Limits...
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

Cervical vertebra delineation (C2, axis) for bony landmark based fusion.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Cervical vertebra delineation (C2, axis) for bony landmark based fusion.

Mentions: All the acquired CT images were imported into the treatment planning system (TPS, Eclipse 8.6 version; Varian Medical Systems, Palo Alto, CA, USA). According to the consensus guidelines on N0 neck delineation, all LN levels were manually contoured on all the axial images of both groups (Fig. 1). As a bony landmark for image fusion, the second cervical vertebra, axis was also manually contoured on each CT scan (Fig. 2). For minimizing inter-observer variations in our data, delineation of all LN levels in each acquired CT scan was contoured by the same physician. Moreover, after all the LN levels were delineated, two radiation oncologists at our department reviewed the neck LN level delineation.


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)

Cervical vertebra delineation (C2, axis) for bony landmark based fusion.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Cervical vertebra delineation (C2, axis) for bony landmark based fusion.
Mentions: All the acquired CT images were imported into the treatment planning system (TPS, Eclipse 8.6 version; Varian Medical Systems, Palo Alto, CA, USA). According to the consensus guidelines on N0 neck delineation, all LN levels were manually contoured on all the axial images of both groups (Fig. 1). As a bony landmark for image fusion, the second cervical vertebra, axis was also manually contoured on each CT scan (Fig. 2). For minimizing inter-observer variations in our data, delineation of all LN levels in each acquired CT scan was contoured by the same physician. Moreover, after all the LN levels were delineated, two radiation oncologists at our department reviewed the neck LN level delineation.

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