TY - JOUR
T1 - A Four-Dimensional CT-Based Evaluation of Techniques for Gastric Irradiation
AU - van der Geld, Ylanga G.
AU - Senan, Suresh
AU - van Sörnsen de Koste, John R.
AU - Verbakel, W. F A R
AU - Slotman, Ben J.
AU - Lagerwaard, Frank J.
PY - 2007/11/1
Y1 - 2007/11/1
N2 - Purpose: To evaluate three-dimensional conformal (3D-CRT), intensity-modulated (IMRT) and respiration-gated radiotherapy (RGRT) techniques for gastric irradiation for target coverage and minimization of renal doses. All techniques were four-dimensional (4D)-CT based, incorporating the intrafractional mobility of the target volume and organs at risk (OAR). Methods and Materials: The stomach, duodenal C-loop, and OAR (kidneys, liver, and heart) were contoured in all 10 phases of planning 4D-CT scans for five patients who underwent abdominal radiotherapy. Planning target volumes (PTVs) encompassing all positions of the stomach (PTVall phases) were generated. Three respiratory phases for RGRT in inspiration and expiration were identified, and corresponding PTVinspiration and PTVexpiration and OAR volumes were created. Landmark-based fields recommended for the Radiation Therapy Oncology Group (RTOG) 99-04 study protocol were simulated to assess PTV coverage. IMRT and 3D-CRT planning with and without additional RGRT planning were performed for all PTVs, and corresponding dose volume histograms were analyzed. Results: Use of landmark-based fields did not result in full geometric coverage of the PTVall phases in any patient. IMRT significantly reduced mean renal doses compared with 3D-CRT (15.0 Gy ± 0.9 Gy vs. 20.1 Gy ± 9.3 Gy and 16.6 Gy ± 1.5 Gy vs. 32.6 Gy ± 7.1 Gy for the left and right kidneys, respectively; p = 0.04). No significant increase in renal sparing was seen when adding RGRT to either 3D-CRT or IMRT. Tolerance doses to the other OAR were not exceeded. Conclusions: Individualized field margins are essential for gastric irradiation. IMRT plans significantly reduce renal doses, but the benefits of RGRT in gastric irradiation appear to be limited.
AB - Purpose: To evaluate three-dimensional conformal (3D-CRT), intensity-modulated (IMRT) and respiration-gated radiotherapy (RGRT) techniques for gastric irradiation for target coverage and minimization of renal doses. All techniques were four-dimensional (4D)-CT based, incorporating the intrafractional mobility of the target volume and organs at risk (OAR). Methods and Materials: The stomach, duodenal C-loop, and OAR (kidneys, liver, and heart) were contoured in all 10 phases of planning 4D-CT scans for five patients who underwent abdominal radiotherapy. Planning target volumes (PTVs) encompassing all positions of the stomach (PTVall phases) were generated. Three respiratory phases for RGRT in inspiration and expiration were identified, and corresponding PTVinspiration and PTVexpiration and OAR volumes were created. Landmark-based fields recommended for the Radiation Therapy Oncology Group (RTOG) 99-04 study protocol were simulated to assess PTV coverage. IMRT and 3D-CRT planning with and without additional RGRT planning were performed for all PTVs, and corresponding dose volume histograms were analyzed. Results: Use of landmark-based fields did not result in full geometric coverage of the PTVall phases in any patient. IMRT significantly reduced mean renal doses compared with 3D-CRT (15.0 Gy ± 0.9 Gy vs. 20.1 Gy ± 9.3 Gy and 16.6 Gy ± 1.5 Gy vs. 32.6 Gy ± 7.1 Gy for the left and right kidneys, respectively; p = 0.04). No significant increase in renal sparing was seen when adding RGRT to either 3D-CRT or IMRT. Tolerance doses to the other OAR were not exceeded. Conclusions: Individualized field margins are essential for gastric irradiation. IMRT plans significantly reduce renal doses, but the benefits of RGRT in gastric irradiation appear to be limited.
KW - 4D-CT scans
KW - Gastric
KW - IMRT
KW - Renal sparing
KW - Respiratory gating
UR - http://www.scopus.com/inward/record.url?scp=34548677048&partnerID=8YFLogxK
U2 - 10.1016/j.ijrobp.2007.06.062
DO - 10.1016/j.ijrobp.2007.06.062
M3 - Article
C2 - 17889271
AN - SCOPUS:34548677048
VL - 69
SP - 903
EP - 909
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
SN - 0360-3016
IS - 3
ER -