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Application of Volumetric Modulated Arc Therapy and Simultaneous Integrated Boost Techniques to Prepare "Safe Margin" in the Rabbit VX2 Limb Tumor Model.

Wang CW, Zhou Y, Bai JP, Liu H, Liu Y, Shi GL, Ding JJ, Ma DH, Li WT, Xie PM, Yan Y - Med. Sci. Monit. (2015)

Bottom Line: After radiotherapy, the two groups showed a significant difference in the GTVboost area.The 3D-PDA observation showed that tumor vascular structures decreased significantly.The formation of a necrotic zone can be effectively defined as safe margin in the GTVboost area. showing potential clinical applicability.

View Article: PubMed Central - PubMed

Affiliation: Department of Bone and Soft Tissue, The Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China (mainland).

ABSTRACT

Background: In this study, we aimed to establish the rabbit VX2 limb tumor model, and then prepare a "necrotic zone" as a safe margin by volumetric modulated arc therapy and simultaneous integrated boost (VMAT-SIB) technique applied in the areas where the tumor is located adjacent to the bone (GTVboost area).

Material and methods: Rabbits in the control group (n=10) were not treated, while those in the test group (n=10) were treated with the SIB schedule delivering a dose of 40Gy, 35Gy, 30Gy, and 25Gy to the GTVboost, GTV (gross tumor volume), CTV (clinical target volume), and PTV (planning target volume) in 10 fractions. Magnetic resonance diffusion-weighted imaging (MRDWI), 3-dimensional power Doppler angiography (3D-PDA), and histological changes were observed after radiotherapy.

Results: After radiotherapy, the two groups showed a significant difference in the GTVboost area. In the test group, the tumor necrosis showed a significantly low signal in DWI and high signal in apparent diffusion coefficient (ADC) maps. The 3D-PDA observation showed that tumor vascular structures decreased significantly. Histological analysis demonstrated that a necrotic zone could be generated in the GTVboost area, and microscopic examination observed cell necrosis and fibroplasia.

Conclusions: This studies demonstrated the feasibility of using VMAT-SIB technique in the rabbit VX2 limb tumor model. The formation of a necrotic zone can be effectively defined as safe margin in the GTVboost area. showing potential clinical applicability.

No MeSH data available.


Related in: MedlinePlus

Radiotherapy process. (A) Making thermoplastic; (B) Localization using Big Bore CT simulation scan; (C) delineation of the target volumes; (D) using two full arcs, (E) center calibration after the plan has been completed; (F) position restoration before radiotherapy; (G) radiotherapy.
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f2-medscimonit-21-2397: Radiotherapy process. (A) Making thermoplastic; (B) Localization using Big Bore CT simulation scan; (C) delineation of the target volumes; (D) using two full arcs, (E) center calibration after the plan has been completed; (F) position restoration before radiotherapy; (G) radiotherapy.

Mentions: Animals were placed in a prone position on a five-point fixation mask (Posicast Thermoplastics, Civco Medical Solutions, Kalowa, IA,USA) (Figure 2A). A Big Bore CT simulation scan (Brilliance Big Bore; Philips, Best, Netherlands) was used to defined the scanning area from the pelvis to the knee and marked with lead wire (Figure 2B).The contrast agent, iopamidol (Shanghai Bracco Sine Pharmaceutical Co. Ltd., Shanghai, China), was used in the dose of 2 ml/kg. The image was delivered to Eclipse treatment planning system (version 10.0, Varian Medical Systems, USA) to make it convenient for the physician to delineate the target volume. The areas where tumor was located adjacent to the bones were defined as GTVboost (gross tumor volume boost) and given the highest dose of radiation; GTV (gross tumor volume) included all tumors. CTV (clinical target volume) was defined as a 0.3–0.5 cm expansion of GTV on X-axis and Z-axis and a 3cm expansion on Y-axis. PTV (planning target volume) was defined as a 0.3–0.5 cm expansion of CTV (Figure 2C).


