PMID- 17011462
OWN - NLM
STAT- MEDLINE
DCOM- 20061106
LR  - 20161124
IS  - 0360-3016 (Print)
IS  - 0360-3016 (Linking)
VI  - 66
IP  - 3
DP  - 2006 Nov 1
TI  - Online adaptive radiotherapy of the bladder: small bowel irradiated-volume 
      reduction.
PG  - 892-7
AB  - PURPOSE: To assess the potential reduction of small bowel volume receiving 
      high-dose radiation by using kilovoltage X-ray cone beam computed tomography 
      (CBCT) and quantized margin selection for adaptive bladder cancer treatment. 
      METHODS AND MATERIALS: Twenty bladder patients were planned conformally using a 
      four-field, 15-mm uniform margin technique. Two additional planning target 
      volumes (PTVs) were created using margins quantized to 5 and 10 mm in the 
      superior direction only. CBCTs (approximately 8 scans/patient) were acquired 
      during treatment. CBCT volumes were registered with CT planning scans to 
      determine setup errors and to select the appropriate PTV of the day. Margin 
      reduction in other directions was considered. Outlining of small bowel in every 
      fraction is required to properly quantify the volume of small bowel spared from 
      high doses. In the case of CBCT this is not always possible owing to artifacts 
      created by small bowel movement and the presence of gas. A simpler method was 
      adopted by considering the volume difference between PTVs created using uniform 
      and adapted margins, which corresponds to the potential volume of small bowel 
      sparing. RESULTS: The average small bowel volume that can be spared by this form 
      of adaptive radiotherapy is 31 +/- 23 cm3 (+/-1 SD). The bladder for 1 patient 
      was systematically smaller than the planning scan and hence demonstrated the 
      largest average reduction of 76 cm3. The clinical target volume to PTV margins in 
      other directions can be safely reduced to 10 mm except in the anterior direction 
      where, like the superior direction, the bladder showed significant variation. 
      CONCLUSIONS: Online CBCT-assisted plan selection based on quantized margins can 
      significantly reduce the volume of small bowel receiving high doses for some 
      bladder patients. CBCT allows the 15-mm margins used in some directions to be 
      safely reduced to 10 mm.
FAU - Burridge, Nichola
AU  - Burridge N
AD  - North Western Medical Physics, Christie Hospital NHS Trust, Manchester, UK. 
      nichola.burridge@physics.cr.man.ac.uk
FAU - Amer, Ali
AU  - Amer A
FAU - Marchant, Tom
AU  - Marchant T
FAU - Sykes, Jonathan
AU  - Sykes J
FAU - Stratford, Julie
AU  - Stratford J
FAU - Henry, Ann
AU  - Henry A
FAU - McBain, Catherine
AU  - McBain C
FAU - Price, Pat
AU  - Price P
FAU - Moore, Chris
AU  - Moore C
LA  - eng
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  - Humans
MH  - Intestine, Small/*diagnostic imaging/radiation effects
MH  - Movement
MH  - Radiation Injuries/prevention & control
MH  - Radiotherapy/methods
MH  - Radiotherapy Planning, Computer-Assisted/methods
MH  - Tomography, X-Ray Computed/*methods
MH  - Urinary Bladder/*diagnostic imaging
MH  - Urinary Bladder Neoplasms/diagnostic imaging/*radiotherapy
EDAT- 2006/10/03 09:00
MHDA- 2006/11/07 09:00
CRDT- 2006/10/03 09:00
PHST- 2006/01/06 00:00 [received]
PHST- 2006/06/29 00:00 [revised]
PHST- 2006/07/02 00:00 [accepted]
PHST- 2006/10/03 09:00 [pubmed]
PHST- 2006/11/07 09:00 [medline]
PHST- 2006/10/03 09:00 [entrez]
AID - S0360-3016(06)01168-0 [pii]
AID - 10.1016/j.ijrobp.2006.07.013 [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 2006 Nov 1;66(3):892-7. doi: 
      10.1016/j.ijrobp.2006.07.013.