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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

Histological changes after radiotherapy at GTVboost area. In the control group, (A) a: tumor invasion of striated muscles, b: tumor tissues. (B) a: healthy muscle tissue, b: tumor invasion of striated muscles, c: tumor cells (×100). In the test group, (C) a: necrotic zone, b: tumor parenchyma necrosis, (D) n: large areas of necrosis, unclear cells boundaries with the surrounding tissues, f: fibroplasia (×100).
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f6-medscimonit-21-2397: Histological changes after radiotherapy at GTVboost area. In the control group, (A) a: tumor invasion of striated muscles, b: tumor tissues. (B) a: healthy muscle tissue, b: tumor invasion of striated muscles, c: tumor cells (×100). In the test group, (C) a: necrotic zone, b: tumor parenchyma necrosis, (D) n: large areas of necrosis, unclear cells boundaries with the surrounding tissues, f: fibroplasia (×100).

Mentions: Gross examination revealed the tumor parenchyma in the control group showing liquefaction necrosis, and fish meat-like tumor tissues were observed in GTVboost area (Figure 6A). Observation of HE-staining under a 100× microscope showed that the tumor invasion of the striated muscles and normal structure of cells was damaged, and cell boundaries with surrounding tissues were unclear. In addition, tumor cells showed different sizes with increased cell density, enlarged and intensely stained nuclei, and some cells showed pathological mitosis (Figure 6B). In the test group, Gross examination showed that when the tumor specimens were cut transversely, GTVboost area has a necrotic zone formation (Figure 6C). The tumor parenchyma showed a great deal of fluid and tofukasu-like tissue spilled. Observation of HE-staining under a 100× microscope showed large areas of necrosis, unclear cell boundaries with the surrounding tissues, acute and chronic inflammatory cell infiltration, as well as fibroplasia in the necrotic zone (Figure 6D).


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)

Histological changes after radiotherapy at GTVboost area. In the control group, (A) a: tumor invasion of striated muscles, b: tumor tissues. (B) a: healthy muscle tissue, b: tumor invasion of striated muscles, c: tumor cells (×100). In the test group, (C) a: necrotic zone, b: tumor parenchyma necrosis, (D) n: large areas of necrosis, unclear cells boundaries with the surrounding tissues, f: fibroplasia (×100).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4544349&req=5

f6-medscimonit-21-2397: Histological changes after radiotherapy at GTVboost area. In the control group, (A) a: tumor invasion of striated muscles, b: tumor tissues. (B) a: healthy muscle tissue, b: tumor invasion of striated muscles, c: tumor cells (×100). In the test group, (C) a: necrotic zone, b: tumor parenchyma necrosis, (D) n: large areas of necrosis, unclear cells boundaries with the surrounding tissues, f: fibroplasia (×100).
Mentions: Gross examination revealed the tumor parenchyma in the control group showing liquefaction necrosis, and fish meat-like tumor tissues were observed in GTVboost area (Figure 6A). Observation of HE-staining under a 100× microscope showed that the tumor invasion of the striated muscles and normal structure of cells was damaged, and cell boundaries with surrounding tissues were unclear. In addition, tumor cells showed different sizes with increased cell density, enlarged and intensely stained nuclei, and some cells showed pathological mitosis (Figure 6B). In the test group, Gross examination showed that when the tumor specimens were cut transversely, GTVboost area has a necrotic zone formation (Figure 6C). The tumor parenchyma showed a great deal of fluid and tofukasu-like tissue spilled. Observation of HE-staining under a 100× microscope showed large areas of necrosis, unclear cell boundaries with the surrounding tissues, acute and chronic inflammatory cell infiltration, as well as fibroplasia in the necrotic zone (Figure 6D).

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