Recently, Enzhuo Quan et al. from the Radiation Physics Department at MD Anderson Cancer Center published a study of a postural fixation protocol for stereotactic radiation therapy (SBRT) of spinal tumours in the Journal of Applied Clinical Medical Physics. The researchers selected two commonly used SBRT fixation Solutions, the Klarity SBRT System and the Elekta BodyFIX System, to conduct a comparative study on initial setup accuracy, set-up stability & efficiency, and operational convenience for medical staff.

The study, derived from an internal study (IRB pa2018-1096) of MD Anderson Cancer Center, enrolled 23 patients with 26 metastatic spinal lesions, using the Klarity SBRT System or the BodyFIX System. 11 patients (14 lesions) were treated with the BodyFIX System. The other 12 patients (12 lesions) were treated with the Klarity SBRT System. Patients with cervical and thoracic spine tumours were excluded from the included patients, as these patients are usually treated with head-neck-shoulder immobilization.

· In this study, the two immobilization systems showed similar magnitude in the table corrections along the longitudinal and three rotational directions in the initial ExacTrac based table corrections after skin-mark alignment (all p-value > 0.05), but in the lateral and vertical directions, the BodyFix system is better than Klarity SBRT System. (Section I)

· In the subsequent image-guided setup procedure after the first table corrections were applied, no significant difference (all p values > 0.05) were observed in the maximum magnitude of positional deviations between two systems. (Section II)

· After the completion of the irradiation treatment, CBCT was used to verify the stability of the patient's treatment position within the fraction. The verification results showed that there was no significant difference in any of the translational or rotational directions between the two immobilization solutions (all p-value > 0.05) (Section III).

Ultimately, this study concludes that the Klarity SBRT System can provide accurate and efficient patient immobilization. Although larger vertical and lateral initial table corrections were needed with the Klarity System, the overall setup accuracy, setup efficiency, and intra-fractional stability were comparable to the BodyFIX system. T. Klarity SBRT System is a promising alternative to the BodyFIX system for Spine SBRT while providing potential workflow benefits depending on one’s practice environment.

More details, please refer to the full article: https://aapm.onlinelibrary.wiley.com/doi/10.1002/acm2.13804