3. Selection Requirements for Tissue Substitutes

White, D. R.; Booz, J.; Griffith, R. V.; Spokas, J. J.; Wilson, I. J.

doi:10.1093/jicru/os23.1.14

Cited by 14 publications

(22 citation statements)

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“…These simulations encompassed the broad range of clinically‐relevant breast compressed thicknesses (

{b}_z

), normal tissue uptake concentrations (

{C}_b

), spherical and ellipsoid tumor diameters (

{d}_x

{d}_y

{d}_z

), tumor distances from detectors (

{t}_z

), and tumor concentrations (

{C}_t

) observed in our practice with 99m Tc‐sestamibi imaging, as well as some extreme conditions for theoretical modeling. Compressed breasts were simulated by rectangular 15 by 15 by

{b}_z

cm ICRU‐44 soft tissue block, ranging in thickness between 4 and 12 cm in 2 cm intervals 7 . In all acquisitions, the detector heads were placed along the z‐dimension immediately adjacent to the simulated breast (Figure 2).…”

Section: Methodsmentioning

confidence: 99%

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Monte Carlo‐derived ^99mTc uptake quantification with commercial planar MBI: Absolute tumor activity

López

Kappadath

2023

Medical Physics

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Background: Molecular breast imaging (MBI) of 99m Tc-sestamibi is an emerging adjunct qualitative tool in the detection and diagnosis of breast cancer. Purpose: This work outlines the development and performance evaluation of a methodology to absolutely quantify tumor 99m Tc activity uptake using a commercially available dual-headed MBI system by implementing corrections for background, scatter, attenuation, and detector characteristics. Methods: A validated Monte Carlo application of a commercial MBI system was used to simulate over 7000 unique acquisitions of spherical and ellipsoidal tumors in breast tissue. Tumor absolute activity was calculated following background, scatter, and attenuation corrections of tumor region of interest counts. The methodology was first optimized using a set of high-uptake spherical tumors, and its accuracy and precision was then assessed in a set of spherical tumors with clinical uptake conditions. Finally, the performance of the activity methodology was evaluated under various bias and uncertainty conditions to better characterize the technique under expected clinical measurement conditions. Results: In a test set of images with clinically relevant contrast and noise conditions, the mean ± standard deviation relative error in total tumor activity was 0.5% ± 6.5% (n = 2363) under ideal measurement conditions. Allowing for variability in tumor and background contours and in estimated tumor depths, the expected accuracy of the methodology in clinical practice was 0.5% ± 11.1% (n = 2363), with minimal loss of accuracy for ellipsoidal tumors. Conclusions: Planar MBI photopeak images acquired with standard-of -care protocols can be used to accurately quantify absolute tumor 99m Tc activity with an accuracy and precision of 0.5% ± 11.1%. The reported precision was based on a comprehensive evaluation of random errors and systematic biases.

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“…These simulations encompassed the broad range of clinically‐relevant breast compressed thicknesses (

{b}_z

), normal tissue uptake concentrations (

{C}_b

), spherical and ellipsoid tumor diameters (

{d}_x

{d}_y

{d}_z

), tumor distances from detectors (

{t}_z

), and tumor concentrations (

{C}_t

) observed in our practice with 99m Tc‐sestamibi imaging, as well as some extreme conditions for theoretical modeling. Compressed breasts were simulated by rectangular 15 by 15 by

{b}_z

Section: Methodsmentioning

confidence: 99%

“…Compressed breasts were simulated by rectangular 15 by 15 by b z cm ICRU-44 soft tissue block, ranging in thickness between 4 and 12 cm in 2 cm intervals. 7 In all acquisitions,the detector heads were placed along the zdimension immediately adjacent to the simulated breast (Figure 2).…”

Section: Monte Carlo Toolkit and Simulationsmentioning

confidence: 99%

Monte Carlo‐derived ^99mTc uptake quantification with commercial planar MBI: Absolute tumor activity

López

Kappadath

2023

Medical Physics

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“…Typical values for foam range from approximately 18–28%. We calculated the ideal % VA that an EVA foam sheet should possess to mimic the physical and dosimetric characteristics of the ICRU lung tissue by applying the Basic Data Method :

i d e a l % V A = \frac{{(μ / ρ)}_{ICRU} - {(μ / ρ)}_{E}}{{(μ / ρ)}_{VA} - {(μ / ρ)}_{E}} \times 100

where ( μ / ρ ) ICRU , ( μ / ρ ) E and ( μ / ρ ) VA are, respectively, the mass attenuation coefficients for the reference lung material (ICRU lung tissue), ethylene and vinyl acetate. We evaluated the previous expression in the energy range of 0.1–1 MeV.…”

