Assessment of Calculated Radiation Dose Via In-house Program and Measured Radiation Dose

Abstract

Background: Treatment planning in radiation therapy is critical to patient recovery and complications. Therefore, the radiation delivery time must be calculated to ensure patients receive the prescribed dose as accurately as possible. The researcher developed a calculation program using Microsoft Excel in three-dimensional treatment planning for patients with pelvic region in the Radiation Oncology Unit of Lop Buri Cancer Hospital. Objective: To evaluate the accuracy of a radiation dose calculation program developed in-house comparing with the actual radiation dose measured using an ionization chamber in a water phantom. Method: This was a quasi-experimental study involving a sample of 100 3D radiation treatment plans for cancer patients. The research instruments included the in-house developed calculation program, Varian Vital Beam linear accelerator, a Farmer-type cylindrical ionization chamber (serial number 0744), radiation measuring cables, a PTW Freiberg Unidos electrometer, a Med Tech MT-DDA water phantom, and a data recording form. Data were collected by recording the calculated radiation doses from the developed program based on the treatment plans and the actual measured radiation doses for each plan between August 1, 2024, and November 30, 2024.The calculated and measured radiation dose values were analyzed using the paired t-test. Result: The calculated radiation doses using the developed program were close to the actual measured radiation doses at all depths and field sizes, with differences not exceeding 1 cGy. Statistical analysis using the Paired t-test revealed no significant differences at a 95% confidence level (p-value > .05). Conclusion: The actual measured doses from the monitor unit settings obtained from the in-house program were found to be comparable to the prescribed doses, with no statistically significant differences at a 95% confidence level. It can be concluded that the accuracy of the radiation dose calculations from the in-house developed program is reliable, precise, and applicable for practical use.