Seminars IFIC

se-fis-med: Post-therapy 131-I dose quantification based on quality image enhancement

by Andrea Abril Fajardo

1001-Primera-1-1-1 - Paterna. Seminario (Universe)

1001-Primera-1-1-1 - Paterna. Seminario


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Medical Physics Seminar - Seminario de Física Médica


Author: Andrea Abril Fajardo, PhD


Profesora Asistente
Departamento de Física
Universidad Nacional de Colombia

Profesora Asistente, Departamento de Física
Coordinadora Maestría en Física Médica
Pontificia Universidad Javeriana



The dosimetry in target radionuclide therapy, as a potential quality assortment of the delivered treatment, is a crucial aspect of clinical practice. Standardizing this, especially in low and middle-income regions, is a challenge due to the economic resources needed to acquire specialized software. Our research proposes a step-based analysis that could serve as a quality management task, offering a practical solution to this challenge and contributing to a better understanding of radiopharmaceutical therapies.

A typical task in posttherapy targeted radionuclide therapy is determining the uptake in tumours, lesions, or organ evolution through SPECT images. Several factors can affect the relationship between the administered activity and the counting activity in the image: collimator selection, contribution to scattering photons, and windows level strongly influence the image's human observer performance or computer performance studies. A quantification dosimetry method is presented, based on the previous planar spatial resolution and thickness analysis using the Jaszczak SPECT phantom line inserts and traduced in better organ definition contribution on the image; the methodology is based on function reduction of scatter counts defining a specific FWHM and a final correlation between the activity at the target organ. This work analyses the internal dosimetry workflow on a thyroid lesion since Jaszczak inserts three-axial resolution and post-processing contrast enhancement and applies statistical criteria to define the line spread function with the initial activity.

As a result, a calibration function is obtained in the activity uptake to be applied in the dose calculations of the target organ due to only pixel-by-pixel counts information and in a three-dimensional reconstruction with the SPECT slices and specific fractions for the organs observed in the images. 


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Organized by

Ana Ros y Fernando Hueso