PMID- 12242130
OWN - NLM
STAT- MEDLINE
DCOM- 20030306
LR  - 20190901
IS  - 0167-8140 (Print)
IS  - 0167-8140 (Linking)
VI  - 64
IP  - 2
DP  - 2002 Aug
TI  - The dose to the parotid glands with IMRT for oropharyngeal tumors: the effect of 
      reduction of positioning margins.
PG  - 197-204
AB  - PURPOSE: The aim of this paper is to quantify the importance of the reduction of 
      positioning margins applied to the clinical target volume (CTV) on the dose 
      distribution of the parotid gland for different intensity-modulated radiotherapy 
      (IMRT) strategies for the treatment of oropharyngeal cancer. METHODS AND 
      MATERIALS: CTVs and organs at risk were delineated in the planning computed 
      tomographic (CT) scans of three patients. Margins of 0, 3, 6 and 9mm were applied 
      to the CTVs in order to obtain the planning target volumes (PTVs). Three IMRT 
      strategies were used to optimize the dose distribution. RESULTS: The analysis of 
      the three IMRT strategies resulted in: (1) an optimal dose distribution in the 
      PTV; (2) optimal dose distribution in the PTV while sparing the parotid gland and 
      (3) more parotid gland sparing but at expense of the dose homogeneity in the PTV. 
      The mean parotid dose increased linearly with increasing margin by approximately 
      1.3Gy per mm. As a result, the normal complication probability (NTCP) for 
      xerostomia decreased when smaller margins were applied. Reducing the margin from 
      6 to 3mm resulted in an NTCP reduction of approximately 20%. CONCLUSION: Reducing 
      the CTV-PTV margin by improving the patient position accuracy may lead to a 
      significant reduction of NTCP for the IMRT treatment of the oropharyngeal tumors 
      and lymph nodes level II.
FAU - van Asselen, Bram
AU  - van Asselen B
AD  - Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 
      100, Utrecht, The Netherlands.
FAU - Dehnad, Homan
AU  - Dehnad H
FAU - Raaijmakers, Cornelis P J
AU  - Raaijmakers CP
FAU - Roesink, Judith M
AU  - Roesink JM
FAU - Lagendijk, Jan J W
AU  - Lagendijk JJ
FAU - Terhaard, Chris H J
AU  - Terhaard CH
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - Ireland
TA  - Radiother Oncol
JT  - Radiotherapy and oncology : journal of the European Society for Therapeutic 
      Radiology and Oncology
JID - 8407192
SB  - IM
MH  - Humans
MH  - Oropharyngeal Neoplasms/diagnostic imaging/*radiotherapy
MH  - Parotid Gland/diagnostic imaging/physiopathology/*radiation effects
MH  - Radiotherapy Dosage
MH  - Radiotherapy Planning, Computer-Assisted/methods
MH  - Radiotherapy, Conformal/*methods
MH  - Tomography, X-Ray Computed
MH  - Xerostomia/prevention & control
EDAT- 2002/09/21 10:00
MHDA- 2003/03/07 04:00
CRDT- 2002/09/21 10:00
PHST- 2002/09/21 10:00 [pubmed]
PHST- 2003/03/07 04:00 [medline]
PHST- 2002/09/21 10:00 [entrez]
AID - S0167814002001524 [pii]
AID - 10.1016/s0167-8140(02)00152-4 [doi]
PST - ppublish
SO  - Radiother Oncol. 2002 Aug;64(2):197-204. doi: 10.1016/s0167-8140(02)00152-4.