Dosimetric comparison of three different involved nodal irradiation techniques for stage II Hodgkin's lymphoma patients: conventional radiotherapy, intensity-modulated radiotherapy, and three-dimensional proton radiotherapy.
OBJECTIVE
To compare the dose distribution to targeted and nontargeted tissues in Hodgkin's lymphoma patients using conventional radiotherapy (CRT), intensity-modulated RT (IMRT), and three-dimensional proton RT (3D-PRT).


METHODS
CRT, IMRT, and 3D-PRT treatment plans delivering 30 cobalt Gray equivalent (CGE)/Gy to an involved nodal field were created for 9 Stage II Hodgkin's lymphoma patients (n = 27 plans). The dosimetric endpoints were compared.


RESULTS
The planning target volume was adequately treated using all three techniques. The IMRT plan produced the most conformal high-dose distribution; however, the 3D-PRT plan delivered the lowest mean dose to nontarget tissues, including the breast, lung, and total body. The relative reduction in the absolute lung volume receiving doses of 4-16 CGE/Gy for 3D-PRT compared with CRT ranged from 26% to 37% (p < .05), and the relative reduction in the absolute lung volume receiving doses of 4-10 CGE/Gy for 3D-PRT compared with IMRT was 48-65% (p < .05). The relative reduction in absolute total body volume receiving 4-30 CGE/Gy for 3D-PRT compared with CRT was 47% (p < .05). The relative reduction in absolute total body volume receiving a dose of 4 CGE/Gy for 3D-PRT compared with IMRT was 63% (p = .03). The mean dose to the breast was significantly less for 3D-PRT than for either IMRT or CRT (p = .03) The mean dose and absolute volume receiving 4-30 CGE/Gy for the heart, thyroid, and salivary glands were similar for the three modalities.


CONCLUSIONS
In this favorable subset of Hodgkin's lymphoma patients without disease in or below the hila, 3D-PRT significantly reduced the dose to the breast, lung, and total body. These observed dosimetric advantages might improve the clinical outcomes of Hodgkin's lymphoma patients by reducing the risk of late radiation effects related to low-to-moderate doses in nontargeted tissues.
Chera
Bhishamjit S
BS
Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL 32206, USA.
Rodriguez
Christina
C
Morris
Christopher G
CG
Louis
Debbie
D
Yeung
Daniel
D
Li
Zuofeng
Z
Mendenhall
Nancy P
NP
D001940:Breast / Q000528:radiation effects; D005260:Female; D006321:Heart / Q000528:radiation effects; D006689:Hodgkin Disease / Q000188:drug therapy / Q000532:radiotherapy*; D006801:Humans; D008168:Lung / Q000528:radiation effects; D015182:Lymphatic Irradiation / Q000379:methods*; D008297:Male; D008482:Mediastinum; D009333:Neck; D061766:Proton Therapy; D011832:Radiation Injuries / Q000517:prevention & control; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D012469:Salivary Glands / Q000528:radiation effects; D013961:Thyroid Gland / Q000528:radiation effects; D047368:Tumor Burden; D011522:Protons
D011522:Protons