Calcifications Are Potential Surrogates for Prostate Localization in Image-Guided Radiotherapy

Zeng, Guanggen; McGowan, Tom; Larsen, Tessa; Bruce, Lisa; Moran, Natasha Kouvaleski Saviano; Tsao, Jonathan; MacPherson, M

doi:10.1016/j.ijrobp.2008.07.021

Cited by 30 publications

(30 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is larger than the fraction of one-third previously reported for intraprostatic calcifications > 2 mm in diameter. 36 To reduce the number of false-positive GFM candidates, the existence of a signal void in the first echo of the MEGRE images, originating from the GFM candidate, was required (discrimination step 5). This was analogous to prioritizing objects with the largest magnetic susceptibility, i.e., the GFM.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Registration free automatic identification of gold fiducial markers in MRI target delineation images for prostate radiotherapy

et al. 2017

View full text Add to dashboard Cite

Purpose: The superior soft tissue contrast of magnetic resonance imaging (MRI) compared to computed tomography (CT) has urged the integration of MRI and elimination of CT in radiotherapy treatment (RT) for prostate. An intraprostatic gold fiducial marker (GFM) appears hyperintense on CT. On T2-weighted (T2w) MRI target delineation images, the GFM appear as a small signal void similar to calcifications and post biopsy fibrosis. It can therefore be difficult to identify the markers without CT. Detectability of GFMs can be improved using additional MR images, which are manually registered to target delineation images. This task requires manual labor, and is associated with interoperator differences and image registration errors. The aim of this work was to develop and evaluate an automatic method for identification of GFMs directly in the target delineation images without the need for image registration. Methods: T2w images, intended for target delineation, and multiecho gradient echo (MEGRE) images intended for GFM identification, were acquired for prostate cancer patients. Signal voids in the target delineation images were identified as GFM candidates. The GFM appeared as round, symmetric, signal void with increasing area for increasing echo time in the MEGRE images. These image features were exploited for automatic identification of GFMs in a MATLAB model using a patient training dataset (n = 20). The model was validated on an independent patient dataset (n = 40). The distances between the identified GFM in the target delineation images and the GFM in CT images were measured. A human observatory study was conducted to validate the use of MEGRE images. Results: The sensitivity, specificity, and accuracy of the automatic method and the observatory study was 84%, 74%, 81% and 98%, 94%, 97%, respectively. The mean absolute difference in the GFM distances for the automatic method and observatory study was 1.28 AE 1.25 mm and 1.14 AE 1.06 mm, respectively. Conclusions: Multiecho gradient echo images were shown to be a feasible and reliable way to perform GFM identification. For clinical practice, visual inspection of the results from the automatic method is needed at the current stage.

show abstract

Section: Discussionmentioning

confidence: 99%

“…36 The calcifications may have a similar signal behavior as GFMs in T2w sequences, i.e., a signal void. 25,37,38 The same signal behavior may also be found from vessels in the prostate or post biopsy fibrosis and hemorrhages.…”

Section: Introductionmentioning

confidence: 99%

Registration free automatic identification of gold fiducial markers in MRI target delineation images for prostate radiotherapy

et al. 2017

View full text Add to dashboard Cite

show abstract

“…73 It has been reported that up to 35% of patients undergoing prostate radiotherapy have calcifications visible on CBCT. 74 PCs may be detected coincidentally from histological or radiological findings, and patients are often asymptomatic. The significance of PCs is not well understood, but there is some evidence to suggest an association of PCs and prostatic inflammation, lower urinary tract symptoms and PCa.…”

Section: Prostate Calcifications As Fiducial Markersmentioning

confidence: 99%

“…Zeng et al 74 investigated the stability of PCs with a view to using them as a surrogate for prostate position during IGRT and found that they were stable. A subsequent study recommended the use of central intraprostatic PCs for IGRT.…”

Section: Prostate Calcifications As Fiducial Markersmentioning

confidence: 99%

Fiducial marker guided prostate radiotherapy: a review

O’Neill¹,

Jain²,

Hounsell³

et al. 2016

The British Journal of Radiology

View full text Add to dashboard Cite

Image-guided radiotherapy (IGRT) is an essential tool in the accurate delivery of modern radiotherapy techniques. Prostate radiotherapy positioned using skin marks or bony anatomy may be adequate for delivering a relatively homogeneous whole-pelvic radiotherapy dose, but these surrogates are not reliable when using reduced margins, dose escalation or hypofractionated stereotactic radiotherapy. Fiducial markers (FMs) for prostate IGRT have been in use since the 1990s. They require surgical implantation and provide a surrogate for the position of the prostate gland. A variety of FMs are available and they can be used in a number of ways. This review aimed to establish the evidence for using prostate FMs in terms of feasibility, implantation procedures, types of FMs used, FM migration, imaging modalities used and the clinical impact of FMs. A search strategy was defined and a literature search was carried out in Medline. Inclusion and exclusion criteria were applied, which resulted in 50 articles being included in this review. The evidence demonstrates that FMs provide a more accurate surrogate for the position of the prostate than either external skin marks or bony anatomy. A combination of FM alignment and soft-tissue analysis is currently the most effective and widely available approach to ensuring accuracy in prostate IGRT. FM implantation is safe and well tolerated. FM migration is possible but minimal. Standardization of all techniques and procedures in relation to the use of prostate FMs is required. Finally, a clinical trial investigating a non-surgical alternative to prostate FMs is introduced.

show abstract

“…This is why fused multimodality data sets are frequently used for contouring. Several imaging methods can be used in combination with CT for better localization and definition of the prostate: the most common are cone-beam computed tomography (Oldham et al 2005;Zeng et al 2008), magnetic resonance imaging (MRI) (Raaymakers et al 2009) and ultrasound (US) imaging (Fraser et al 2010;Fung et al 2006;Lattanzi et al1999;Mayyas et al 2013;Morr et al 2002;Robinson et al 2012;Wein et al 2007). US is currently mostly used for segmentation and IGRT (Molloy et al 2004;Smith et al 2007) because it provides a quantitative and cost-effective imaging technique that avoids unwanted radiation dose to the patient.…”

Section: Introductionmentioning

confidence: 99%

Automated Computed Tomography–Ultrasound Cross-Modality 3-D Contouring Algorithm for Prostate

Ermacora¹,

Pesente

Pascoli

et al. 2015

Ultrasound in Medicine & Biology

View full text Add to dashboard Cite

Calcifications Are Potential Surrogates for Prostate Localization in Image-Guided Radiotherapy

Cited by 30 publications

References 10 publications

Registration free automatic identification of gold fiducial markers in MRI target delineation images for prostate radiotherapy

Registration free automatic identification of gold fiducial markers in MRI target delineation images for prostate radiotherapy

Fiducial marker guided prostate radiotherapy: a review

Automated Computed Tomography–Ultrasound Cross-Modality 3-D Contouring Algorithm for Prostate

Contact Info

Product

Resources

About