Investigation of the impact of tumor volume and tumor proximity on dosimetry in scintigraphic imaging of the liver: A phantom study
Abstract
Objective: This study aims to evaluate the impact of tumor volume variation and tumor proximity on scintigraphic image quality and dosimetry, and to objectively analyze these effects using contrast and contrast-to-noise ratio (CNR) parameters.
Materials and Methods: A specially designed liver phantom containing four simulated tumors with diameters of 1 cm, 2 cm, 3 cm, and 5 cm was used. The tumors and the surrounding liver parenchyma-mimicking areas were filled with ⁹⁹ᵐTc at a ratio of 4.88:1. The phantom was imaged in a water tank using standard clinical protocols for both planar and SPECT scintigraphy. Contrast and CNRs were calculated from regions of interest (ROI).
Results: In SPECT images, as tumor diameter increased, tumor-to-normal liver ratio (T/N) per milliliter, contrast, CNR, and tumor doses also increased. Tumor doses for 1 cm and 5 cm diameter lesions were found to be 6.9 Gy/ml and 13.43 Gy/ml, respectively.
Conclusion: This study analyzed the mutual effect of ROI counts in the presence of small and multiple tumors in ⁹⁹ᵐTc-MAA pre-dosimetry for liver tumors. It was observed that smaller tumors (1–3 cm) located near larger tumors were affected by spillover from the larger lesions, resulting in artificially elevated ROI counts and consequently overestimated dose calculations. In conclusion, the presence of larger lesions may influence dosimetric evaluations of smaller (1–3 cm) tumors, potentially leading to inaccurate dose assessments.
References
- 1. Chiesa C, Sjogreen-Gleisner K, Walrand S, Strigari L, Flux G, Gear J, et al. EANM dosimetry committee series on standard operational procedures: a unified methodology for 99mTc-MAA pre- and 90Y peri-therapy dosimetry in liver radioembolization with 90Y microspheres. EJNMMI Phys 2021;8:1–44.
- 2. Grikke L, De Giorgio M, Bianchi C, Balduzzi E, Carbone FS, Gerali A, et al. Dosimetric optimization and evaluation of hepatocellular carcinoma treatment effect prediction in Y-90 radioembolization. Phys Med 2025;134:105000.
- 3. Buvat I, Benali H. Modeling noise properties of 99mTc SPECT images: consequences for quantitation and image reconstruction. J Nucl Med 2002;43(8):1235–41.
- 4. Shcherbinin S, Celler A, Belhocine T, Vanderwerf R, Driedger A. Accuracy of quantitative reconstructions in SPECT/CT imaging. Phys Med Biol 2008;53(17):4595.
- 5. Karakatsanis NA, Lodge MA, Rahmim A. Quantitative performance of contrast-to-noise ratio metrics in nuclear medicine imaging. Phys Med Biol 2013;58(13):4495–510.
- 6. Zaidi H, Hasegawa B. Determination of the optimum energy window for PET imaging using contrast and CNR analysis. Med Phys 2003;30(6):1307–13.
- 7. Beyer T, Townsend DW, Brun T, Kinahan PE, Charron M, Roddy R, et al. A combined PET/CT scanner for clinical oncology. J Nucl Med 2000;41(8):1369–79.
- 8. Iball GR, Kennedy EV, Brettle DS. Phantom-based comparison of image quality for planar and tomographic 99mTc imaging. Br J Radiol 2012;85(1012):1040–6.
- 9. Yeyin N, Kesmezacar FF, Tunçman D, Demir Ö, Uslu-Beşli L, Günay O, et al. Hepatopulmonary shunt ratio verification model for transarterial radioembolization. Curr Radiopharm 2024;17(3):276–84.
- 10. Dickerscheid D, Lavalaye J, Romijn L, Habraken J. Contrast-noise-ratio (CNR) analysis and optimisation of breast-specific gamma imaging (BSGI) acquisition protocols. EJNMMI Res 2021;3:1–9.
