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Bindal A, Mittal P, Shinghal A, Scaria L, Prajapati K, Swamidas J, Gurram L, Berger D, Sturdza A, Chopra S. Sigmoid dose accumulation and reporting for multifractionated brachytherapy for cervical cancer: Methodological development of sigmoid points through virtual endoscopic method. Brachytherapy 2023; 22:325-333. [PMID: 36882345 DOI: 10.1016/j.brachy.2023.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/09/2022] [Accepted: 01/13/2023] [Indexed: 03/07/2023]
Abstract
PURPOSE The sigmoid is an important organ at risk for gynecological brachytherapy (BT). However, the reliability of localization of high-dose regions during multi-fractionated treatment is limited. This work reports the methodological development of sigmoid points to summate multi-fractionated doses. METHODS AND MATERIAL Ten paired MRI data sets of ring-based intracavitary brachytherapy were obtained. Simulating a virtual endoscope, a reference line was created along the central axis of the anorectosigmoid for each implant. A trendline was generated, and linear dose was determined. Three-dimensional (3D) coordinates of high-dose regions were identified, and overlap was determined. In the next step, 3D coordinates of high-dose sigmoid points were localized in reference to cervical os and re-verified for location in reference to sigmoid lumen and corroboration with 2cc doses. With minor modifications, sigmoid points were proposed. RESULTS In 6 of 10 patients, high-dose regions co-localized in subsequent fractions of BT. Three high-dose regions were identified along the sigmoid length and proposed as sigmoid points in reference to cervical os. (S1'= 0.5 cm right, 1.5 cm posterior, and 2.4 cm cranial; S2' = 0.3 cm anterior and 4.5 cm cranial; S3' = 2.7 cm left, 3 cm anterior, and 3.6 cm cranial to the cervical os). S1' and S2' were located in the sigmoid in 70% and 60% of data sets. The mean difference between D2cc and S1'/S2' was 0.30 Gy and 1.06 Gy respectively. S3' had limited corroboration to sigmoid lumen or 2 cc doses. The points S1' and S2' were further modified (minor) for applicability and proposed as sigmoid points 1 and 2 (SP1 0.5 right,1.5 posterior and 2.5 cm cranial to cervical os and SP2 (0.5 cm anterior and 4.5 cm cranial to cervical os)). CONCLUSION SP1 and SP 2 are proposed as a surrogate for 2 cc sigmoid doses and may provide a method of reliable inter-fraction dose summation. This pilot work requires further validation.
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Affiliation(s)
- Arpita Bindal
- Department of Radiation Oncology and Medical Physics, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Prachi Mittal
- Department of Radiation Oncology and Medical Physics, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Abhishek Shinghal
- Department of Radiation Oncology and Medical Physics, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Libin Scaria
- Department of Radiation Oncology and Medical Physics, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Kunal Prajapati
- Department of Radiation Oncology and Medical Physics, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Jamema Swamidas
- Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Lavanya Gurram
- Department of Radiation Oncology and Medical Physics, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Daniel Berger
- Department of Radiation Oncology and Medical Physics, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Alina Sturdza
- Department of Radiation Oncology and Medical Physics, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Supriya Chopra
- Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India.
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