Evaluation of four-dimensional computed tomography-based intensity-modulated and respiratory-gated radiotherapy techniques for pancreatic carcinoma.

Purpose: To compare conformal radiotherapy (CRT), intensity-modulated radiotherapy (IMRT), and respiration-gated radiotherapy (RGRT) planning techniques for pancreatic cancer. All target volumes were determined using four-dimensional computed tomography scans (4D CT).

Methods And Materials: The pancreatic tumor and enlarged regional lymph nodes were contoured on all 10 phases of a planning 4D CT scan for 10 patients, and the planning target volumes (PTV(all phases)) were generated.

A four-dimensional CT-based evaluation of techniques for gastric irradiation.

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.

Reproducibility of target volumes generated using uncoached 4-dimensional CT scans for peripheral lung cancer.

Background: 4-dimensional CT (4DCT) scans are increasingly used to account for mobility during radiotherapy planning. As variations in respiratory patterns can alter observed motion, with consequent changes in the generated target volumes, we evaluated the reproducibility of 4D target volumes generated during repeat uncoached quiet respiration.

Methods: A retrospective analysis was performed on two successive scans (4DCT1 and 4DCT2) generated at the same scanning session for 26 patients with peripheral lung cancer treated with stereotactic radiotherapy (SRT).

Evaluating mobility for radiotherapy planning of lung tumors: a comparison of virtual fluoroscopy and 4DCT.

Purpose: Fluoroscopy is widely used for evaluating tumor mobility in radiotherapy planning. Lung tumor mobility was scored using virtual fluoroscopy, and this was compared to mobility derived from contoured tumors in all phases of a respiration-correlated (or 4D) CT scan.

Methods And Materials: 4DCT datasets were reviewed and 29 patients were identified in whom tumors were visible on anterior-posterior fluoroscopy views.