Page 78 - ARNM-2-4

Advances in Radiotherapy
& Nuclear Medicine Comparison of online ATP versus offline ATS plans

the practicality of extensive ATS protocols because they A B
considerably increase the treatment time per patient and
disrupt the scheduling of subsequent treatments. Extended
time on the treatment couch, without timely contour
adjustments, can result in positional shifts of the target
area and OAR, thereby necessitating recalculations of the
dose distribution. Moreover, prolonged treatment sessions
may negatively impact patient compliance. Furthermore,
the substantial resource demands and specialized training
required for ATS protocols pose significant barriers to
their widespread adoption in clinical settings.
In Peng et al., CBCT was used to design adaptive
2
and non-adaptive radiotherapy plans for patients with Figure 2. Bladder and CTV in patients who were administered radical
radiotherapy (A) and post-operative radiotherapy (B). The green arrow
cervical cancer and compared the dosimetry differences indicates the change in the bladder. The blue arrow indicates the change
between workflows. They demonstrated that the CTVs of in the CTV.
the adaptive plan were superior compared with those of Abbreviation: CTV: Clinical target volume.
the virtual non-adaptive plan in terms of the target area
dose distribution. The adaptive plan, which included the Determining the applicable range of volume changes
rectum, bladder, and small bowel, was superior compared in CTV and whether an increase in the OAR volume
with the virtual non-adaptive plan. In our post-operative poses specific risks and complications is necessary. This
radiotherapy group, the ATS workflow increased the requires further exploration and verification. Furthermore,
dose received by the clinical target area by approximately determining whether patients require rescanning and
0.7% for the CTV-Dmean and 0.6% for the PTV-Dmean. readaptive radiotherapy due to prolonged positioning
Furthermore, it reduced the dose to the corresponding on the examination bed during each session is necessary.
OAR. Our finding is similar to the results of the study of Peng Consequently, future studies are required to ascertain
et al. However, in the radical radiotherapy group, the ATS the applicability of ATS and ATP, refine automatic dose
workflow increased the dose administered to the clinical optimization algorithms, and enhance the automatic
target area more effectively than the ATP plan did, with contouring process. Parchur et al. used machine learning
an increase of approximately 0.5% and 0.6% for the CTV techniques that used features such as structural similarity
D and PTV D , respectively. However, the ATS workflow and changes in local entropy to automatically assess whether
95
95
also increased the dose administered to the corresponding specific routine MRI datasets require online adaptive
30
OAR. Our finding contradicts the results of the study of replanning. Although automated, rapid determination of
the need for online adaptive replanning does not completely
Peng et al. which may be attributable to the fact that the resolve all planning issues. However, it can contribute
target location changed as the bladder filled up. Herein, to reducing unnecessary manual labor and save time for
patients who were administered radical radiotherapy patients and the treatment machine. Therefore, our future
exhibited a significant shift in the target location as the study will focus on advancing automated dose optimization
bladder filled up when compared with patients who were algorithms and enhancing workflow efficiency.
administered post-operative radiotherapy (Figure 2). This
indicates that patients undergoing radical radiotherapy 5. Conclusion
are candidates for the ATP workflow. However, the
ATS workflow is more suitable for patients undergoing The use of online adaptive radiotherapy determined
post-operative radiotherapy. This is consistent with the by an ATS workflow for patients with cervical cancer
dosimetry conclusions of our study. considerably improves the dose distribution. When
using the ATS workflow, the corresponding OAR needs
However, due to the limited number of patients in our to be protected during radiotherapy. In addition, the
study, the smaller number of fractions analyzed, and the image quality, CTV contouring, and dose optimization
shorter clinical follow-up periods, and, it is not yet possible algorithms should be further optimized to enhance the
to confirm that the significant benefits to patient survival application of online adaptive radiotherapy in patients with
and prognosis. Furthermore, this study was conducted at a cervical cancer. Moreover, ATS and ATP exhibit their own
single center. Therefore, incorporating data from multiple dosimetric advantages in cervical cancer radiotherapy, and
centers in future studies are required to improve the their use should be individualized in different patients.
comprehensiveness and generalizability of the results. Thus, online adaptive radiotherapy for cervical cancer is

Volume 2 Issue 4 (2024) 7 doi: 10.36922/arnm.4919