Observer Study of Reconstruction Strategies for Detection of Solitary Pulmonary Nodules Using Hybrid...
Download
1 / 38

Xiaoming Zheng, PhD. 20 October, 2004 - PowerPoint PPT Presentation


  • 79 Views
  • Uploaded on

Observer Study of Reconstruction Strategies for Detection of Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images. Xiaoming Zheng, PhD. 20 October, 2004. Outlines. Lung Cancer and SPECT/PET NeoTect in Lung SPECT Image Reconstructions: RBI vs FBP Hybrid Images: Clinical Reality

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Xiaoming Zheng, PhD. 20 October, 2004' - shadow


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Observer Study of Reconstruction Strategies for Detection of Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

Xiaoming Zheng, PhD.

20 October, 2004


Outlines
Outlines Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • Lung Cancer and SPECT/PET

  • NeoTect in Lung SPECT

  • Image Reconstructions: RBI vs FBP

  • Hybrid Images: Clinical Reality

  • Observer Studies: Human vs Numerical

  • ROC: Receiver Operating Characteristics

  • Results and Conclusions


Leading causes of cancer deaths
Leading Causes of Cancer Deaths Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Nsclc non small cell lung cancer
NSCLC: Non-Small-Cell-Lung-Cancer Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • Surgery is providing the best chance of cure if tumor can be re-sected completely.

  • If cancer has spread to contra-lateral lymph nodes or beyond the chest surgery alone is not useful. Chemotherapy and/or radiotherapy are usually applied. These measures are rarely curative


Spn solitary pulmonary nodule
SPN: Solitary Pulmonary Nodule Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • Approx. 30% of new cases of lung cancer are found as an SPN

  • An SPN is defined as:

    • single pulmonary lesion

    • well defined borders

    • mean diameter not more than 3 cm

  • Found in 1 : 500 chest X-rays


Spect and pet
SPECT and PET Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Neotect spect vs fdg pet
NeoTect/SPECT vs FDG/PET Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Neotect 99m tc depreotide
NeoTect ( Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images99mTc-Depreotide)

  • Binds to Somatostatin receptors, which are over-expressed in lung cancer (NSCLC and SCLC)

  • Has a negative predictive value of up to 98% in combination with CT or chest X-ray for SPN

  • Procedure is non-invasive

  • 99mTc-labelled - readily available

  • Procedure is easy

  • Can be used wherever SPECT is available


Binding region for SSTR* Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

N

H

2

N

H

2

(N-Me)Phe-Tyr

O

D-Trp

O

O

H

N

N

N

O

2

Lys

N

H

T

c

Hcy-Val

O

N

H

S

H

N

2

O

NeoTect

  • - a small synthetic peptide

  • - 10 amino acids, mol. wt. 1358 Da

  • - binding region for the somatostatin receptor

  • - radio-labeled with 99mTc


How neotect works
How NeoTect Works Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • Malignant tumors over-express somatostatin receptors (SSTRs)

  • NeoTect binds to and detects SSTRs

  • Most benign lesions do not over-express SSTRs


Normal Transaxial SPECT Images Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


CT Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

Coronal SPECT

72 yr female smoker, complaining of weight loss; chest x-ray: 2.5 cm LUL lesion; CT: LUL 2.0 cm spiculated mass; Histopathology (CT guided FNA biopsy): poorly-differentiated adenocarcinoma

Transaxial SPECT


Aims of this work
Aims of This Work Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • Use hybrid images of lung tumor imaging agent Tc-99m NeoTect in Localization Receiver Operating Characteristic (LROC) studies to determine reconstruction parameters and whether iterative reconstruction with attenuation, scatter, and distant resolution compensation should replace FBP clinically.


Why hybrid images
Why Hybrid Images Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • The Optimization of reconstruction parameters, and determination of whether iterative reconstruction should replace FBP clinically should be based on tasks which closely approximate the clinical application of the images

  • The use of hybrid images or studies represents a practical alternative to the use of purely clinical acquisitions for observer studies.


How hybrid images were created
How Hybrid Images Were Created Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • Simulated lesions are added to know normal clinical acquisitions

  • Monte Carlo simulation package SIMIND was used to simulate lesions.

  • Nine normal patient’s projection data were used to create 162 tumors randomly distributed within the lung regions.

  • Tumors were 1 cm in diameter which is the smallest tumor could be detected by CT.


Neotect projections from clinical 9 patients
NeoTect Projections Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT ImagesFrom Clinical 9 Patients


Tumor source projections from monte carlo simulation
Tumor Source Projections Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT ImagesFrom Monte Carlo Simulation


Images reconstructions
Images Reconstructions Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • Iterative Reconstruction: Rescaled Block Iterative Algorithm including attenuation, scatter, and distance resolution compensation. Parameters tested: iteration 1,3,5,7,10 and post Gaussian filter FWHM 0,1,2,3,4 pixels

  • Filtered Back-Projection: Parameters tested: Butterworth filter cut-off frequencies: 0.10, 0.15, 0.20, 0.25 and 0.30 pixel-1


Filtered back projection
Filtered Back-Projection Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Butterworth filter and cutoff frequency
Butterworth Filter and Cutoff Frequency Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Fbp reconstructed images
FBP Reconstructed Images Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Iterative reconstruction
Iterative Reconstruction Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Rescaled block iterative reconstruction algorithm
Rescaled Block Iterative Reconstruction Algorithm Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Attenuation compensation
Attenuation Compensation Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Scatter compensation
Scatter Compensation Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Resolution compensation
Resolution Compensation Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Rbi reconstructed images
RBI Reconstructed Images Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Receiver operating characteristics
Receiver Operating Characteristics Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Images for observers
Images for Observers Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Numerical observers
Numerical Observers Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Types of channels
Types of Channels Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Human Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

Observer

Interface

RBI


Human Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

Observer

Interface

FBP


Numerical observer results rbi
Numerical Observer Results: RBI Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Numerical observer results fbp
Numerical Observer Results: FBP Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Human observer results
Human Observer Results Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images


Conclusions
Conclusions Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • Iterative RBI-EM including all corrections performs better than that of FBP.

  • The best performance reconstruction strategy is RBI-EM with 5 iteration and 1 pixel FWHM in Gaussian post-filtering.

  • Numerical observer with and without mean background subtraction set the upper and lower bounds achievable by human observer.


Acknowlegements
Acknowlegements Solitary Pulmonary Nodules Using Hybrid NeoTect SPECT Images

  • This work was supported by a Charles Sturt University Special Study grant and a NIH research grant.

  • The co-authors of this work are Prof Mike King, Dr Howard Gifford and Dr Hennie Pretorius at the University of Massachusetts Medical School.


ad