ABSTRACT
PURPOSE: We propose a method of image-guided brachytherapy (IGBT) that combines MRI-based target volume delineation for the first fraction with CT datasets of subsequent fractions, using an automatic, applicator-based co-registration, and report our preliminary experience. MATERIALS AND METHODS: The MRI of the first fraction was used for the first brachytherapy planning. For each subsequent brachytherapy fraction, after the same applicator insertion, a new CT scan with the applicator in place was obtained. The MR image set was registered to the subsequent brachytherapy treatment planning CT using the applicator for rigid body registration. To demonstrate the registration quality, we used here the Dice index as a measurement of tandem delineation overlap between CT and MRI. RESULTS: The median Dice index was 0.879 (range 0.610-0.932), which indicated that the contours on CT and MRI fitted well. With this combination method, the median D90 of HR CTV and the calculated D2 cm3 of the bladder, rectum, and sigmoid in each fraction were 7.2 (4.0-10.4), 5.9 (2.3-7.7), 4.0 (1.9-6.7), and 3.8 (0.6-7.2) Gy, respectively. CONCLUSION: Our described method of MRI-guided IGBT offers a practical option for the benefits of target delineation.
Subject(s)
Brachytherapy/methods , Magnetic Resonance Imaging, Interventional/methods , Radiography, Interventional/methods , Tomography, X-Ray Computed/methods , Uterine Cervical Neoplasms/radiotherapy , Workflow , Cervix Uteri/diagnostic imaging , Female , Humans , Multimodal Imaging/methods , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted/methodsABSTRACT
BACKGROUND AND PURPOSE: To relieve the pain and distress experienced by women who undergo high-dose-rate intracavitary radiotherapy (HDR-ICRT) for cervical cancer and to improve the current status of gynecologic brachytherapy in Japan, a new intravenous anesthetic protocol involving the administration of a combination of propofol and ketamine was developed. The primary aim of this study is to investigate the efficacy and safety of this new anesthetic protocol during HDR-ICRT for cervical cancer. METHODS AND MATERIALS: All the patients who were diagnosed with cervical cancer between December 2008 and February 2011, treated with three-channel brachytherapy and subjected to the new sedation protocol, were evaluated. A visual analog scale (VAS) was used to assess the pain during brachytherapy, and we collected VAS score at the next HDR-ICRT. Toxicities were graded using the Common Toxicity Criteria, version 3. RESULTS: A total of 178 sessions of HDR-ICRT were delivered to 57 patients. The patients' median VAS pain score was 0 (range, 0-10). The most frequent side effect was Grade 1-2 nausea, which occurred in 33 sessions (34%). However, 13 of 14 patients received concurrent cisplatin chemotherapy. None of the patients experienced Grade 3 or 4 adverse events. CONCLUSIONS: We have demonstrated that our new intravenous anesthetic protocol produces appropriate effects and can be performed by radiation oncologists who were required to finish training in basic life support and the cooperative system of emergency according to in-house guideline.
Subject(s)
Anesthesia, Intravenous , Anesthetics, Intravenous , Brachytherapy/adverse effects , Carcinoma/radiotherapy , Pain/prevention & control , Uterine Cervical Neoplasms/radiotherapy , Adult , Aged , Aged, 80 and over , Anesthesia, Intravenous/adverse effects , Antineoplastic Agents/therapeutic use , Carcinoma/drug therapy , Chemoradiotherapy/adverse effects , Cisplatin/therapeutic use , Female , Humans , Japan , Ketamine , Middle Aged , Pain/etiology , Pain Measurement , Propofol , Uterine Cervical Neoplasms/drug therapyABSTRACT
To evaluate the intra- and interfractional gastric motion using repeated CT scans, six consecutive patients with gastric lymphoma treated at our institution between 2006 and 2008 were included in this study. We performed a simulation and delivered RT before lunch after an overnight fast to minimize the stomach volume. These patients underwent repeated CT scanning at mild inhale and exhale before their course of treatment. The repeated CT scans were matched on bony anatomy to the planning scan. The center of stomach was determined in the X (lateral), Y (superior-inferior), and Z (ventro-dorsal) coordinate system to evaluate the intra- and interfractional motion of the stomach on each CT scan. We then calculated the treatment margins. Each patient was evaluated four to five times before their course of RT. The average intrafractional motions were -12.1, 2.4 and 4.6 mm for the superior-inferior (SI), lateral (LAT), and ventro-dorsal (VD) direction. The average interfractional motions of the center of the stomach were -4.1, 1.9 and 1.5 mm for the SI, LAT and VD direction. The average of the vector length was 13.0 mm. The systematic and random errors in SI direction were 5.1, and 4.6 mm, respectively. The corresponding figures in LAT and VD directions were 10.9, 5.4, 10.0, and 6.5 mm, respectively. Thus, the 15.9, 31.0 and 29.6 mm of margins are required for the SI, LAT, and VD directions, respectively. We have demonstrated not only intrafractional stomach motion, but also interfractional motion is considerable.
