புற்றுநோய் அறிவியல் & சிகிச்சை

Dosimetric Analysis of 3D-CT Image Based High Dose Rate Brachytherapy Treatment Planning of Carcinoma Uterine Cervix: Initial Experiences at Central India Government Institute

Abstract

Suresh Yadav, Sanjay Singh Chandel, Choudhary S, Veenita Yogi, Singh OP, Dinesh Kumar Saroj and Goswami Brijesh

Background: Conventionally, the dose calculation of intracavitary brachytherapy (ICBT) is carried out using two dimensional (2D) orthogonal x-ray films. In comparison to conventional 2D, three dimensional (3D) image based planning is providing volumetric dose to target and organ at risks (OARs). Due to logistical reasons, it is not feasible to perform 3D image based brachytherapy planning in resource setting radiotherapy centers.

Aim: This study aimed to analyze the dose volume parameters (DVH) for target and OARs in high dose rate (HDR) ICBT treatment planning of carcinoma uterine cervix (Ca-Cx) patients. Our initial experiences of computed tomography (CT) image based ICBT planning.

Materials and Methods: Retrospectively 39 CT image based plans of 13 patients (total 13x3=39 CT) of Ca-Cx were evaluated, who have already treated with Ir-192 HDR brachytherapy. The dose of 7 Gy/fraction for 3 fractions was prescribed and calculated on point ‘A’. The 100% isodoseline of prescribed dose was adjusted using geometrical tools of treatment planning system (TPS) in such a manner that high risk clinical target volume (HR-CTV) was encompassed by at least 90% of isodose line with keeping OARs doses within tolerance limit. The dose volume parameters HR-CTV D₉₀, HR-CTV D₁₀₀ and average point ‘A’ for target and D_2CC for OARs were calculated and evaluated.

Results and Discussion: The combined mean dose for dosimetric parameters HR-CTV D₉₀, HR-CTV D₁₀₀ and average point ‘A’ were found to be 100.82 Gy (S.D.: ± 6.08), 70.95 Gy (S.D.: ± 2.76) and 79.46 Gy (S.D.: ± 0.66) respectively. The combined D_2CC mean dose of bladder, rectum and sigmoid colon were found to be 68.89 Gy (S.D.: ± 8.76), 63.74 Gy (S.D.: ± 3.82) and 73.20 Gy (S.D.: ± 3.04) respectively.

Conclusion: In a resource setting radiotherapy centers 3D-CT image may be used as a moderate option of imaging for ICBT treatment planning of Ca-Cx.