Section: Methodsmentioning

confidence: 99%

“…EVA foam is available in sheets of different thicknesses and densities. The physical density of EVA foam sheets ranges from 0.030 to 0.965 g/cm 3 , almost covering the physical density range of the inflated/deflated lung (0.260–1.050 g/cm 3 ) . Note that the uncovered upper and lower density intervals are not very important because a completely deflated lung is never found in clinical practice.…”

Section: Introductionmentioning

confidence: 94%

Ethylene‐vinyl acetate foam as a new lung substitute in radiotherapy

Marqués

Mancha

2018

Medical Physics

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“…Each unique simulation was identified by 7 parameters: breast thickness in z-dimension (b z ), normal breast activity concentration (C b ), tumor diameters in x-dimension (d x ), y-dimension (d y ), and z-dimension (d z ), tumor center distance from detector (t z ), and tumor activity concentration (C t ). Simulated breasts were composed of ICRU-44 soft tissue [9], had thicknesses of 4-12 cm in 1 cm intervals, and had homogenous activity concentrations ranging from 0.185-4.44 kBq cm −3 (5-120 nCi cm −3 ).…”

Section: Simulated Data Setmentioning

confidence: 99%

Functional tumor diameter measurement with molecular breast imaging: development and clinical application

López¹,

Rauch²,

Adrada³

et al. 2022

Biomed. Phys. Eng. Express

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Purpose: Molecular breast imaging (MBI) is used clinically to visualize the uptake of 99mTc-sestamibi in breast cancers. Here, we use Monte Carlo simulations to develop a methodology to estimate tumor diameter in focal lesions and explore a semi-automatic implementation for clinical data. Methods: A validated Monte Carlo simulation of the GE Discovery NM 750b was used to simulate >75,000 unique spherical/ellipsoidal tumor, normal breast, and image acquisition conditions. Subsets of this data were used to 1) characterize the dependence of the full-width at half-maximum (FWHM) of a tumor profile on tumor, normal breast, and acquisition conditions, 2) develop a methodology to estimate tumor diameters, and 3) quantify the diameter accuracy in a broad range of clinical conditions. Finally, the methodology was implemented in patient images and compared to diameter estimates from physician contours on MBI, mammography, and ultrasound imaging. Results: Tumor profile FWHM was determined be linearly dependent on tumor diameter but independent of other factors such as tumor shape, uptake, and distance from the detector. A linear regression was used to calculate tumor diameter from the FWHM estimated from a background-corrected profile across a tumor extracted from a median-filtered single-detector MBI image, i.e., diameter = 1.2 mm + 1.2 x FWHM, for FWHM ≥ 13 mm. Across a variety of simulated clinical conditions, the mean error of the methodology was 0.2 mm (accuracy), with >50% of cases estimated within 1-pixel width of the truth (precision). In patient images, the semi-automatic methodology provided the longest diameter in 94% (60/64) of cases. The estimated true diameters, for oval lesions with homogeneous uptake, differed by ± 5 mm from physician measurements. Conclusion: This work demonstrates the feasibility of accurately quantifying tumor diameter in clinical MBI, and to our knowledge, is the first to explore its implementation and application in patient data.

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3. Selection Requirements for Tissue Substitutes

Cited by 14 publications

References 0 publications

Monte Carlo‐derived ^99mTc uptake quantification with commercial planar MBI: Absolute tumor activity

Monte Carlo‐derived ^99mTc uptake quantification with commercial planar MBI: Absolute tumor activity

Ethylene‐vinyl acetate foam as a new lung substitute in radiotherapy

Functional tumor diameter measurement with molecular breast imaging: development and clinical application

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3. Selection Requirements for Tissue Substitutes

Cited by 14 publications

References 0 publications

Monte Carlo‐derived 99mTc uptake quantification with commercial planar MBI: Absolute tumor activity

Monte Carlo‐derived 99mTc uptake quantification with commercial planar MBI: Absolute tumor activity

Ethylene‐vinyl acetate foam as a new lung substitute in radiotherapy

Functional tumor diameter measurement with molecular breast imaging: development and clinical application

Contact Info

Product

Resources

About

Monte Carlo‐derived ^99mTc uptake quantification with commercial planar MBI: Absolute tumor activity

Monte Carlo‐derived ^99mTc uptake quantification with commercial planar MBI: Absolute tumor activity