Dosimetric Comparative Study between Single and Dual Isocenter Stereotactic Body Radiotherapy Plans in Treatment of Multiple Lesions Non-Small Cell Lung Cancer Patients.

Document Type : Original Paper


1 Physics Department, Faculty of Science, Zagazig University, Zagazig, Egypt.

2 Clinical Oncology and Nuclear Medicine Department, Faculty of Medicine, El-Azhar University, Cairo, Egypt

3 Clinical Oncology and Nuclear Medicine Department, Faculty of Medicine, ZagazigUniversity, Zagazig, Egypt.

4 Radiation Oncology Department, International Medical Center (IMC), Egypt.

5 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.


Main Subjects

Articles in Press, Accepted Manuscript
Available Online from 11 June 2022
  • Receive Date: 11 January 2022
  • Revise Date: 04 June 2022
  • Accept Date: 11 June 2022
  • First Publish Date: 11 June 2022