Quantitative analysis of intra-fractional variation in CT-based image guided brachytherapy for cervical cancer patients
Brachytherapy with a remote after-loading system (RALS) plays an important role in the treatment of cervical cancer [1,2]. Recent developments in three-dimensional (3D) planning using computed tomography (CT) and magnetic resonance imaging (MRI) allow the assessment of 3D dose distributions in brachytherapy, and the widespread use of 3D-image guided brachytherapy (3D-IGBT), dose evaluation facilitates the use of dose volume histogram (DVH) in addition to the dose at “point A” approach. The Gynecologic Brachytherapy Working Group of the Groupe Européen de Curiethérapie and European Society for Radiotherapy Oncology (GEC-ESTRO) has recommended that the values of D2, D1, and D0.1 cm3 (i.e., the minimum doses to the most irradiated tissue volumes of 2 cm3, 1 cm3 and 0.1 cm3) are reported as the DVH parameters for the organ at risk (OAR) [3,4].
Abstract BACKGROUND: Early prediction of response to concurrent chemoradiotherapy (cCRT) could aid to further optimize treatment regimens for locally advanced cervical cancer (LACC) in the future. PURPOSE: To explore whether quantitative parameters from baseline (pre-therapy) magnetic resonance imaging (MRI) and FDG-PET/computed tomography (CT) have potential as predictors of early response to cCRT. MATERIAL AND METHODS: Forty-six patients with LACC undergoing cCRT after staging with FDG-PET/CT and MRI were retrospectively analyzed. Primary tumor volumes were delineated on FDG-PET/CT, T2-weighted (T2W)-M...
Conclusions: The use of asynchronous MRI for target delineation, with co-registration to CT for each fraction of brachytherapy was associated with higher D90 to the HR-CTV. We observed slightly higher D2cc rectal doses with MRI, but cumulative rectal doses were within accepted thresholds. High-risk target volumes were not consistently increased or decreased, but MRI fusion was associated with target volume changes greater than 20% in over half of the treated patients. PMID: 32695201 [PubMed]
ConclusionHybrid TRUS-CT as an imaging modality for contouring the CTVHR in IGABT for LACC is feasible and reproducible among multiple observers. TRUS-CT substantially reduces overestimation of the CTVHR volume of CT alone while maintaining similar interobserver variability.
Conclusions: The present study results show that all the dose parameters of HRCTV, bladder, and rectum with 60Co were comparable with those of 192Ir HDR source. The isodose distribution is more bulge out for 60Co in cranial-caudal direction compared to that of 192Ir. However, these differences can be reduced by treatment planning optimization techniques. The clinical plan evaluation in each slice and plane is necessary to explore the logistic and financial benefits of miniaturized 60Co source over 192Ir HDR source.
We presented the physics preparations and clinical workflow required for implementing MRI-based HDR IBT (MRI-HDR-IBT) of gynecologic cancer patients in a high-volume brachytherapy center. The present document is designed to focus on the clinical steps required from a physicist's standpoint. Those steps include: (a) testing IBT equipment with MRI scanner, (b) preparation of templates and catheters, (c) preparation of MRI line markers, (d) acquisition, importation and registration of MRI images, (e) development of treatment plans and (f) treatment evaluation and documentation. The checklists of imaging acquisition, registrat...
Conclusions: In 3D brachytherapy of cervical cancer, GO and IPSA optimizations do not present a significant difference in target dose coverage; nevertheless, IPSA may reduce the maximum dose to normal tissue when compared with GO. PMID: 31523240 [PubMed]
CONCLUSIONS: The first results of treatment with the Axxent eBT device are promising, as no recurrences have been observed and toxicity is very low. eBT is a good alternative for treating cervical cancer in centers without access to conventional HDR. PMID: 31183970 [PubMed - as supplied by publisher]
Conclusions: 3D-HDR-BT achieves favorable clinical outcomes with mild late toxicity in patients with locally rNPC. Introduction Nasopharyngeal carcinoma (NPC), a tumor of epithelial origin, is a malignant disease of the head and neck common in southern China, especially in Guangdong province (1). As a result of advances in modern imaging and irradiation techniques, the 5-year overall survival (OS) of patients with newly diagnosed NPC without metastasis has reached 75% after external beam radiotherapy (EBRT) in Asia (2, 3). However, local recurrence, which occurs in 18–40% of patients, remains a major reason for...
Conclusions: A combination of MRI and CT is a safe alternative approach for cervical cancer HDR brachytherapy. The technique provides comparable dosimetric outcomes to MRI-based planning, while being more cost-effective. PMID: 30479618 [PubMed]
For cervical brachytherapy planning, magnetic resonance imaging (MRI) is preferable to computed tomography (CT) for target delineation. However, due to logistical and financial restrictions, in-room MRI is not routinely available in brachytherapy centers in the United States. Our institution has created a workflow that integrates MRI based target delineation with an in-room CT scanner. After the initial fraction of CT guided brachytherapy is delivered, an MRI is acquired and fused to subsequent planning CT ’s (fractions 2-5) with the aim of improving target coverage and improving conformality.