A three-field arc technique (3-FAT) for treating prostate cancer

Area of Science:

• Radiation Oncology
• Medical Physics
• Oncology

Background:

• External beam radiotherapy is a primary treatment for prostate cancer.
• Previous techniques include seven-field coplanar fixed beams and bilateral blocked arcs, each with distinct advantages and disadvantages.
• Optimizing dose distribution to target the clinical target volume (CTV) while sparing critical structures is crucial.

Purpose of the Study:

• To develop and evaluate a novel three-field arc technique (3-FAT) for prostate cancer radiotherapy.
• To improve dose delivery to the CTV.
• To minimize radiation dose to adjacent organs at risk: rectum, bladder, and femoral heads.

Main Methods:

• A comparative study involving 20 prostate cancer patients previously treated with radiotherapy.
• The new 3-FAT was designed using two rotational beams and an anterior inferior oblique beam, with specific gantry and table angles.
• Dose distributions were evaluated using dose-volume histograms (DVH) and compared against seven-field coplanar and four-field noncoplanar fixed beam techniques.

Main Results:

• The 3-FAT demonstrated superior dose distributions for critical structures.
• Compared to the seven-field plan, 3-FAT reduced rectal dose by 13% and bladder dose by 25% to 40% of the volume.
• 3-FAT reduced femoral head dose by approximately 45% compared to other techniques, with even greater improvements over standard methods.

Conclusions:

• The 3-FAT represents a significant technical advancement in prostate cancer radiotherapy.
• This technique effectively minimizes radiation dose to the rectum, bladder, and femoral heads.
• The 3-FAT is compatible with modern technologies like multileaf collimation for cost-effective and efficient treatment delivery.