Dosimetric comparison of 60 Co and 192 Ir high dose rate source used in brachytherapy treatment of cervical cancer

• Published in: Journal of cancer research and therapeutics 2019-10, Vol.15 (6), p.1212
• Main Authors: Shukla, Arvind Kumar, Jangid, Pawan Kumar, Rajpurohit, Vikram Singh, Verma, Atul, Dangayach, Suresh Kumar, Gagrani, Vaibhav, Rathore, Narendra Kumar
• Format: Article
• Language: English
• Subjects: Brachytherapy - adverse effects; Brachytherapy - methods; Cobalt Radioisotopes - administration & dosage; Dose-Response Relationship, Radiation; Female; Humans; Iridium Radioisotopes - administration & dosage; Organs at Risk; Radiometry; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Image-Guided; Tomography, X-Ray Computed; Treatment Outcome; Uterine Cervical Neoplasms - diagnosis; Uterine Cervical Neoplasms - radiotherapy
• ISSN: 0973-1482; 1998-4138
• DOI: 10.4103/jcrt.JCRT_372_19

The study purpose included dosimetric comparison of cobalt 60 ( Co) and iridium 192 ( Ir) high dose rate (HDR) source used in brachytherapy treatment of cervical cancer. Computed tomography (CT) scans for 15 patients of carcinoma of uterine cervix using 3-mm slice thickness were considered for the study The contouring of high-risk clinical target volume (HRCTV), bladder, and rectum on CT images was done as per the GEC ESTRO guidelines with the help of magnetic resonance imaging images in the treatment planning system. All parameters were kept the same for Co (3.5 mm active length, 0.5 mm active dia, Bebig) and Ir (3.5 mm active length, 0.6 mm active dia, Bebig) HDR source with 2.5-mm step size and dose prescription to Point A. As per the International Commission on Radiation Unit (ICRU)-89 guidelines, the dose-volume parameters such as D (Gy), D (Gy), and D (Gy) for HRCTV and D (Gy), D (Gy), D (Gy), and D (Gy) to the bladder and rectum were calculated for both the HDR sources. The difference in dose-volume histogram parameters such as D D and D of HRCTV was 3.19%, 1.13%, and 0.50%, respectively, for the two radioisotopes. The difference in dose values of D , D , D , D , and ICRU reference points of bladder was -0.58%, -0.67%, -0.99%, -0.94%, and -1.75%, respectively. On the other hand, dose difference for D , D , D , D , and ICRU reference points of rectum was 0.67%, 0.26%, 0.56%, 0.63%, and -0.33%, respectively. The present study results show that all the dose parameters of HRCTV, bladder, and rectum with Co were comparable with those of Ir HDR source. The isodose distribution is more bulge out for Co in cranial-caudal direction compared to that of Ir. 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 Co source over Ir HDR source.