Authors: Thomas G. Lo Greco, MS, RT(R)(T)^∗, Kristen Vu, MS, CMD, RT(T)

Medical Dosimetry Graduate Program, Grand Valley State University, Allendale, Michigan

Kilovoltage computed tomography plays a crucial role in radiotherapy planning. However, the presence of high-density metallic objects can introduce streaking artifacts in CT scans, resulting in inaccurate dose calculations by the treatment planning software. Previous studies have explored manual density overrides and artifact reduction algorithms individually to enhance dose calculation accuracy, but their combined application on patient plans within a treatment planning system remains unexplored. This research aims to assess the necessity of manual density overrides when an artifact reduction algorithm is already employed to address dental artifacts in oropharyngeal cancer treatment plans. A total of 20 previously treated volumetric modulated arc therapy plans were collected, and manual density overrides were removed followed by plan recalculation. Dosimetric parameters were then compared between the original and modi?ed plans. Statistical analysis revealed several dosimetric parameters for the planning target volume (PTV), clinical target volume (CTV), and oral cavity that exhibited statistically signi?cant differences upon removing the manual density override. However, these differences were found to be small in absolute terms. No other organs evaluated demonstrated statistically signi?cant differences in dose. The most signi?cant disparity observed was an 8.26 cGy increase in mean dose to the CTV, which represents only 0.12% of the prescription dose. Based on these ?ndings, it can be concluded that manual density overrides are likely unnecessary when an artifact reduction algorithm is employed in oropharyngeal cancer cases.

As of January 1, 2022, ARRT requires CE Credits for Directed Journal Readings to be based on the word count for each article. So, the number of CE Credits for each DJR article will vary for ARRT. For this article, the ARRT CE Credit will be 0.75 Credit. The MDCB CE Credits will remain at 2.5 Credits.

ARRT CQR Credit Distribution

CT
Image Production 2017
    Image Evaluation and Archiving = 0.5
Radiation Therapy 2017:
Procedures   
      Treatments Volume Localization= 0.5
      Prescription and Dose Calculation = 0.75

CT
Image Production 2022
    Image Evaluation and Archiving = 0.5

Radiation Therapy 2022:
Procedures   
      Treatments Volume Localization= 0.5
      Prescription and Dose Calculation = 0.75