Sci—Thurs PM: Planning—07: Impact of Quantitative SPECT Corrections on SPECT‐Weighted Mean Dose and Functional Lung Volume Segmentation as Applied in Functional Sparing RT Planning

• Published in: Medical Physics 2009-09, Vol.36 (9), p.4319-4319
• Main Authors: Yin, L, Celler, A, Shcherbinin, S, Moiseenko, V, Fua, T‐F, Thompson, A, Liu, M, Duzenli, C, Gill, B, Sheehan, F, Powe, J, Worsley, D
• Format: Article
• Language: English
• Subjects: Cancer; Image reconstruction; Iteration theory; Lungs; Medical image reconstruction; Medical imaging; Medical treatment planning; Single photon emission computed tomography
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.3244178

Purpose: To compare functional lung volume segmentation and Single Photon Emission Computed Tomography (SPECT) weighted mean dose (SWMD) approaches used in SPECT guided treatment planning studies for patients with lung cancer. Methods and Materials: Nine lung cancer patients were consented to have a perfusion SPECT scan with 99mTc‐macroaggregated albumin. Four image sets were reconstructed from each scan: one using a vendor provided ordered subsets expectation maximization (OSEM) algorithm and three quantitative SPECT reconstructions using OSEM methods with different types of attenuation and scatter corrections. SWMDs were calculated for open field with different sizes and gantry angles. Functional lung volumes were segmented in each reconstructed image using 10, 20, …, 90% of maximum SPECT intensity as a threshold. Results: Image reconstruction accuracy and thus functional lung volume segmentation are affected by several factors, such as attenuation and scatter correction, resolution recovery method and number of iterations used in reconstruction. Large differences in functional volumes (more than 50%) were found between images obtained from the four reconstructions. In contrast, the SWMD calculation produced consistent results for all SPECT reconstructions which included attenuation correction, regardless of whether or not scatter correction was used and the number of iterations. Conclusion: Functional volume segmentation is sensitive to the type of attenuation and scatter correction and number of iterations. In contrast, for images reconstructed with attenuation correction, the SWMD calculation produces consistent results and appears to be a more robust choice to be used in future studies incorporating SPECT into treatment planning.