Publications

3

Research at the intersection of machine learning, mathematical optimization, and medical imaging — designing and evaluating multiplexed SPECT systems through physics simulation, Bayesian optimization, and artifact quantification.

Google Scholar
Assess SPECT System's Pixel-wise Tomographic Resolution through Analysis of Projection Probability Density Function
Siddharth Mehta, Avantika Guleria, Fang Han, Harsh Tripathi, Tridev Methuku, Tianyu Ma, Rutao Yao
SPIE Medical Imaging 2026 — Physics of Medical Imaging
2026 • Conference • First author

Connects detector geometry directly to image quality by deriving pixel-wise tomographic resolution from projection probability density functions (PPDFs) — an analytical ray-tracing model that produces a per-pixel resolution map, so system performance can be evaluated quantitatively before any hardware is built.

A Quantitative Framework for Optimizing Multi-Pinhole and Self-Collimating SPECT Design
Harsh Tripathi, Siddharth Mehta, Avantika Guleria, Tessa Skirsky, Omer Shah, Leslie Ying, Rutao Yao
Journal of Nuclear Medicine
2026 • Journal

Casts SPECT detector design as a search over a parameterized geometry space: analytical ray-tracing yields per-pixel resolution, angular-sampling-completeness, and sensitivity maps for each candidate design, and a joint index (sensitivity × completeness / resolution²) ranks them — replacing trial-and-error engineering with metric-driven optimization.

Quantifying Multiplexing-Induced Ghost Artifact via a Projection Sampling Similarity Index in SPECT
Siddharth Mehta, Avantika Guleria, Harsh Tripathi, Tridev Methuku, Tessa Skirsky, Omer Shah, Tianyu Ma, Rutao Yao
Journal of Nuclear Medicine
2026 • Journal • First author

Multiplexed pinholes share sampling across pixels, so activity at one location can geometrically "ghost" into symmetric locations in the reconstruction. We define a multiplexing similarity index over the system's projection sampling patterns — the fraction of projection beams shared between two pixels — turning ghost-artifact risk into a quantitative, per-pixel geometry metric computable before any data is acquired.