Dosimetric characterization of an image-guided stereotactic small animal irradiator

Pidikiti, Rajesh; Stojadinović, Strahinja; Speiser, M.; Song, Kwang Hyun; Hager, F; Saha, Debabrata; Solberg, Timothy D.

doi:10.1088/0031-9155/56/8/016

Cited by 60 publications

(63 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In contrast to conventional radio therapy, which delivers low dose to a larger volume for a higher number of daily fractions, SABR is usually given as a single dose or up to five doses once a day with tumor ablation and maximal normal-tissue sparing. [2][3][4][5][6] Despite these advantages, it could lead a more severe damage compared to conventional therapy if the positioning error occurred.…”

Section: Introductionmentioning

confidence: 99%

Effect of Low Magnetic Field on Dose Distribution in the SABR Plans for Liver Cancer

Son

Chun

et al. 2018

Prog Med Phys

View full text Add to dashboard Cite

To investigate the effect of low magnetic field on dose distribution in SABR plans for liver cancer, we calculated and evaluated the dose distribution to each organ with and without magnetic fields. Ten patients received a 50 Gy dose in five fractions using the ViewRay ® treatment planning system. For planning target volume (PTV), the results were analyzed in the point minimum (D min ), maximum (D max ), mean dose (D mean ) and volume receiving at least 90% (V 90% ), 95% (V 95% ), and 100% (V 100% ) of the prescription dose, respectively. For organs at risk (OARs), the duodenum and stomach were analyzed with D 0.5cc and D 2cc , and the remained liver except for PTV was analyzed with D mean , D max , and D min . Both inner and outer shells were analyzed with the point D min , D max , and D mean , respectively. For PTV, the maximum change in volume due to the presence or absence of the low magnetic field showed a percentage difference of up to 0.67±0.60%. In OAR analysis, there is no significant difference for the magnetic field. In both shell structure analyses, although there are no major changes in dose distribution, the largest value of deviation for D max in the outer shell is 2.12±2.67 Gy. The effect of low magnetic field on dose distribution by a Co-60 beam was not significantly observed within the body, but the dose deposition was only appreciable outside the body.

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of Low Magnetic Field on Dose Distribution in the SABR Plans for Liver Cancer

Son

Chun

et al. 2018

Prog Med Phys

View full text Add to dashboard Cite

show abstract

“…There are specific small animal irradiators designed especially for preclinical studies, used to evaluate and optimize new treatment modalities (3,4). Delineating set-up protocols with the equipment (linear accelerators) used clinically for patient treatments is a slow process, and using these irradiators for cells and small animal experiments in the preliminary stages of research would save time.…”

Section: Introductionmentioning

confidence: 99%

Biological X-ray irradiator characterization for use with small animals and cells

Bruno

Mazaro

Amaral

et al. 2017

Braz J Med Biol Res

View full text Add to dashboard Cite

This study presents the characterization of an X-ray irradiator through dosimetric tests, which confirms the actual dose rate that small animals and cells will be exposed to during radiobiological experiments. We evaluated the linearity, consistency, repeatability, and dose distribution in the positions in which the animals or cells are placed during irradiation. In addition, we evaluated the performance of the X-ray tube (voltage and tube operating current), the radiometric survey (leakage radiation) and safety devices. The irradiator default setting was established as 160 kV and 25 mA. Tests showed that the dose rate was linear overtime (R2=1) and remained stable for long (constant) and short (repeatability) intervals between readings. The mean dose rate inside the animal cages was 1.27±0.06 Gy/min with a uniform beam of 95.40% (above the minimum threshold guaranteed by the manufacturer). The mean dose rate inside the cell plates was 0.92±0.19 Gy/min. The dose rate dependence with tube voltage and current presented a quadratic and linear relationship, respectively. There was no observed mechanical failure during evaluation of the irradiator safety devices and the radiometric survey obtained a maximum ambient equivalent dose rate of 0.26 mSv/h, which exempts it from the radiological protection requirements of the International Atomic Energy Agency. The irradiator characterization enables us to perform radiobiological experiments, and assists or even replaces traditional therapy equipment (e.g., linear accelerators) for cells and small animal irradiation, especially in early research stages.

