1.A novel method for determining dose distribution on panoramic reconstruction computed tomography images from radiotherapy computed tomography
Hiroyuki OKAMOTO ; Madoka SAKURAMACHI ; Wakako YATSUOKA ; Takao UENO ; Kouji KATSURA ; Naoya MURAKAMI ; Satoshi NAKAMURA ; Kotaro IIJIMA ; Takahito CHIBA ; Hiroki NAKAYAMA ; Yasunori SHUTO ; Yuki TAKANO ; Yuta KOBAYASHI ; Hironori KISHIDA ; Yuka URAGO ; Masato NISHITANI ; Shuka NISHINA ; Koushin ARAI ; Hiroshi IGAKI
Imaging Science in Dentistry 2024;54(2):129-137
Purpose:
Patients with head and neck cancer (HNC) who undergo dental procedures during radiotherapy (RT) face an increased risk of developing osteoradionecrosis (ORN). Accordingly, new tools must be developed to extract critical information regarding the dose delivered to the teeth and mandible. This article proposes a novel approach for visualizing 3-dimensional planned dose distributions on panoramic reconstruction computed tomography (pCT) images.
Materials and Methods:
Four patients with HNC who underwent volumetric modulated arc therapy were included. One patient experienced ORN and required the extraction of teeth after RT. In the study approach, the dental arch curve (DAC) was defined using an open-source platform. Subsequently, pCT images and dose distributions were generated based on the new coordinate system. All teeth and mandibles were delineated on both the original CT and pCT images. To evaluate the consistency of dose metrics, the Mann-Whitney U test and Student t-test were employed.
Results:
A total of 61 teeth and 4 mandibles were evaluated. The correlation coefficient between the 2 methods was 0.999, and no statistically significant difference was observed (P>0.05). This method facilitated a straightforward and intuitive understanding of the delivered dose. In 1 patient, ORN corresponded to the region of the root and the gum receiving a high dosage (approximately 70 Gy).
Conclusion
The proposed method particularly benefits dentists involved in the management of patients with HNC. It enables the visualization of a 3-dimensional dose distribution in the teeth and mandible on pCT, enhancing the understanding of the dose delivered during RT.
2.Phase I/II prospective clinical trial for the hybrid of intracavitary and interstitial brachytherapy for locally advanced uterine cervical cancer
Naoya MURAKAMI ; Miho WATANABE ; Takashi UNO ; Shuhei SEKII ; Kayoko TSUJINO ; Takahiro KASAMATSU ; Yumiko MACHITORI ; Tomomi AOSHIKA ; Shingo KATO ; Hisako HIROWATARI ; Yuko KANEYASU ; Tomio NAKAGAWA ; Hitoshi IKUSHIMA ; Ken ANDO ; Masumi MURATA ; Ken YOSHIDA ; Hiroto YOSHIOKA ; Kazutoshi MURATA ; Tatsuya OHNO ; Noriyuki OKONOGI ; Anneyuko I. SAITO ; Mayumi ICHIKAWA ; Takahito OKUDA ; Keisuke TSUCHIDA ; Hideyuki SAKURAI ; Ryoichi YOSHIMURA ; Yasuo YOSHIOKA ; Atsunori YOROZU ; Naonobu KUNITAKE ; Hiroyuki OKAMOTO ; Koji INABA ; Tomoyasu KATO ; Hiroshi IGAKI ; Jun ITAMI
Journal of Gynecologic Oncology 2023;34(3):e24-
Objective:
The purposes of this trial were to demonstrate the feasibility and effectiveness of the hybrid of intracavitary and interstitial brachytherapy (HBT) for locally advanced cervical cancer patients in the phase I/II prospective clinical trial.
Methods:
Patients with FIGO stage IB2-IVA uterine cervical cancer pretreatment width of which was ≥5 cm measured by magnetic resonance imaging were eligible for this clinical trial. The protocol therapy included 30–30.6 Gy in 15–17 fractions of whole pelvic radiotherapy concurrent with weekly CDDP, followed by 24 Gy in 4 fractions of HBT and pelvic radiotherapy with a central shield up to 50–50.4 Gy in 25–28 fractions. The primary endpoint of phase II part was 2-year pelvic progression-free survival (PPFS) rate higher than historical control of 64%.
Results:
Between October 2015 and October 2019, 73 patients were enrolled in the initial registration and 52 patients proceeded to the secondary registration. With the median follow-up period of 37.3 months (range, 13.9–52.9 months), the 2- PPFS was 80.7% (90% confidence interval [CI]=69.7%–88%). Because the lower range of 90% CI of 2-year PPFS was 69.7%, which was higher than the historical control ICBT data of 64%, therefore, the primary endpoint of this study was met.
Conclusion
The effectiveness of HBT were demonstrated by a prospective clinical study. Because the dose goal determined in the protocol was lower than 85 Gy, there is room in improvement for local control. A higher dose might have been needed for tumors with poor responses.