PDF(Pubmed)
Abstract：
UNASSIGNED: To decrease the impact of radiotherapy to healthy tissues in the head and neck region, we propose to restrict the elective neck irradiation to elective lymph nodes at risk of containing micro metastases instead of the larger lymph node volumes. To assess whether this new concept is achievable in the clinic, we determined the number, volume changes and displacement of elective lymph nodes during the course of radiotherapy.
UNASSIGNED: MRI scans of 10 head and neck cancer (HNC) patients were acquired before radiotherapy and in week 2, 3, 4 and 5 during radiotherapy. The weekly delineations of elective lymph nodes inside the lymph node levels (Ib/II/III/IVa/V) were rigidly registered and analyzed regarding number and volume. The displacement of elective lymph nodes was determined by center of mass (COM) distances, vector-based analysis and the isotropic contour expansion of the lymph nodes of the pre-treatment scan or the scan of the previous week in order to geographically cover 95% of the lymph nodes in the scans of the other weeks.
UNASSIGNED: On average, 31 elective lymph nodes in levels Ib-V on each side of the neck were determined. This number remained constant throughout radiotherapy in most lymph node levels. The volume of the elective lymph nodes reduced significantly in all weeks, up to 50% in week 5, compared to the pre-treatment scan. The largest median COM displacements were seen in level V, for example 5.2 mm in week 5 compared to the pre-treatment scan. The displacement of elective lymph nodes was mainly in cranial direction. Geographical coverage was obtained when the lymph node volumes were expanded with 7 mm in case the pre-treatment scan was used and 6.5 mm in case the scan of the previous week was used.
UNASSIGNED: Elective lymph nodes of HNC patients remained visible on MRI and decreased in size during radiotherapy. The displacement of elective lymph nodes differ per lymph node level and were mainly directed cranially. Weekly adaptation does not seem to improve coverage of elective lymph nodes. Based on our findings we expect elective lymph node irradiation is achievable in the clinic.
UNASSIGNED: MRI scans of 10 head and neck cancer (HNC) patients were acquired before radiotherapy and in week 2, 3, 4 and 5 during radiotherapy. The weekly delineations of elective lymph nodes inside the lymph node levels (Ib/II/III/IVa/V) were rigidly registered and analyzed regarding number and volume. The displacement of elective lymph nodes was determined by center of mass (COM) distances, vector-based analysis and the isotropic contour expansion of the lymph nodes of the pre-treatment scan or the scan of the previous week in order to geographically cover 95% of the lymph nodes in the scans of the other weeks.
UNASSIGNED: On average, 31 elective lymph nodes in levels Ib-V on each side of the neck were determined. This number remained constant throughout radiotherapy in most lymph node levels. The volume of the elective lymph nodes reduced significantly in all weeks, up to 50% in week 5, compared to the pre-treatment scan. The largest median COM displacements were seen in level V, for example 5.2 mm in week 5 compared to the pre-treatment scan. The displacement of elective lymph nodes was mainly in cranial direction. Geographical coverage was obtained when the lymph node volumes were expanded with 7 mm in case the pre-treatment scan was used and 6.5 mm in case the scan of the previous week was used.
UNASSIGNED: Elective lymph nodes of HNC patients remained visible on MRI and decreased in size during radiotherapy. The displacement of elective lymph nodes differ per lymph node level and were mainly directed cranially. Weekly adaptation does not seem to improve coverage of elective lymph nodes. Based on our findings we expect elective lymph node irradiation is achievable in the clinic.
摘要：
■为了减少放疗对头颈部健康组织的影响，我们建议将选择性颈部照射限制在有微转移风险的选择性淋巴结，而不是较大的淋巴结体积。为了评估这个新概念在临床上是否可以实现，我们确定了数字，放疗过程中选择性淋巴结的体积变化和移位。
■在放疗前以及放疗期间的第2、3、4和5周获得了10例头颈部癌症（HNC）患者的MRI扫描。严格记录淋巴结水平（Ib/II/III/IVa/V）内的选择性淋巴结的每周轮廓，并分析其数量和体积。选择性淋巴结的位移由质心（COM）距离确定，基于矢量的分析和治疗前扫描或前一周扫描的淋巴结的各向同性轮廓扩张，以便在其他几周的扫描中覆盖95％的淋巴结。
■平均而言，确定了颈部两侧Ib-V水平的31个选择性淋巴结。在大多数淋巴结水平的整个放射治疗过程中，该数字保持不变。选择性淋巴结的体积在所有周显著减少，与治疗前扫描相比，第5周高达50％。最大的中位值COM位移出现在V级，例如，与治疗前扫描相比，第5周为5.2mm。选择性淋巴结移位主要在颅方向。当淋巴结体积在使用治疗前扫描的情况下以7mm扩张时,并且在使用前一周的扫描的情况下以6.5mm扩张时,获得地理覆盖。
■HNC患者的选择性淋巴结在MRI上仍然可见，并且在放疗期间大小减小。选择性淋巴结的位移在每个淋巴结水平上有所不同，主要是向颅方向。每周适应似乎并不能改善选择性淋巴结的覆盖率。根据我们的发现，我们希望在临床上可以实现选择性淋巴结照射。
■在放疗前以及放疗期间的第2、3、4和5周获得了10例头颈部癌症（HNC）患者的MRI扫描。严格记录淋巴结水平（Ib/II/III/IVa/V）内的选择性淋巴结的每周轮廓，并分析其数量和体积。选择性淋巴结的位移由质心（COM）距离确定，基于矢量的分析和治疗前扫描或前一周扫描的淋巴结的各向同性轮廓扩张，以便在其他几周的扫描中覆盖95％的淋巴结。
■平均而言，确定了颈部两侧Ib-V水平的31个选择性淋巴结。在大多数淋巴结水平的整个放射治疗过程中，该数字保持不变。选择性淋巴结的体积在所有周显著减少，与治疗前扫描相比，第5周高达50％。最大的中位值COM位移出现在V级，例如，与治疗前扫描相比，第5周为5.2mm。选择性淋巴结移位主要在颅方向。当淋巴结体积在使用治疗前扫描的情况下以7mm扩张时,并且在使用前一周的扫描的情况下以6.5mm扩张时,获得地理覆盖。
■HNC患者的选择性淋巴结在MRI上仍然可见，并且在放疗期间大小减小。选择性淋巴结的位移在每个淋巴结水平上有所不同，主要是向颅方向。每周适应似乎并不能改善选择性淋巴结的覆盖率。根据我们的发现，我们希望在临床上可以实现选择性淋巴结照射。