- 11. Dezarn WA, Cessna JT, DeWerd LA, Feng W, Gates VL, Halama J, et al. Recommendations of the American Association of Physicists in Medicine on dosimetry, imaging, and quality assurance procedures for 90Y microsphere brachytherapy in the treatment of hepatic malignancies. Med Phys 2011;38(8):4824–45.
- 12. Soret M, Bacharach SL, Buvat I. Partial Volume Effect in PET Tumor Imaging. J Nucl Med 2007;48(6):932-45.
- 13. Son MH. Diagnostic and prognostic value of 99mTc-MAA SPECT/CT for treatment planning of 90Y resin microsphere radioembolization for hepatocellular carcinoma: comparison with planar image. Sci Rep 2021;11:3207.
- 14. Glatting G, Landmann M, Wunderlich A, Kull T, Mottaghy FM, Reske SN, et al. Internal radionuclide therapy. Nuklearmedizin 2006;45(6):269–72.
- 15. Zasadny KR, Wahl RL. Standardized uptake values of normal tissues at PET with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose: variations with body weight and a method for correction. Radiology 1995;189(3):847–50.
- 16. Soret M, Bacharach SL, Buvat I. Partial-volume effect in PET tumor imaging. J Nucl Med 2007;48(6):932–45.
- 17. Boellaard R. Standards for PET image acquisition and quantitative data analysis. J Nucl Med 2009;50(Suppl 1):11S–20S.
Karaciğerin sintigrafik görüntülenmesinde tümör hacmi ve tümör yakınlığının dozimetriye etkisinin incelenmesi: Fantom çalışması
Abstract
Amaç: Bu çalışma, tümör hacmi değişkenliği ve tümörlerin birbirine yakınlığının sintigrafik görüntü kalitesi ve dozimetrik hesaplamalar üzerindeki etkilerini değerlendirmeyi ve bu etkileri kontrast ile kontrast-gürültü oranı (CNR) parametreleri kullanarak nesnel biçimde analiz etmeyi amaçlamaktadır.
Gereç ve Yöntem: Dört adet 1 cm, 2 cm, 3 cm ve 5 cm çapında taklit tümör içeren özel olarak tasarlanmış bir karaciğer fantomu kullanılmıştır. Tümörler ve çevresindeki karaciğer parankim dokusunu taklit eden bölgeler, ⁹⁹ᵐTc ile 4,88:1 oranında doldurulmuştur. Fantom, su tankı içerisinde hem planar hem de SPECT sintigrafisi için standart klinik protokoller uygulanarak görüntülenmiştir. Kontrast ve CNR değerleri, ilgi alanı bölgelerinden (ROI) hesaplanmıştır.
Bulgular: SPECT görüntülerinde, tümör çapı arttıkça, mililitre başına tümör/normal karaciğer oranı (T/N), kontrast, CNR ve tümör dozları da artmıştır. Çapı 1 cm ve 5 cm olan lezyonlar için tümör dozları sırasıyla 6,9 Gy/ml ve 13,43 Gy/ml olarak bulunmuştur.
Sonuç: Bu çalışmada, karaciğer tümörlerine yönelik ⁹⁹ᵐTc-MAA predosimetri uygulamalarında küçük ve çoklu tümörlerin varlığında ROI sayımlarının karşılıklı etkileri analiz edilmiştir. Küçük çaplı (1–3 cm) tümörlerin, daha büyük tümörlere yakın konumlandığında büyük lezyonlardan kaynaklanan “spillover” etkisi ile yapay olarak yüksek ROI sayımları gösterdiği ve buna bağlı olarak doz hesaplamalarının olduğundan yüksek tahmin edildiği gözlenmiştir. Sonuç olarak, büyük lezyonların varlığı, küçük (1–3 cm) tümörlerin dozimetrik değerlendirmelerini etkileyerek hatalı doz tahminlerine yol açabilmektedir.
