Inhomogeneity correction in radiotherapy for lung cancer in multicenter clinical trials.
OBJECTIVE
Dose distribution in patients in past multicenter clinical trials was reviewed from the perspective of clinicians to evaluate the quality of treatment and to improve the quality of future clinical trials.


METHODS
Thirty patients with stage III lung cancer, who had undergone radical radiation therapy in multicenter clinical trials were retrospectively reviewed. A two-dimensional treatment planning system using Clarkson integration was used to calculate correction factors at the primary lesions and at the mediastinal lymph nodes.


RESULTS
Correction factors at the primary lesions ranged from 1.00 to 1.12 (mean, 1.06) and from 1.02 to 1.14 (mean, 1.06) in the AP/PA fields and in the oblique fields, respectively. The lowest values of correction factors at the mediastinal lymph nodes on the axial plane including the primary lesions ranged from 0.93 to 1.04 (mean, 0.98) and from 0.97 to 1.10 (mean, 1.02) in the AP/PA fields and in the oblique fields, respectively. In 14 patients whose primary tumor was located in the upper lung field, the correction factors at the subcarinal lymph nodes ranged from 0.90 to 1.01 (mean, 0.96) in the AP/PA fields.


CONCLUSIONS
Delivered doses lower than those prescribed at the mediastinal lymph nodes should be taken into consideration to improve the quality of multicenter clinical trials.
Tada
Takuhito
T
Department of Radiology, Osaka Prefectural Habikino Hospital, Japan.
Minakuchi
Kazuo
K
Sakamoto
Hisashi
H
Fukuda
Haruyuki
H
Bun
Mineyoshi
M
Nakajima
Toshifumi
T
D002986:Clinical Trials as Topic; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008198:Lymph Nodes / Q000528:radiation effects; D015337:Multicenter Studies as Topic; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D011882:Radiotherapy, High-Energy; D012189:Retrospective Studies