Preclinical Assessment of Volumetric Modulated Arc Therapy for Total Marrow Irradiation

Journal Article · Wed Jun 01 00:00:00 EDT 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.11.028· OSTI ID:21491765

Fogliata, Antonella ^[1]; Cozzi, Luca; Clivio, Alessandro ^[1]; Ibatici, Adalberto; Mancosu, Pietro; Navarria, Piera ^[2]; Nicolini, Giorgia ^[1]; Santoro, Armando ^[2]; Vanetti, Eugenio ^[1]; Scorsetti, Marta ^[2]

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1. Oncology Institute of Southern Switzerland, Medical Physics Unit, Bellinzona (Switzerland)
2. Istituto Clinico Humanitas, Radiation Oncology, Milan-Rozzano (Italy)

Purpose: A preclinical investigation was undertaken to explore a treatment technique for total marrow irradiation using RapidArc, a volumetric modulated arc technique. Materials and Methods: Computed tomography datasets of 5 patients were included. Plans with eight overlapping coaxial arcs were optimized for 6-MV photon beams. Dose prescription was 12 Gy in 2 Gy per fraction, normalized so that 100% isodose covered 85% of the planning target volume (PTV). The PTV consisted of the whole skeleton (including ribs and sternum), from the top of the skull to the medium distal third of the femurs. Planning objectives for organs at risk (OARs) were constrained to a median dose <6 to 7 Gy. OARs included brain, eyes, oral cavity, parotids, thyroid, lungs, heart, kidneys, liver, spleen, stomach, abdominal cavity, bladder, rectum, and genitals. Pretreatment quality assurance consisted of portal dosimetry comparisons, scoring the delivery to calculation agreement with the gamma agreement index. Results: The median total body volume in the study was 57 liters (range, 49-81 liters), for an average diameter of 47 cm (range, 46-53 cm) and a total length ranging from 95 to 112 cm. The median PTV volume was 6.8 liters (range, 5.8-10.8 liters). The mean dose to PTV was 109% (range, 107-112%). The global mean of median dose to all OARs was 4.9 Gy (range, 4.5-5.1 Gy over the 5 patients). The individual mean of median doses per organ ranged from 2.3 Gy (oral cavity) to 7.3 Gy (bowels cavity). Preclinical quality assurance resulted in a mean gamma agreement index of 94.3 {+-} 5.1%. The delivery time measured from quality assurance runs was 13 minutes. Conclusion: Sparing of normal tissues with adequate coverage of skeletal bones was shown to be feasible with RapidArc. Pretreatment quality assurance measurements confirmed the technical agreement between expected and actually delivered dose distributions, suggesting the possibility of incorporating this technique in the treatment options for patients.

• OSTI ID: 21491765
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 80, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2010.11.028; PII: S0360-3016(10)03636-9; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
BLADDER
BRAIN
COMPUTERIZED TOMOGRAPHY
EYES
FEMUR
HEART
KIDNEYS
LIVER
LUNGS
ORAL CAVITY
QUALITY ASSURANCE
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RADIOTHERAPY
RECTUM
SKULL
SPLEEN
STOMACH
THYROID
BODY
CARDIOVASCULAR SYSTEM
CENTRAL NERVOUS SYSTEM
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
DOSES
ENDOCRINE GLANDS
FACE
GASTROINTESTINAL TRACT
GLANDS
HEAD
INTESTINES
LARGE INTESTINE
MEDICINE
NERVOUS SYSTEM
NUCLEAR MEDICINE
ORGANS
RADIOLOGY
RESPIRATORY SYSTEM
SENSE ORGANS
SKELETON
THERAPY
TOMOGRAPHY
URINARY TRACT