PMID- 17869676
OWN - NLM
STAT- MEDLINE
DCOM- 20071109
LR  - 20220409
IS  - 0360-3016 (Print)
IS  - 0360-3016 (Linking)
VI  - 69
IP  - 2
DP  - 2007 Oct 1
TI  - Treatment planning for MRI assisted brachytherapy of gynecologic malignancies 
      based on total dose constraints.
PG  - 619-27
AB  - PURPOSE: To develop a method for treatment planning and optimization of magnetic 
      resonance imaging (MRI)-assisted gynecologic brachytherapy that includes 
      biologically weighted total dose constraints. METHODS AND MATERIALS: The applied 
      algorithm is based on the linear-quadratic model and includes dose, dose rate, 
      and fractionation of the whole radiotherapy setting, consisting of external beam 
      therapy plus high-dose-rate (HDR), low-dose-rate (LDR) or pulsed-dose rate (PDR) 
      brachytherapy. Biologically effective doses (BED) are converted to more familiar 
      isoeffective (equivalent) doses in 2-Gy fractions. For individual treatment 
      planning of each brachytherapy fraction, the algorithm calculates the physical 
      dose per brachytherapy fraction that corresponds to a predefined isoeffective 
      total dose constraint. Achieved target dose and sparing of organs at risk of 
      already delivered brachytherapy fractions are incorporated. RESULTS: Since 
      implementation for use in clinical routine in 2001, MRI assisted treatment plans 
      of 216 gynecologic patients (161 HDR, 55 PDR brachytherapy) were prospectively 
      optimized taking into account isoeffective dose-volume histogram-based total dose 
      constraints for high-risk clinical target volume (HR CTV) and organs at risk 
      (bladder, rectum, sigmoid). The algorithm is implemented in a spreadsheet and the 
      procedure is fast and efficient. An uncertainty analysis of the isoeffective 
      total doses based on variations of tissue parameters shows that confidence 
      intervals are larger for PDR compared with HDR brachytherapy. For common 
      treatment schedules, overall uncertainties of high-risk clinical target volume 
      and organs at risk are within 8 Gy, except for the bladder when using the PDR 
      technique. CONCLUSION: The presented method to respect total dose constraints is 
      reliable and efficient and an essential tool when aiming to increase local 
      control and minimize side effects.
FAU - Lang, Stefan
AU  - Lang S
AD  - Department of Radiotherapy, Medical University of Vienna, Vienna, Austria. 
      stefan.lang@akhwien.at
FAU - Kirisits, Christian
AU  - Kirisits C
FAU - Dimopoulos, Johannes
AU  - Dimopoulos J
FAU - Georg, Dietmar
AU  - Georg D
FAU - Potter, Richard
AU  - Potter R
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Int J Radiat Oncol Biol Phys
JT  - International journal of radiation oncology, biology, physics
JID - 7603616
SB  - IM
MH  - *Algorithms
MH  - Brachytherapy/*methods
MH  - Colon, Sigmoid/radiation effects
MH  - Confidence Intervals
MH  - Dose Fractionation, Radiation
MH  - Female
MH  - Genital Neoplasms, Female/*radiotherapy
MH  - Humans
MH  - Linear Models
MH  - Magnetic Resonance Imaging, Interventional/*methods
MH  - Radiation Injuries/prevention & control
MH  - Radiotherapy Planning, Computer-Assisted/*methods
MH  - Rectum/radiation effects
MH  - Relative Biological Effectiveness
MH  - Technology, Radiologic
MH  - Urinary Bladder/radiation effects
EDAT- 2007/09/18 09:00
MHDA- 2007/11/10 09:00
CRDT- 2007/09/18 09:00
PHST- 2006/12/22 00:00 [received]
PHST- 2007/05/21 00:00 [revised]
PHST- 2007/06/02 00:00 [accepted]
PHST- 2007/09/18 09:00 [pubmed]
PHST- 2007/11/10 09:00 [medline]
PHST- 2007/09/18 09:00 [entrez]
AID - S0360-3016(07)00983-2 [pii]
AID - 10.1016/j.ijrobp.2007.06.019 [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 2007 Oct 1;69(2):619-27. doi: 
      10.1016/j.ijrobp.2007.06.019.