PMID- 19111362
OWN - NLM
STAT- MEDLINE
DCOM- 20090915
LR  - 20181201
IS  - 1879-0887 (Electronic)
IS  - 0167-8140 (Linking)
VI  - 91
IP  - 3
DP  - 2009 Jun
TI  - Dosimetric comparison of stereotactic body radiotherapy using 4D CT and 
      multiphase CT images for treatment planning of lung cancer: evaluation of the 
      impact on daily dose coverage.
PG  - 314-24
LID - 10.1016/j.radonc.2008.11.018 [doi]
AB  - PURPOSE: To investigate the dosimetric impact of using 4D CT and multiphase 
      (helical) CT images for treatment planning target definition and the daily target 
      coverage in hypofractionated stereotactic body radiotherapy (SBRT) of lung 
      cancer. MATERIALS AND METHODS: For 10 consecutive patients treated with SBRT, a 
      set of 4D CT images and three sets of multiphase helical CT scans, taken during 
      free-breathing, end-inspiration and end-expiration breath-hold, were obtained. 
      Three separate planning target volumes (PTVs) were created from these image sets. 
      A PTV(4D) was created from the maximum intensity projection (MIP) reconstructed 
      4D images by adding a 3mm margin to the internal target volume (ITV). A PTV(3CT) 
      was created by generating ITV from gross target volumes (GTVs) contoured from the 
      three multiphase images. Finally, a third conventional PTV (denoted PTV(conv)) 
      was created by adding 5mm in the axial direction and 10mm in the longitudinal 
      direction to the GTV (in this work, GTV=CTV=clinical target volume) generated 
      from free-breathing helical CT scans. Treatment planning was performed based on 
      PTV(4D) (denoted as Plan-1), and the plan was adopted for PTV(3CT) and PTV(conv) 
      to form Plan-2 and Plan-3, respectively, by superimposing "Plan-1" onto the 
      helical free-breathing CT data set using modified beam apertures that conformed 
      to either PTV(3CT) or PTV(conv). We first studied the impact of PTV design on 
      treatment planning by evaluating the dosimetry of the three PTVs under the three 
      plans, respectively. Then we examined the effect of the PTV designs on the daily 
      target coverage by utilizing pre-treatment localization CT (CT-on-rails) images 
      for daily GTV contouring and dose recalculation. The changes in the dose 
      parameters of D(95) and D(99) (the dose received by 95% and 99% of the target 
      volume, respectively), and the V(p) (the volume receiving the prescription dose) 
      of the daily GTVs were compared under the three plans before and after setup 
      error correction. RESULTS: For all 10 patients, we found that the PTV(4D) 
      consistently resulted in the smallest volumes compared with the other PTV's 
      (p=0.005). In general, the plans generated based PTV(3CT) could provide 
      reasonably good coverage for PTV(4D), while the reverse can only achieve 90% of 
      the planned values for PTV(3CT). The coverage of both PTV(4D) and PTV(3CT) in 
      Plan-3 generally reserves the original planned values in terms of D(95), D(99), 
      and V(p,) with the average ratios of 0.996, 0.977, and 0.977, respectively, for 
      PTV(3CT), and 1.025, 1.025, and 1.0, respectively, for PTV(4D). However, it 
      increased the dose significantly to normal lung tissue. Additionally, the plans 
      generated using the PTV(4D) presented an equivalent daily target coverage 
      compared to the plans generated using the PTV(3CT) (p=0.953) and PTV(conv) 
      (p=0.773) after setup error correction. Consequently, this minimized the dose to 
      the surrounding normal lung. CONCLUSION: Compared to the conventional approach 
      using helical images for target definition, 4D CT and multiphase 3D CT have the 
      advantage to provide patient-specific tumor motion information, based on which 
      such designed PTVs could ensure daily target coverage. 4D CT-based treatment 
      planning further reduces the amount of normal lung being irradiated while still 
      providing a good target coverage when image guidance is used.
FAU - Wang, Lu
AU  - Wang L
AD  - Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 
      19111, USA. lu.wang@fccc.edu
FAU - Hayes, Shelly
AU  - Hayes S
FAU - Paskalev, Kamen
AU  - Paskalev K
FAU - Jin, Lihui
AU  - Jin L
FAU - Buyyounouski, Mark K
AU  - Buyyounouski MK
FAU - Ma, Charlie C-M
AU  - Ma CC
FAU - Feigenberg, Steve
AU  - Feigenberg S
LA  - eng
PT  - Clinical Trial, Phase I
PT  - Comparative Study
PT  - Journal Article
DEP - 20081226
PL  - Ireland
TA  - Radiother Oncol
JT  - Radiotherapy and oncology : journal of the European Society for Therapeutic 
      Radiology and Oncology
JID - 8407192
SB  - IM
MH  - Carcinoma, Non-Small-Cell Lung/*diagnostic imaging/pathology/*surgery
MH  - Dose Fractionation, Radiation
MH  - Female
MH  - Humans
MH  - Imaging, Three-Dimensional
MH  - Male
MH  - Radiographic Image Interpretation, Computer-Assisted
MH  - Radiosurgery/*methods
MH  - Radiotherapy Dosage
MH  - *Radiotherapy Planning, Computer-Assisted
MH  - Respiratory-Gated Imaging Techniques
MH  - Tomography, Spiral Computed/*methods
MH  - Treatment Outcome
EDAT- 2008/12/30 09:00
MHDA- 2009/09/16 06:00
CRDT- 2008/12/30 09:00
PHST- 2008/06/10 00:00 [received]
PHST- 2008/11/12 00:00 [revised]
PHST- 2008/11/16 00:00 [accepted]
PHST- 2008/12/30 09:00 [entrez]
PHST- 2008/12/30 09:00 [pubmed]
PHST- 2009/09/16 06:00 [medline]
AID - S0167-8140(08)00654-3 [pii]
AID - 10.1016/j.radonc.2008.11.018 [doi]
PST - ppublish
SO  - Radiother Oncol. 2009 Jun;91(3):314-24. doi: 10.1016/j.radonc.2008.11.018. Epub 
      2008 Dec 26.