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Advances in Radiotherapy
& Nuclear Medicine 3D-PT-assisted CT-guided I RSI
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such as adenocarcinoma, adenosquamous carcinoma, and the complex anatomical structures of the head and neck
sarcoma, are less common. In the 2022 classification of region and the presence of numerous critical organs, pose
head and neck tumors by the World Health Organization, significant challenges in accurately implementing pre-
additional categories such as mesenchymal tumors, operative planning requirements. These complexities can
melanomas, hematolymphoid tumors, neuroendocrine lead to suboptimal post-operative dose verification, due to
tumors, and hereditary tumor syndromes were listed difficulties in fully achieving the planned radiation doses.
separately. 2 To address this challenge, In 2002, Professor Zhang Jianguo

Globally, the annual incidence of HNC surpasses pioneered the development of three-dimensional-printed
550,000 cases, resulting in approximately 300,000 templates (3D-PTs), significantly enhancing precision
fatalities. HNC accounts for 30% of all malignant tumors, during RSI while facilitating effective pre-operative
3
with surgical intervention being the primary therapeutic planning. 20
approach. The 5-year overall survival (OS) of patients In 2015, Professor Wang Junjie designed 3D-PTs with
diagnosed with stage Ⅰ–Ⅱ disease is typically between coordinates, fixed needle paths, and digital features. The
70% and 90%. Concurrent chemoradiotherapy with a 3D-PTs are categorized into two types: the 3D printing
1,4
cisplatin-based regimen has long been established as the non-co-planar template (3D-PNCT) and the 3D printing
standard in the definitive management of locally advanced co-planar template (3D-PCT). Tumor information is
20
or inoperable HNC. Systematic reviews have consistently transferred into the computer treatment planning system
4
demonstrated local-regional control (LRC) rates ranging after digital processing using imaging-guided technology.
from 58% to 61%, with 2-year OS rates between 67% Physicians and physicists collaborate to delineate target
and 74% and progression-free survival rates from 62% areas, define prescription doses for the tumor and critical
to 69%. Despite the multimodal treatment approach for organs, design needle paths, and print personalized
5
HNC, locoregional recurrence or development of distant templates using 3D printers. These templates assist in
metastases was reported in 50 – 60% of patients with Stage guiding RSI and achieving highly conformal irradiation
Ⅲ or Ⅳ disease. Unfortunately, most of these relapses of tumor targets. The 3D-PNCT is recommended for non-
are ineligible for surgery or re-radiotherapy, leaving co-planar seed needle insertion in complicated tumor
systemic therapy and optimal supportive care as primary locations. This technology allows for the design of needle
options. Historical data from the 20 century indicated paths from different angles, directions, and depths to
th
that the median OS of patients with metastatic HNC accommodate irregular tumor shapes, complex anatomical
following comprehensive therapy was only 6 months. locations, and the presence of numerous critical organs,
6
This poor prognosis has led to extensive research over ensuring that post-operative dose verification aligns with
the past two decades into various treatment modalities, the pre-operative planning requirements. Conversely,
including brachytherapy, chemotherapy, targeted therapy, 3D-PCT is recommended for RSI, where needle paths
immunotherapy, and more. 6-8 can be aligned parallel to the tumor. These templates are

Brachytherapy using radioactive seeds is recognized standardized to make operations more convenient.
as a standard treatment for early-stage prostate cancer. Using 3D-PT technology with CT-guided techniques
9
This technique involves the insertion of iodine-125 ( I) ensures that seed implantation in brachytherapy is a
125
seeds (measuring 4.5×0.8 mm and enclosed in a nickel- precisely planned, controllable, and assessable procedure.
titanium alloy shell) into the prostate gland with a This approach enhances the accuracy and efficacy of low-
transrectal ultrasound-guided template to effectively dose-rate brachytherapy, making it a minimally invasive
target and eradicate the tumor. One of the key benefits surgical technique with improved treatment outcomes
of his approach is its ability to deliver high local doses of (Figures 1 and 2). Several critical factors, such as the
radiation while minimizing damage to the surrounding target site, puncture trajectory, and dose distribution,
healthy tissues. The procedure is minimally invasive and can influence the efficacy and safety of seed implantation.
typically performed in a single session. In addition to its Advances in medical imaging have led to the development
application in prostate cancer, some researchers have used of sophisticated devices that enable precise localization
this technology for the treatment of malignant tumors of target sites. While these technological advancements
21
across various fields. 10-19 assist operators in making accurate needle punctures,
In 2002, Professor Wang Junjie introduced computed inexperienced practitioners may still struggle to ensure
tomography (CT)-guided techniques for radioactive seed the correct spatial distribution of the needles. Previous
implantation (RSI) in managing recurrent HNC, yielding studies have demonstrated the efficacy and safety of
exceptional outcomes in local tumor control. However, 3D-PT-assisted 125 I RSI for treating HNC. 22-25 However,

Volume 2 Issue 4 (2024) 2 doi: 10.36922/arnm.4212