Palmgren Jan-Erik, Seppälä Jan, Jääskeläinen Ester, Anttila Maarit
Department of Radiotherapy, Kuopio University Hospital, KYS, Sädesairaala, Kuopio, Finland.
Department of Obstetrics and Gynecology, Kuopio University Hospital, KYS, Kuopio, Finland.
J Contemp Brachytherapy. 2024 Dec;16(6):443-448. doi: 10.5114/jcb.2024.146672. Epub 2024 Dec 31.
Modern applicators in cervical cancer brachytherapy (BT) have an integrated option for using interstitial needles. Even though this allows improved dose coverage in large tumors, there are cases where pre-positioned needle arrangements within applicator are not optimal. In such cases, free-hand needles (FHNs) can be inserted into tumor without using applicator's positions. However, this requires a skilled professional, because the depth of tissue must be estimated without any help of needle insertion tools, and the angle of needle is critical. Improved dose coverage of the tumor and the effect on critical organ doses are yet to be estimated, if they constitute the time used and possible additional complication risk using FHNs.
In this work, clinical brachytherapy treatment plans using FHNs were compared with hypothetical plans, in which the best possible effort was applied to produce acceptable treatment plans without FHNs. Twenty-four cervix cancer patients with FHNs were re-planned without FHNs. Biological total doses were calculated for target volumes (high-risk clinical target volume [HR-CTV], gross tumor volume [GTV], and intermediate-risk clinical target volume [IR-CTV]) and organs at risk. External beam radiation therapy (EBRT) dose distributions were summed to brachytherapy plans, and total doses were compared.
The statistically significant differences favoring FHNs usage were observed, with HR-CTV D ( = 0.043), bladder (D) ( = 0.017), rectum (D) ( = 0.022), and sigmoid (D) ( = 0.065). The average 2 Gy equivalent total doses and -values, without/with FHNs were respectively: HR-CTV D = 88.8/91.5 ( = 0.043); bladder (D) = 87.5/86.2 ( = 0.017); rectum (D) = 70.2/69.2 ( = 0.022); sigmoid (D) = 70.1/69.3 ( = 0.065) (α/β = 10 Gy for targets and α/β = 3 Gy for OARs, respectively).
The utilization of FHNs resulted in higher dose coverage to HR-CTV, and lower doses to bladder and rectum. There was no difference in GTV, bowel, or vaginal point doses.
现代宫颈癌近距离放射治疗（BT）施源器具有使用组织间插植针的集成选项。尽管这能改善大肿瘤的剂量覆盖，但在某些情况下，施源器内预先定位的针排列并非最佳。在这种情况下，可以不使用施源器的定位，徒手将针（FHNs）插入肿瘤。然而，这需要熟练的专业人员，因为必须在没有任何针插入工具帮助的情况下估计组织深度，而且针的角度很关键。如果使用FHNs会占用时间并可能带来额外的并发症风险，那么肿瘤剂量覆盖的改善以及对危及器官剂量的影响仍有待评估。
在本研究中，将使用FHNs的临床近距离放射治疗计划与假设的计划进行比较，在假设计划中，尽最大努力制定出不使用FHNs的可接受治疗计划。对24例使用FHNs的宫颈癌患者重新制定不使用FHNs的计划。计算靶区（高危临床靶区[HR-CTV]、大体肿瘤体积[GTV]和中危临床靶区[IR-CTV]）和危及器官的生物总剂量。将外照射放疗（EBRT）剂量分布与近距离放射治疗计划相加，并比较总剂量。
观察到有利于使用FHNs的统计学显著差异，HR-CTV的D（P = 0.043）、膀胱（D）（P = 0.017）、直肠（D）（P = 0.022）和乙状结肠（D）（P = 0.065）。无FHNs/有FHNs时的平均2 Gy等效总剂量和P值分别为：HR-CTV的D = 88.8/91.5（P = 0.043）；膀胱（D） = 87.5/86.2（P = 0.017）；直肠（D） = 70.2/69.2（P = 0.022）；乙状结肠（D） = 70.1/69.3（P = 0.065）（靶区的α/β = 10 Gy，危及器官的α/β = 3 Gy）。
使用FHNs可使HR-CTV的剂量覆盖更高，膀胱和直肠的剂量更低。GTV、肠道或阴道点剂量无差异。
