Development of an Angiography Guide Indicator for Stereotactic Radiosurgery for High Precision.

BACKGROUND: Stereotactic radiosurgery (SRS) is effectively used for treating various cerebrovascular diseases, including arteriovenous malformations. As image-based surgery is the gold standard technique in SRS, the quality of stereotactic angiography images greatly influences the surgical approach for cerebrovascular diseases. Despite several studies in the relevant literature, research on auxiliary devices, including angiography indicators used for cerebrovascular disease surgeries, is limited. Thus, the development of angiographic indicators may provide meaningful data for stereotactic surgery. METHODS: A centerline was drawn, and a guideline was attached such that the "+" and "X" centers of the existing angiography guide indicator intersect. Further, a guideline wire connecting "+" and "X" was fixed using a tape. Based on the presence or absence of the guide indicator, angiography anterior-posterior (AP) and lateral (LAT) images were taken 10 times each, and statistical analysis was performed. RESULTS: The average and standard deviation of the conventional AP and LAT indicators were 10.22 ± 0.53 mm and 9.02 ± 0.33 mm, and those of the developed AP and LAT indicators were 10.3 ± 0.57 mm and 8.92 ± 0.23 mm, respectively. CONCLUSIONS: The results confirmed that the use of the lead indicator developed in this study provides higher accuracy and precision compared to that of the use of the conventional indicator. Furthermore, the developed guide indicator may provide meaningful information during SRS.

Development of an Animal Stereotactic Device for Preclinical Research on Tumor Response After Stereotactic Radiosurgery.

BACKGROUND: In gamma knife radiosurgery, the tumor response to radiation is an important predictor of clinical treatment results. Since brain tumors have different characteristics and growth patterns, depending on the type, the tumors' response to radiation are also different. Compared with various other clinical treatments, there is a dearth of research on the development of gamma knife-magnetic resonance imaging (MRI) preclinical experimental equipment. Hence, the identification of preclinical equipment necessity for experimental animals will provide meaningful data for the provision of clinical assistance to humans. OBJECTIVES: A device for stereotactic radiosurgery capable of MRI in small animals was developed. The feasibility of creating a preplan by means of small animal images was then assessed. METHODS: A device for stereotaxic surgery of small animals using a 48-channel MRI coil was developed using a 3 dimensional printer. Rat brain-MRI images were obtained with a 3.0 T MRI scanner using a multi-channel coil. The acquired MRI images were transferred to a GammaPlan workstation to establish a preplan. RESULTS: To gamma rays to the targeted site on animals, a positioning device combined with a G-frame was mounted on a gamma knife. Planning of radiosurgery based on MRI images became possible with GammaPlan workstations. CONCLUSIONS: Preclinical experiments using small animals are possible with the use of stereotactic devices. In clinical treatment, preclinical experimental results will provide meaningful information.

Development of a Stereotactic Radiosurgery Frame Adapter for a Multichannel MRI Coil.

BACKGROUND: The usage of multichannel brain MRI coils, which have several advantages over single-channel brain coils used for stereotactic radiosurgery (SRS), requires a frame adapter device to fit the frames inside the multichannel brain coils. However, such a frame adapter has not been developed until now. OBJECTIVE: to develop an SRS frame adapter for multichannel MRI coils and verify the geometrical accuracy and signal-to-noise ratio (SNR) of the MR images obtained using multichannel MRI coils. METHODS: We fabricated an SRS frame adapter for a 48-channel MRI coil using a three-dimensional (3D) printer. Furthermore, we obtained phantom and human-brain MR images with a 3.0 Tesla MRI scanner using multi- and single-channel coils. Computed tomography (CT) phantom images were also obtained as reference. We compared the coordinate errors of the multi- and single-channel coils to evaluate the geometrical accuracy. Two neurosurgeons measured the coordinates. In addition, we compared the SNR differences between multi- and single-channel coils using the T1- and T2-weighted brain images. RESULTS: For the CT coordinate measurements, the correlation coefficient r = 1 and p < 0.001 with respect to the 3 axes (Δx, Δy, and Δz) and 3D errors (Δr) showed no interpersonal differences between the 2 neurosurgeons. The results obtained using the T1-weighted images showed that a multichannel coil had smaller coordinate errors in Δx, Δy, Δz, and Δr than that observed in case of a single-channel coil (p < 0.001). In case of the SNR measurements, most of the brain areas showed higher SNRs when using a multichannel coil compared with that observed when using a single-channel coil in the T1- and T2-weighted images. CONCLUSION: Compared with single-channel coils, the use of multichannel MRI coils with a newly developed frame adapter is expected to ensure successful SRS treatments with improved geometrical accuracy and SNR.