PMID- 11483349
OWN - NLM
STAT- MEDLINE
DCOM- 20010906
LR  - 20191210
IS  - 0360-3016 (Print)
IS  - 0360-3016 (Linking)
VI  - 50
IP  - 5
DP  - 2001 Aug 1
TI  - Variability in target volume delineation on CT scans of the breast.
PG  - 1366-72
AB  - PURPOSE: To determine the intra- and interobserver variation in delineation of 
      the target volume of breast tumors on computed tomography (CT) scans in order to 
      perform conformal radiotherapy. MATERIALS AND METHODS: The clinical target volume 
      (CTV) of the breast was delineated in CT slices by four radiation oncologists on 
      our clinically used delineation system. The palpable glandular breast tissue was 
      marked with a lead wire on 6 patients before CT scanning, whereas 4 patients were 
      scanned without a lead wire. The CTV was drawn by each observer on three separate 
      occasions. Planning target volumes (PTVs) were constructed by expanding the CTV 
      by 7 mm in each direction, except toward the skin. The deviation in the PTV 
      extent from the average extent was quantified in each orthogonal direction for 
      each patient to find a possible directional dependence in the observer 
      variations. In addition, the standard deviation of the intra- and interobserver 
      variation in the PTV volume was quantified. For each patient, the common volumes 
      delineated by all observers and the smallest volume encompassing all PTVs were 
      also calculated. RESULTS: The patient-averaged deviations in PTV extent were 
      larger in the posterior (42 mm), cranial (28 mm), and medial (24 mm) directions 
      than in the anterior (6 mm), caudal (15 mm), and lateral (8 mm) directions. The 
      mean intraobserver variation in volume percentage (5.5%, 1 SD) was much smaller 
      than the interobserver variation (17.5%, 1 SD). The average ratio between the 
      common and encompassing volume for the four observers separately was 0.82, 0.74, 
      0.82, and 0.80. A much lower combined average ratio of 0.43 was found because of 
      the large interobserver variations. For the observer who placed the lead wire, 
      the intraobserver variation in volume was decreased by a factor of 4 on scans 
      made with a lead wire in comparison to scans made without a lead wire. For the 
      other observers, no improvement was seen. Based on these results, an improved 
      delineation protocol was designed. CONCLUSIONS: Intra- and especially 
      interobserver variation in the delineation of breast target volume on CT scans 
      can be rather large. A detailed delineation protocol making use of CT scans with 
      lead wires placed on the skin around the palpable breast by the delineating 
      observer reduces the intraobserver variation. To reduce the interobserver 
      variation, better imaging techniques and pathology studies relating glandular 
      breast tissue to imaging may be needed to provide more information on the extent 
      of the clinical target volume.
FAU - Hurkmans, C W
AU  - Hurkmans CW
AD  - Department of Radiotherapy, The Netherlands Cancer Institute/Antoni van 
      Leeuwenhoek Hospital, Amsterdam, The Netherlands.
FAU - Borger, J H
AU  - Borger JH
FAU - Pieters, B R
AU  - Pieters BR
FAU - Russell, N S
AU  - Russell NS
FAU - Jansen, E P
AU  - Jansen EP
FAU - Mijnheer, B J
AU  - Mijnheer BJ
LA  - eng
PT  - Comparative Study
PT  - Evaluation Study
PT  - Journal Article
PL  - United States
TA  - Int J Radiat Oncol Biol Phys
JT  - International journal of radiation oncology, biology, physics
JID - 7603616
SB  - IM
MH  - Breast Neoplasms/*diagnostic imaging/pathology/radiotherapy
MH  - Female
MH  - Humans
MH  - Mammography/instrumentation/*methods
MH  - *Observer Variation
MH  - Radiotherapy, Conformal
MH  - Reproducibility of Results
MH  - *Tomography, X-Ray Computed
EDAT- 2001/08/03 10:00
MHDA- 2001/09/08 10:01
CRDT- 2001/08/03 10:00
PHST- 2001/08/03 10:00 [pubmed]
PHST- 2001/09/08 10:01 [medline]
PHST- 2001/08/03 10:00 [entrez]
AID - S0360301601016352 [pii]
AID - 10.1016/s0360-3016(01)01635-2 [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 2001 Aug 1;50(5):1366-72. doi: 
      10.1016/s0360-3016(01)01635-2.