References
- 1. Chiesa C, Sjogreen-Gleisner K, Walrand S, Strigari L, Flux G, Gear J, et al. EANM dosimetry committee series on standard operational procedures: a unified methodology for 99mTc-MAA pre- and 90Y peri-therapy dosimetry in liver radioembolization with 90Y microspheres. EJNMMI Phys 2021;8:1–44.
- 2. Grikke L, De Giorgio M, Bianchi C, Balduzzi E, Carbone FS, Gerali A, et al. Dosimetric optimization and evaluation of hepatocellular carcinoma treatment effect prediction in Y-90 radioembolization. Phys Med 2025;134:105000.
- 3. Buvat I, Benali H. Modeling noise properties of 99mTc SPECT images: consequences for quantitation and image reconstruction. J Nucl Med 2002;43(8):1235–41.
- 4. Shcherbinin S, Celler A, Belhocine T, Vanderwerf R, Driedger A. Accuracy of quantitative reconstructions in SPECT/CT imaging. Phys Med Biol 2008;53(17):4595.
- 5. Karakatsanis NA, Lodge MA, Rahmim A. Quantitative performance of contrast-to-noise ratio metrics in nuclear medicine imaging. Phys Med Biol 2013;58(13):4495–510.
- 6. Zaidi H, Hasegawa B. Determination of the optimum energy window for PET imaging using contrast and CNR analysis. Med Phys 2003;30(6):1307–13.
- 7. Beyer T, Townsend DW, Brun T, Kinahan PE, Charron M, Roddy R, et al. A combined PET/CT scanner for clinical oncology. J Nucl Med 2000;41(8):1369–79.
- 8. Iball GR, Kennedy EV, Brettle DS. Phantom-based comparison of image quality for planar and tomographic 99mTc imaging. Br J Radiol 2012;85(1012):1040–6.
- 9. Yeyin N, Kesmezacar FF, Tunçman D, Demir Ö, Uslu-Beşli L, Günay O, et al. Hepatopulmonary shunt ratio verification model for transarterial radioembolization. Curr Radiopharm 2024;17(3):276–84.
- 10. Dickerscheid D, Lavalaye J, Romijn L, Habraken J. Contrast-noise-ratio (CNR) analysis and optimisation of breast-specific gamma imaging (BSGI) acquisition protocols. EJNMMI Res 2021;3:1–9.
- 11. Dezarn WA, Cessna JT, DeWerd LA, Feng W, Gates VL, Halama J, et al. Recommendations of the American Association of Physicists in Medicine on dosimetry, imaging, and quality assurance procedures for 90Y microsphere brachytherapy in the treatment of hepatic malignancies. Med Phys 2011;38(8):4824–45.
- 12. Soret M, Bacharach SL, Buvat I. Partial Volume Effect in PET Tumor Imaging. J Nucl Med 2007;48(6):932-45.
- 13. Son MH. Diagnostic and prognostic value of 99mTc-MAA SPECT/CT for treatment planning of 90Y resin microsphere radioembolization for hepatocellular carcinoma: comparison with planar image. Sci Rep 2021;11:3207.
- 14. Glatting G, Landmann M, Wunderlich A, Kull T, Mottaghy FM, Reske SN, et al. Internal radionuclide therapy. Nuklearmedizin 2006;45(6):269–72.
- 15. Zasadny KR, Wahl RL. Standardized uptake values of normal tissues at PET with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose: variations with body weight and a method for correction. Radiology 1995;189(3):847–50.
- 16. Soret M, Bacharach SL, Buvat I. Partial-volume effect in PET tumor imaging. J Nucl Med 2007;48(6):932–45.
- 17. Boellaard R. Standards for PET image acquisition and quantitative data analysis. J Nucl Med 2009;50(Suppl 1):11S–20S.
Details
| Primary Language | English |
|---|---|
| Subjects | Medical Education |
| Journal Section | Research Article |
| Authors | |
| Submission Date | September 1, 2025 |
| Acceptance Date | October 22, 2025 |
| Publication Date | December 31, 2025 |
| Published in Issue | Year 2025 Volume: 47 Issue: 4 |