Document Type : Original Paper
Physics Department, Faculty of Science, Zagazig University, Zagazig, Egypt.
Clinical Oncology and Nuclear Medicine Department, Faculty of Medicine, El-Azhar University, Cairo, Egypt
Clinical Oncology and Nuclear Medicine Department, Faculty of Medicine, ZagazigUniversity, Zagazig, Egypt.
Radiation Oncology Department, International Medical Center (IMC), Egypt.
Clinical Oncology and Nuclear Medicine department, Zagazig University Hospitals, Egypt.
Introduction: stereotactic body radiotherapy (SBRT)is the most proper treatment for multi lesions
non-small cell lung cancer (NSCLC) for enhanced good coverage and minimizing dose to organs
at risk (OARs). This study aims to compare single and dual isocenter SBRT plans and discuss
which technique we can use in multi lesions NSCLC with a maximum distance between two
lesions was 10cm and maximum planning target volumes was 90cc.
Material and Methods: ten patients with multi targets NSCLC underwent two different SBRT
treatment planning techniques including single isocenter and dual isocenter. We quantitatively
assessed plan qualities by dose-volume metrics. Conformity index (CI), Confirmation Number
(CN), heterogeneity index (HI), gradient distance (GD), Gradient index (GI), and maximum dose
at 2cm all around PTV (𝐷2𝑐𝑚) were calculated. OARs were evaluated and the dose to the normal
lung was evaluated using V5, V10, V20, and mean lung dose (MLD).
Results: There is an insignificant difference between single and dual isocenter plans in CI, CN,
HI, GD, GI, and dose spillage where the mean distance between two lesions was 5.50 ± 1.50 cm,
and the mean total volume of the planning target volume (PTV) was 42.60±21.33cc. For single
and dual isocenter plans, the mean MLD was 5.70 ± 4.13 Gy and 6.50 ± 4.76Gy respectively.
Conclusion: Plan quality of single isocenter was equal to dual isocenter for SBRT treatment of
multi lung lesions with maximum distances between them was 10 cm. dual isocenter took time
during setup and matching for CBCT.