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Radial displacement of clinical target volume in node negative head and neck cancer.

Jeon W, Wu HG, Song SH, Kim JI - Radiat Oncol J (2012)

Bottom Line: We use the second cervical vertebra body as a reference point to match each CT image set.There was a statistically significant difference between the groups in terms of the mean radial displacement (p = 0.03).In addition, the mean radial displacement increased with the distance from SB.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.

ABSTRACT

Purpose: To evaluate the radial displacement of clinical target volume in the patients with node negative head and neck (H&N) cancer and to quantify the relative positional changes compared to that of normal healthy volunteers.

Materials and methods: Three node-negative H&N cancer patients and five healthy volunteers were enrolled in this study. For setup accuracy, neck thermoplastic masks and laser alignment were used in each of the acquired computed tomography (CT) images. Both groups had total three sequential CT images in every two weeks. The lymph node (LN) level of the neck was delineated based on the Radiation Therapy Oncology Group (RTOG) consensus guideline by one physician. We use the second cervical vertebra body as a reference point to match each CT image set. Each of the sequential CT images and delineated neck LN levels were fused with the primary image, then maximal radial displacement was measured at 1.5 cm intervals from skull base (SB) to caudal margin of LN level V, and the volume differences at each node level were quantified.

Results: The mean radial displacements were 2.26 (±1.03) mm in the control group and 3.05 (±1.97) in the H&N cancer patients. There was a statistically significant difference between the groups in terms of the mean radial displacement (p = 0.03). In addition, the mean radial displacement increased with the distance from SB. As for the mean volume differences, there was no statistical significance between the two groups.

Conclusion: This study suggests that a more generous radial margin should be applied to the lower part of the neck LN for better clinical target coverage and dose delivery.

No MeSH data available.


Related in: MedlinePlus

Manual measurement of maximal radial displacement at 1.5cm interval after bony landmark (C2, axis) based fusion.
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Figure 3: Manual measurement of maximal radial displacement at 1.5cm interval after bony landmark (C2, axis) based fusion.

Mentions: Each sequential CT images and delineated neck LN levels were fused with the primary image through TPS rigid registration algorithm, which is automatic image fusion system with certain point. Our reference point for the image fusion was the C2 vertebra. After image fusion, the radial displacement was quantified manually, where the maximum delineation discrepancy exist. The radial displacement evaluated in each 1.5-cm interval from skull base (SB) to the inferior margin of level V (Fig. 3). To eliminate intra and inter observer error in the manual measurement of the radial displacement, it was also reviewed by two radiation oncologists. The mean radial displacement was calculated that dividing the sum of maximal displacements between the primary and serial CT scans at each interval by two (total number of CT image acquisition - 1). The group mean radial displacement was calculated that dividing the sum of mean displacements in the same group by the total number of each group. To quantify the volume of each LN level from the registered axial images, TPS volume interpolation algorithm, which is automatic volume calculation system for delineated image was used in each registered CT images. From the primary and serial CT images in each group, the mean volume differences were calculated that dividing the sum of the volume differences at each LN level by two (total number of CT image acquisition - 1). The group mean volume difference was calculated that dividing the sum of mean volume differences in each group by the total number of each group.


Radial displacement of clinical target volume in node negative head and neck cancer.

Jeon W, Wu HG, Song SH, Kim JI - Radiat Oncol J (2012)

Manual measurement of maximal radial displacement at 1.5cm interval after bony landmark (C2, axis) based fusion.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3475961&req=5

Figure 3: Manual measurement of maximal radial displacement at 1.5cm interval after bony landmark (C2, axis) based fusion.
Mentions: Each sequential CT images and delineated neck LN levels were fused with the primary image through TPS rigid registration algorithm, which is automatic image fusion system with certain point. Our reference point for the image fusion was the C2 vertebra. After image fusion, the radial displacement was quantified manually, where the maximum delineation discrepancy exist. The radial displacement evaluated in each 1.5-cm interval from skull base (SB) to the inferior margin of level V (Fig. 3). To eliminate intra and inter observer error in the manual measurement of the radial displacement, it was also reviewed by two radiation oncologists. The mean radial displacement was calculated that dividing the sum of maximal displacements between the primary and serial CT scans at each interval by two (total number of CT image acquisition - 1). The group mean radial displacement was calculated that dividing the sum of mean displacements in the same group by the total number of each group. To quantify the volume of each LN level from the registered axial images, TPS volume interpolation algorithm, which is automatic volume calculation system for delineated image was used in each registered CT images. From the primary and serial CT images in each group, the mean volume differences were calculated that dividing the sum of the volume differences at each LN level by two (total number of CT image acquisition - 1). The group mean volume difference was calculated that dividing the sum of mean volume differences in each group by the total number of each group.

Bottom Line: We use the second cervical vertebra body as a reference point to match each CT image set.There was a statistically significant difference between the groups in terms of the mean radial displacement (p = 0.03).In addition, the mean radial displacement increased with the distance from SB.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.

ABSTRACT

Purpose: To evaluate the radial displacement of clinical target volume in the patients with node negative head and neck (H&N) cancer and to quantify the relative positional changes compared to that of normal healthy volunteers.

Materials and methods: Three node-negative H&N cancer patients and five healthy volunteers were enrolled in this study. For setup accuracy, neck thermoplastic masks and laser alignment were used in each of the acquired computed tomography (CT) images. Both groups had total three sequential CT images in every two weeks. The lymph node (LN) level of the neck was delineated based on the Radiation Therapy Oncology Group (RTOG) consensus guideline by one physician. We use the second cervical vertebra body as a reference point to match each CT image set. Each of the sequential CT images and delineated neck LN levels were fused with the primary image, then maximal radial displacement was measured at 1.5 cm intervals from skull base (SB) to caudal margin of LN level V, and the volume differences at each node level were quantified.

Results: The mean radial displacements were 2.26 (±1.03) mm in the control group and 3.05 (±1.97) in the H&N cancer patients. There was a statistically significant difference between the groups in terms of the mean radial displacement (p = 0.03). In addition, the mean radial displacement increased with the distance from SB. As for the mean volume differences, there was no statistical significance between the two groups.

Conclusion: This study suggests that a more generous radial margin should be applied to the lower part of the neck LN for better clinical target coverage and dose delivery.

No MeSH data available.


Related in: MedlinePlus