PMID- 20941815
OWN - NLM
STAT- MEDLINE
DCOM- 20101221
LR  - 20101013
IS  - 1107-0625 (Print)
IS  - 1107-0625 (Linking)
VI  - 15
IP  - 3
DP  - 2010 Jul-Sep
TI  - External beam radiotherapy of bladder carcinoma: considerations in determining 
      the irradiation field margins.
PG  - 489-95
AB  - PURPOSE: Motions of the bladder and rectum during pelvic irradiation are 
      considered as major causes of geometrical uncertainties. As a result, the volume 
      status of these organs is changed and the definition of the treatment margins is 
      imperative. The aim of this study was, firstly, to determine these margins, 
      comparing series of CT scans, performed at simulation time, with empty (EB) and 
      full bladder (FB) and, secondly, to evaluate the dose volume histograms (DVHs) of 
      tumor and rectum using standard treatment margins. METHODS: Fifteen patients with 
      muscle-invading urinary bladder carcinoma underwent two scan series with EB and 
      FB bladder during radiotherapy (RT) simulation. Gross tumor volume (GTV), 
      clinical target volume (CTV), planning treatment volume (PTV) and organs at risk 
      (OAR) were contoured. Displacements of the bladder wall were determined at all 
      directions. Cumulative DVHs were generated for the volumes of interest. Using the 
      same beam arrangements for both the EB and FB CT series, DVHs were also produced. 
      RESULTS: The mean bladder volume was 119.3+/-55.9 cm3 and 264.3+/-145.7 cm3 for EB 
      and FB CT series, respectively (p<0.001). The maximum bladder wall displacement 
      was observed at cranial direction (2.2+/-0.6 cm for the EB vs. 3.4+/-1.0 cm for the 
      FB series; p<0.001) and at caudal direction (2.3+/-0.6 cm for the EB vs. 3.6+/-1.0 cm 
      for the FB series; p<0.001). Standard anisotropic margins of 2 cm in craniocaudal 
      and posterior-anterior directions and 1.2 cm in lateral direction gave coverage 
      to 75% of all bladder movements caused by FB. Analysis of DVHs and tumor control 
      probability (TCP) calculations gave same results (74%), while normal tissue 
      complication probability (NTCP) of the rectum showed no significant changes. 
      CONCLUSION: CT scans series with empty and full bladder, performed at simulation 
      time, could offer a potential advantage to evaluate the target expansion 
      necessary to cover the bladder wall for each patient, giving more information 
      about safe margining.
FAU - Bozios, G
AU  - Bozios G
AD  - Department of Radiotherapy, University Hospital of Ioannina, Ioannina, Greece. 
      gbozios@gmail.com
FAU - Capizzello, A
AU  - Capizzello A
FAU - Tsekeris, P
AU  - Tsekeris P
LA  - eng
PT  - Journal Article
PL  - Cyprus
TA  - J BUON
JT  - Journal of B.U.ON. : official journal of the Balkan Union of Oncology
JID - 100883428
SB  - IM
MH  - Aged
MH  - Female
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Radiotherapy Planning, Computer-Assisted/*methods
MH  - Tomography, X-Ray Computed
MH  - Urinary Bladder Neoplasms/pathology/*radiotherapy
EDAT- 2010/10/14 06:00
MHDA- 2010/12/22 06:00
CRDT- 2010/10/14 06:00
PHST- 2010/10/14 06:00 [entrez]
PHST- 2010/10/14 06:00 [pubmed]
PHST- 2010/12/22 06:00 [medline]
PST - ppublish
SO  - J BUON. 2010 Jul-Sep;15(3):489-95.