Page 47 - ARNM-2-3

Advances in Radiotherapy
& Nuclear Medicine Image-guided interventional radiotherapy

seed permanent implantation. This research aimed to The Gamma Knife employs multiple Co-60 radiation
significantly enhance the field and connotation of RT. sources combined with rotational and focuses the
radiation to the target for eliminating tumor cells. On
9,10
2. CT-sim guided puncture biopsy the other hand, the CyberKnife utilizes a robotic system
Traditional tumor diagnosis primarily relies on to deliver radiation from various angles and directions in
bronchoscopy, gastroscopy, cholangioscopy, or CT-guided 3D space while employing real-time tracking facilitated by
percutaneous biopsy. However, the application of these interactive X-ray identification of gold markers implanted
methods presents implementation and efficacy challenges, in the tumor. Accurate identification of these markers is
including low success rate, limited positivity rate, long- crucial for successful treatment due to factors, such as
term learning curve, and operational complexity. The variability in gold marker positions due to respiratory
1-4
CT-guided percutaneous biopsy is currently performed motion, interference from bone structures, or the number
using diagnostic CT with small apertures and concave of fiducial markers during real-time tracking irradiation
beds, which lack patient stabilization positioning procedures. 11-15
systems. This deficiency makes patient positioning setup Traditionally, fiducial mark implantation has been
challenging. Moreover, the variability in individual performed using ultrasound or CT guidance. However,
physician practices significantly affects the accuracy of studies indicated that ultrasound-guided gold markers
CT-guided percutaneous, making it difficult to establish implant deviates significantly from preoperative plans,
standardized protocols. 5 leading to challenges in real-time tracking of fiducial
To overcome these challenges, a percutaneous biopsy marks and potentially impacting outcomes. 13,16 The
fixation and navigation system was designed to integrate 3D-PCT technique was developed for precise placement of
with the CT-sim. In addition, 3D-printing coplanar fiducial markers implantation based on preoperative plan.
templates (3D-PCT) were developed to enhance puncture Two key principles were proposed for successful fiducial
needle position precision, achieving accuracy within mark implantation: Two puncture needles spaced 2 cm
1 mm, emerging to be particularly beneficial for targeting apart, and the insertion of two fiducial marks per needle
small pulmonary nodules with diameters <10 mm. This while maintaining a 2 cm distance between gold markers.
6-8
integration of the CT-sim positioning facility, percutaneous Notably, fiducial markers should be optimally implanted
biopsy navigation system, and 3D-PCT enhances in the tumor or its periphery at a depth ranging from 2 to
standardized and uniform puncture biopsy, promoting 3 cm.
widespread adoption and dissemination. The procedure The procedures involved include (i) pre-operative
encompasses the following 8 steps: (i) patient positioning preparation; (ii) CT-sim scan to determine the needles
setup and CT-sim scan; (ii) marking the puncture needles entry point; (iii) standard sterilization; (iv) installing
insertion site on the patient’s skin; (iii) standard sterilization fixation stabilization navigator system and 3D-PCT;
and draping procedures; (iv) installing navigation (v) insertion of needles at the pre-planned points;
system and 3D-PCT; (v) subcutaneously inserting the (vi) implantation of the fiducial markers; (vii) CT-sim scan
puncture biopsy needle; (vi) conducting tissue sampling; to assess potential complications, such as pneumothorax
(vii) CT-sim scan to confirm the occurrence of bleeding or bleeding diligently; (viii) transferring patients back to
or pneumothorax; (viii) transferring patients back toward the ward (Figures 3 and 4).
(Figures 1 and 2).
4. CT-sim guided high-dose-rate after-
3. CT-sim guided fiducial mark implantation loading brachytherapy

RT can be categorized into two primary types: External Internal irradiation therapy comprises two main
beam RT (EBRT) and internal RT. EBRT can be further modalities: High-dose-rate brachytherapy (HDR-BT)
divided into conventional RT and stereotactic body RT and low-dose-rate interstitial brachytherapy (LDR-IBT),
(SBRT). EBRT involves delivering a dose of 180 – 200 cGy such as radioactive seed implantation. These methods
per fraction, five fractionations a week, for 4 – 6 weeks. involve the insertion of an applicator or radioactive seeds
In contrast, SBRT entails administering doses exceeding adjacent to or into carcinoma by interventional modality.
5 Gy per fraction, typically given as 3 – 5 fractions. HDR-BT is predominantly employed for the treatment of
Stereotactic radiosurgery, which is mainly employed in tumors in hollow organs, such as cervical and endometrial
the treatment of neurological tumors, requires only one cancers, as well as solid tumors, including prostate, breast,
or two fractions. The Gamma Knife and CyberKnife are and skin tumors. 17-26 LDR-IBT is primarily utilized in the
examples of SBRT equipment utilized in clinical practice. treatment of early-stage prostate cancer, as well as in cases

Volume 2 Issue 3 (2024) 2 doi: 10.36922/arnm.3781