Application of Volumetric Modulated Arc Therapy and Simultaneous Integrated Boost Techniques to Prepare "Safe Margin" in the Rabbit VX2 Limb Tumor Model.

Wang CW, Zhou Y, Bai JP, Liu H, Liu Y, Shi GL, Ding JJ, Ma DH, Li WT, Xie PM, Yan Y - Med. Sci. Monit. (2015)

Radiotherapy process. (A) Making thermoplastic; (B) Localization using Big Bore CT simulation scan; (C) delineation of the target volumes; (D) using two full arcs, (E) center calibration after the plan has been completed; (F) position restoration before radiotherapy; (G) radiotherapy.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4544349&req=5

f2-medscimonit-21-2397: Radiotherapy process. (A) Making thermoplastic; (B) Localization using Big Bore CT simulation scan; (C) delineation of the target volumes; (D) using two full arcs, (E) center calibration after the plan has been completed; (F) position restoration before radiotherapy; (G) radiotherapy.
Mentions: Animals were placed in a prone position on a five-point fixation mask (Posicast Thermoplastics, Civco Medical Solutions, Kalowa, IA,USA) (Figure 2A). A Big Bore CT simulation scan (Brilliance Big Bore; Philips, Best, Netherlands) was used to defined the scanning area from the pelvis to the knee and marked with lead wire (Figure 2B).The contrast agent, iopamidol (Shanghai Bracco Sine Pharmaceutical Co. Ltd., Shanghai, China), was used in the dose of 2 ml/kg. The image was delivered to Eclipse treatment planning system (version 10.0, Varian Medical Systems, USA) to make it convenient for the physician to delineate the target volume. The areas where tumor was located adjacent to the bones were defined as GTVboost (gross tumor volume boost) and given the highest dose of radiation; GTV (gross tumor volume) included all tumors. CTV (clinical target volume) was defined as a 0.3–0.5 cm expansion of GTV on X-axis and Z-axis and a 3cm expansion on Y-axis. PTV (planning target volume) was defined as a 0.3–0.5 cm expansion of CTV (Figure 2C).

Bottom Line: After radiotherapy, the two groups showed a significant difference in the GTVboost area.The 3D-PDA observation showed that tumor vascular structures decreased significantly.The formation of a necrotic zone can be effectively defined as safe margin in the GTVboost area. showing potential clinical applicability.

View Article: PubMed Central - PubMed

Affiliation: Department of Bone and Soft Tissue, The Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China (mainland).

ABSTRACT

Background: In this study, we aimed to establish the rabbit VX2 limb tumor model, and then prepare a "necrotic zone" as a safe margin by volumetric modulated arc therapy and simultaneous integrated boost (VMAT-SIB) technique applied in the areas where the tumor is located adjacent to the bone (GTVboost area).

Material and methods: Rabbits in the control group (n=10) were not treated, while those in the test group (n=10) were treated with the SIB schedule delivering a dose of 40Gy, 35Gy, 30Gy, and 25Gy to the GTVboost, GTV (gross tumor volume), CTV (clinical target volume), and PTV (planning target volume) in 10 fractions. Magnetic resonance diffusion-weighted imaging (MRDWI), 3-dimensional power Doppler angiography (3D-PDA), and histological changes were observed after radiotherapy.

Results: After radiotherapy, the two groups showed a significant difference in the GTVboost area. In the test group, the tumor necrosis showed a significantly low signal in DWI and high signal in apparent diffusion coefficient (ADC) maps. The 3D-PDA observation showed that tumor vascular structures decreased significantly. Histological analysis demonstrated that a necrotic zone could be generated in the GTVboost area, and microscopic examination observed cell necrosis and fibroplasia.

Conclusions: This studies demonstrated the feasibility of using VMAT-SIB technique in the rabbit VX2 limb tumor model. The formation of a necrotic zone can be effectively defined as safe margin in the GTVboost area. showing potential clinical applicability.

No MeSH data available.


Related in: MedlinePlus