A Four-Dimensional CT-Based Evaluation of Techniques for Gastric Irradiation

Journal Article · Thu Nov 01 04:00:00 EDT 2007 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2007.06.062· OSTI ID:21039599

Geld, Ylanga G. van; Senan, Suresh; Slotman, Ben J ^[1]

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1. Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands)

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 (PTV{sub allphases}) were generated. Three respiratory phases for RGRT in inspiration and expiration were identified, and corresponding PTV{sub inspiration} and PTV{sub expiration} 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 PTV{sub allphases} 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.

• OSTI ID: 21039599
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 69; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
COMPUTERIZED TOMOGRAPHY
EVALUATION
HEART
IRRADIATION
KIDNEYS
LIVER
MINIMIZATION
PATIENTS
PLANNING
RADIATION DOSES
RADIOTHERAPY
RESPIRATION
SIMULATION
STOMACH
TOLERANCE