Comparison of Respiratory-Gated and Respiratory-Ungated Planning in Scattered Carbon Ion Beam Treatment of the Pancreas Using Four-Dimensional Computed Tomography

Journal Article · Fri Jan 15 00:00:00 EST 2010 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2009.05.026· OSTI ID:21367618

Mori, Shinichiro ^[1]; Yanagi, Takeshi; Hara, Ryusuke ^[1]; Sharp, Gregory C ^[2]; Asakura, Hiroshi ^[3]; Kumagai, Motoki; Kishimoto, Riwa; Yamada, Shigeru; Kato, Hirotoshi; Kandatsu, Susumu; Kamada, Tadashi ^[1]

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1. Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan)
2. Department of Radiation Oncology, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts (United States)
3. Accelerator Engineering Corporation, Chiba (Japan)

Purpose: We compared respiratory-gated and respiratory-ungated treatment strategies using four-dimensional (4D) scattered carbon ion beam distribution in pancreatic 4D computed tomography (CT) datasets. Methods and Materials: Seven inpatients with pancreatic tumors underwent 4DCT scanning under free-breathing conditions using a rapidly rotating cone-beam CT, which was integrated with a 256-slice detector, in cine mode. Two types of bolus for gated and ungated treatment were designed to cover the planning target volume (PTV) using 4DCT datasets in a 30% duty cycle around exhalation and a single respiratory cycle, respectively. Carbon ion beam distribution for each strategy was calculated as a function of respiratory phase by applying the compensating bolus to 4DCT at the respective phases. Smearing was not applied to the bolus, but consideration was given to drill diameter. The accumulated dose distributions were calculated by applying deformable registration and calculating the dose-volume histogram. Results: Doses to normal tissues in gated treatment were minimized mainly on the inferior aspect, which thereby minimized excessive doses to normal tissues. Over 95% of the dose, however, was delivered to the clinical target volume at all phases for both treatment strategies. Maximum doses to the duodenum and pancreas averaged across all patients were 43.1/43.1 GyE (ungated/gated) and 43.2/43.2 GyE (ungated/gated), respectively. Conclusions: Although gated treatment minimized excessive dosing to normal tissue, the difference between treatment strategies was small. Respiratory gating may not always be required in pancreatic treatment as long as dose distribution is assessed. Any application of our results to clinical use should be undertaken only after discussion with oncologists, particularly with regard to radiotherapy combined with chemotherapy.

• OSTI ID: 21367618
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 76, Issue 1; Other Information: DOI: 10.1016/j.ijrobp.2009.05.026; PII: S0360-3016(09)00789-5; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CARBON IONS
COMPUTERIZED TOMOGRAPHY
FOUR-DIMENSIONAL CALCULATIONS
ION BEAMS
NEOPLASMS
PANCREAS
PLANNING
RADIATION DOSE DISTRIBUTIONS
RADIOTHERAPY
RESPIRATION
SMALL INTESTINE
BEAMS
BODY
CHARGED PARTICLES
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
DISEASES
ENDOCRINE GLANDS
GASTROINTESTINAL TRACT
GLANDS
INTESTINES
IONS
MEDICINE
NUCLEAR MEDICINE
ORGANS
RADIOLOGY
THERAPY
TOMOGRAPHY