three imaging modalities - Magnetic Resonance Imaging (MRI), Magnetic Resonance Spectroscopic Imaging (MRSI), and Computed Tomography (CT) - were used at different steps during the process. MRSI is used for identification of dominant intraprosatic lesions (DIL). A series of rigid and nonrigid transformations were applied to the data to correct for endorectal-coil-induced deformations and for alignment with the planning CT. Mutual information was calculated as a morphing metric. An inverse planning optimization algorithm was applied to boost dose to the DIL while providing protection to the urethra, penile bulb, rectum, and bladder. Six prostate cancer patients were treated using this protocol.
The morphing algorithm successfully modeled the probe-induced prostatic distortion. Mutual information calculated between the morphed images and images acquired without the endorectal probe showed a significant (p = 0.0071) increase to that calculated between the unmorphed images and images acquired without the endorectal probe. Both mutual information and visual inspection serve as effective diagnostics of image morphing. The entire procedure adds less than thirty minutes to the treatment planning.
This work demonstrates the utility of image transformations and registrations to HDR brachytherapy of prostate cancer.

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Available from: J Adam M Cunha, Jan 10, 2014
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    • "The choice of the treatment modality of prostate cancer patients depends mainly on the stage of the disease and the prognostic factors [4]. A highly precise diagnosis of the progression of the disease is possible by means of imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), and transrectal ultrasonography (TRUS), in parallel with clinical assessment (digital rectal examination – DRE) and PSA test results [5–8]. Knowledge of the TNM classification and results of pathology grading of the cancer makes it possible to select the appropriate treatment option. "
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    ABSTRACT: Brachytherapy is a curative alternative to radical prostatectomy or external beam radiation [i.e. 3D conformal external beam radiation therapy (CRT), intensity-modulated radiation therapy (IMRT)] with comparable long-term survival and biochemical control and the most favorable toxicity. HDR brachytherapy (HDR-BT) in treatment of prostate cancer is most frequently used together with external beam radiation therapy (EBRT) as a boost (increasing the treatment dose precisely to the tumor). In the early stages of the disease (low, sometimes intermediate risk group), HDR-BT is more often used as monotherapy. There are no significant differences in treatment results (overall survival rate - OS, local recurrence rate - LC) between radical prostatectomy, EBRT and HDR-BT. Low-dose-rate brachytherapy (LDR-BT) is a radiation method that has been known for several years in treatment of localized prostate cancer. The LDR-BT is applied as a monotherapy and also used along with EBRT as a boost. It is used as a sole radical treatment modality, but not as a palliative treatment. The use of brachytherapy as monotherapy in treatment of prostate cancer enables many patients to keep their sexual functions in order and causes a lower rate of urinary incontinence. Due to progress in medical and technical knowledge in brachytherapy ("real-time" computer planning systems, new radioisotopes and remote afterloading systems), it has been possible to make treatment time significantly shorter in comparison with other methods. This also enables better protection of healthy organs in the pelvis. The aim of this publication is to describe both brachytherapy methods.
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    No preview · Article · Jan 2016 · Cancer/Radiothérapie