Radiotherapy of large target volumes in Hodgkin's lymphoma: normal tissue sparing capability of forward IMRT versus conventional techniques.
BACKGROUND
This paper analyses normal tissue sparing capability of radiation treatment techniques in Hodgkin's lymphoma with large treatment volume.


METHODS
10 patients with supradiaphragmatic Hodgkin's lymphoma and planning target volume (PTV) larger than 900 cm3 were evaluated. Two plans were simulated for each patient using 6 MV X-rays: a conventional multi-leaf (MLC) parallel-opposed (AP-PA) plan, and the same plan with additional MLC shaped segments (forward planned intensity modulated radiation therapy, FPIMRT). In order to compare plans, dose-volume histograms (DVHs) of PTV, lungs, heart, spinal cord, breast, and thyroid were analyzed. The Inhomogeneity Coefficient (IC), the PTV receiving 95% of the prescription dose (V95), the normal tissue complication probability (NTCP) and dose-volume parameters for the OARs were determined.


RESULTS
the PTV coverage was improved (mean V95AP-PA=95.9 and ICAP-PA=0.4 vs. V95FPIMRT=96.8 and ICFPIMRT=0.31, p<or=0.05) by the FPIMRT technique compared to the conventional one. At the same time, NTCPs of lung, spinal cord and thyroid, and the volume of lung and thyroid receiving>or=30 Gy resulted significantly reduced when using the FPIMRT technique.


CONCLUSIONS
The FPIMRT technique can represent a very useful and, at the same time, simple method for improving PTV conformity while saving critical organs when large fields are needed as in Hodgkin's lymphoma.
Cella
Laura
L
Institute of Biostructures and Bioimages, National Council of Research (CNR), Via Pansini 5, 80131, Naples, Italy.
Liuzzi
Raffaele
R
Magliulo
Mario
M
Conson
Manuel
M
Camera
Luigi
L
Salvatore
Marco
M
Pacelli
Roberto
R
D000328:Adult; D001940:Breast / Q000528:radiation effects*; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006689:Hodgkin Disease / Q000532:radiotherapy*; D006801:Humans; D008168:Lung / Q000528:radiation effects*; D008297:Male; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D013116:Spinal Cord / Q000528:radiation effects*; D013961:Thyroid Gland / Q000528:radiation effects*; D055815:Young Adult
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