Reduce in variation and improve efficiency of target volume delineation by a computer-assisted system using a deformable image registration approach.
OBJECTIVE
To determine whether a computer-assisted target volume delineation (CAT) system using a deformable image registration approach can reduce the variation of target delineation among physicians with different head and neck (HN) IMRT experiences and reduce the time spent on the contouring process.


METHODS
We developed a deformable image registration method for mapping contours from a template case to a patient case with a similar tumor manifestation but different body configuration. Eight radiation oncologists with varying levels of clinical experience in HN IMRT performed target delineation on two HN cases, one with base-of-tongue (BOT) cancer and another with nasopharyngeal cancer (NPC), by first contouring from scratch and then by modifying the contours deformed by the CAT system. The gross target volumes were provided. Regions of interest for comparison included the clinical target volumes (CTVs) and normal organs. The volumetric and geometric variation of these regions of interest and the time spent on contouring were analyzed.


RESULTS
We found that the variation in delineating CTVs from scratch among the physicians was significant, and that using the CAT system reduced volumetric variation and improved geometric consistency in both BOT and NPC cases. The average timesaving when using the CAT system was 26% to 29% for more experienced physicians and 38% to 47% for the less experienced ones.


CONCLUSIONS
A computer-assisted target volume delineation approach, using a deformable image-registration method with template contours, was able to reduce the variation among physicians with different experiences in HN IMRT while saving contouring time.
Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX 7030, USA. cchao@mdanderson.org
K S Clifford
KS
Chao
Shreerang
S
Bhide
Hansen
H
Chen
Joshua
J
Asper
Steven
S
Bush
Gregg
G
Franklin
Vivek
V
Kavadi
Vichaivood
V
Liengswangwong
William
W
Gordon
Adam
A
Raben
Jon
J
Strasser
Christopher
C
Koprowski
Steven
S
Frank
Gregory
G
Chronowski
Anesa
A
Ahamad
Robert
R
Malyapa
Lifei
L
Zhang
Lei
L
Dong
D004526:Efficiency; D006801:Humans; D008495:Medical Oncology / Q000592:standards*; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011859:Radiography; D011880:Radiotherapy Planning, Computer-Assisted; D014062:Tongue Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D047368:Tumor Burden