Treating lung cancer with dynamic conformal arc therapy: a dosimetric study

Area of Science:

• Radiation Oncology
• Medical Physics

Background:

• Lung cancer patients often have poor physical condition, necessitating shorter treatment times.
• Dynamic conformal arc therapy (DCAT) offers reduced treatment duration compared to 3D conformal radiotherapy (3D CRT).
• DCAT is accessible in facilities lacking inverse planning capabilities.

Purpose of the Study:

• To evaluate the suitability of DCAT as a lung cancer treatment modality.
• To compare dosimetric parameters between DCAT and 3D CRT treatment plans.
• To assess the accuracy of DCAT and 3D CRT dose distributions using film dosimetry.

Main Methods:

• A cohort of 35 lung cancer patients was analyzed.
• Dosimetric parameters of DCAT and 3D CRT plans were compared.
• Radiochromic film dosimetry in an anthropomorphic phantom validated planned dose distributions.

Main Results:

• DCAT plans demonstrated equal or superior agreement between planned and measured doses compared to 3D CRT.
• DCAT showed better dose conformity to the planning target volume (PTV) and fewer monitor units.
• 3D CRT generally yielded better dose homogeneity, lower mean lung dose, and reduced lung V5Gy.

Conclusions:

• DCAT is a reliable radiotherapy technique, comparable to 3D CRT in dose distribution accuracy.
• DCAT may offer dosimetric advantages in specific patient anatomies and prescriptions.
• Conventional 3D CRT typically provides superior average dosimetric parameters, positioning DCAT as a complementary technique.