Kilovoltage radiotherapy for companion animals: dosimetric comparison of 300 kV, 450 kV, and 6 MV X-ray beams

Abstract

Radiotherapy for the treatment of cancer in companion animals is currently administered by using megavoltage X-ray machines. Because these machines are expensive, most animal hospitals do not perform radiotherapy. This study evaluated the ability of relatively inexpensive kilovoltage X-ray machines to treat companion animals. A simulation study based on a commercial treatment-planning system was performed for tumors of the brain (non-infectious meningoencephalitis), nasal cavity (malignant nasal tumors), forefoot (malignant muscular tumors), and abdomen (malignant intestinal tumors). The results of kilovoltage (300 kV and 450 kV) and megavoltage (6 MV) X-ray beams were compared. Whereas the 300 kV and 6 MV X-ray beams provided optimal radiation dose homogeneity and conformity, respectively, for brain tumors, the 6 MV X-rays provided optimal homogeneity and radiation conformity for nasal cavity, forefoot, and abdominal tumors. Although megavoltage X-ray beams provided better radiation dose distribution in most treated animals, the differences between megavoltage and kilovoltage X-ray beams were relatively small. The similar therapeutic effects of the kilovoltage and 6 MV X-ray beams suggest that kilovoltage X-ray beams may be effective alternatives to megavoltage X-ray beams in treating cancers in companion animals.

Comparison of epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2) immunohistochemical expression and outcomes in canine nasal carcinomas treated with radiation therapy

“…Currently, most of veterinary radiation oncology facility are using megavoltage radiation machine. Megavoltage radiation has greater penetrability and dose distribution and would be expected to be superior to orthovoltage RT for nasal tumors in dogs [ 29 ]. This phenomenon is particularly evident in tumors located at greater depths from the skin surface.…”

External beam radiation therapy with kilovoltage x-rays

“…In 2018, Seo et al published an article investigating the treatment of cancer in companion animals (canines) with 300 and 450 kV x-rays [28]. The authors used numerical methods to calculate dose distributions using 300 kV, 450 kV and 6 MV photons for brain, nasal cavity, forefoot and abdomen cancers in companion animals.…”

Improving animal-specific radiotherapy quality assurance for kilovoltage X-ray radiotherapy using a 3D printed dog skull water phantom

“…Kilovoltage X-rays delivered via orthovoltage equipment (Philips Medical Systems, Best, The Netherlands) for small animal radiotherapy are widely used in facilities ranging from clinics to university hospitals ( Pampena et al , 2016 ; Seo et al , 2018 ). The use of linear accelerators for animal radiotherapy has increased in some facilities but remains rare due to high costs and large machine sizes ( Seo et al ., 2018 ). The absorbed dose during orthovoltage radiotherapy may be measured using water procedures ( Ma et al , 2001 ) to ensure that the prescribed doses for soft tissue are accurate.…”