Semiautomatic technique for defining the internal gross tumor volume of lung tumors close to liver/spleen cupola by 4D-CT.
OBJECTIVE
It has been shown that in cases of lung tumors close to the liver cupola, the four dimensional (4D)-CT postprocessing maximum intensity projection (MIP) algorithm does not fully recover the radiotherapy internal gross tumor volume (IGTV). In this work, a semiautomatic technique was evaluated by which the residual IGTV that was not included into the IGTV by MIP algorithm was actually added.


METHODS
A moving phantom and five selected patients were considered. The various IGTVs produced by the semiautomatic approach were compared to those generated by 4D-CT manual contouring.


RESULTS
In all cases, the radiation oncologist qualitatively concurred with the semiautomatic IGTV. A quantitative difference in volume of 2.6% was found in the phantom study, whereas a mean difference of 0.1 +/- 4.6% was obtained in the patient studies.


CONCLUSIONS
A semiautomatic technique to include the residual part of IGTV covered by liver/spleen cupola when using MIP algorithm was validated on phantom and on selected patients, revealing the possibility of defining the IGTV for patients with lesions located near liver/spleen cupola by performing only the contours on the MIP series.
Department of Radiotherapy, IRCCS Istituto Clinico Humanitas, Rozzano, 20089 Milano, Italy. pietro.mancosu@humanitas.it
Pietro
P
Mancosu
Roberto
R
Sghedoni
Valentino
V
Bettinardi
Mark Anthony
MA
Aquilina
Piera
P
Navarria
Giovanni Mauro
GM
Cattaneo
Nadia
N
Di Muzio
Luca
L
Cozzi
Marta
M
Scorsetti
D000465:Algorithms; D001331:Automation; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008099:Liver; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D013154:Spleen; D047368:Tumor Burden