show abstract

“…A high-resolution 3D dose readout is desired for radiotherapy treatments given by small animal irradiators, as well as for verification of treatment planning software, which is becoming more widely available. [13][14][15][16] In this work, high-resolution rodent-morphic Presage radiochromic dosimeters (Heuris Inc., Skillman, NJ) were produced utilizing 3D printing technology in order to investigate the accuracy of end-to-end image-guided microstereotactic body radiation therapy (SBRT) arc treatment given by the X-Rad 225Cx microirradiator. We investigate (i) the feasibility of utilizing 3D printing in order to produce rodent-morphic Presage 3D dosimeters (including high-Z spinal inserts) directly from CT contours, (ii) the feasibility of optical-CT 3D dosimetry in these dosimeters exhibiting complex irregular shapes, and (iii) the application of (i) and (ii) to the verification of microSBRT treatments and comparison against independent dosimeters (EBT film and a novel scintillation point dose detector).…”

Section: Introductionmentioning

confidence: 99%

Investigating the accuracy of microstereotactic‐body‐radiotherapy utilizing anatomically accurate 3D printed rodent‐morphic dosimeters

et al. 2015

View full text Add to dashboard Cite

Purpose: Sophisticated small animal irradiators, incorporating cone-beam-CT image-guidance, have recently been developed which enable exploration of the efficacy of advanced radiation treatments in the preclinical setting. Microstereotactic-body-radiation-therapy (microSBRT) is one technique of interest, utilizing field sizes in the range of 1-15 mm. Verification of the accuracy of microSBRT treatment delivery is challenging due to the lack of available methods to comprehensively measure dose distributions in representative phantoms with sufficiently high spatial resolution and in 3 dimensions (3D). This work introduces a potential solution in the form of anatomically accurate rodent-morphic 3D dosimeters compatible with ultrahigh resolution (0.3 mm 3 ) optical computed tomography (optical-CT) dose read-out. Methods: Rodent-morphic dosimeters were produced by 3D-printing molds of rodent anatomy directly from contours defined on x-ray CT data sets of rats and mice, and using these molds to create tissue-equivalent radiochromic 3D dosimeters from Presage. Anatomically accurate spines were incorporated into some dosimeters, by first 3D printing the spine mold, then forming a high-Z bone equivalent spine insert. This spine insert was then set inside the tissue equivalent body mold. The high-Z spinal insert enabled representative cone-beam CT IGRT targeting. On irradiation, a linear radiochromic change in optical-density occurs in the dosimeter, which is proportional to absorbed dose, and was read out using optical-CT in high-resolution (0.5 mm isotropic voxels). Optical-CT data were converted to absolute dose in two ways: (i) using a calibration curve derived from other Presage dosimeters from the same batch, and (ii) by independent measurement of calibrated dose at a point using a novel detector comprised of a yttrium oxide based nanocrystalline scintillator, with a submillimeter active length. A microSBRT spinal treatment was delivered consisting of a 180• continuous arc at 225 kVp with a 20 × 10 mm field size. Dose response was evaluated using both the Presage/optical-CT 3D dosimetry system described above, and independent verification in select planes using EBT2 radiochromic film placed inside rodent-morphic dosimeters that had been sectioned in half. Results: Rodent-morphic 3D dosimeters were successfully produced from Presage radiochromic material by utilizing 3D printed molds of rat CT contours. The dosimeters were found to be compatible with optical-CT dose readout in high-resolution 3D (0.5 mm isotropic voxels) with minimal artifacts or noise. Cone-beam CT image guidance was possible with these dosimeters due to sufficient contrast between high-Z spinal inserts and tissue equivalent Presage material (CNR ∼10 on CBCT images). Dose at isocenter measured with optical-CT was found to agree with nanoscintillator measurement to within 2.8%. Maximum dose in line profiles taken through Presage and film dose slices agreed within 3%, with FWHM measurements through each profile found to agree within 2%. Conclusions: T...

show abstract

Dosimetric characterization of an image-guided stereotactic small animal irradiator

Cited by 60 publications

References 44 publications

Effect of Low Magnetic Field on Dose Distribution in the SABR Plans for Liver Cancer

Effect of Low Magnetic Field on Dose Distribution in the SABR Plans for Liver Cancer

Biological X-ray irradiator characterization for use with small animals and cells

Investigating the accuracy of microstereotactic‐body‐radiotherapy utilizing anatomically accurate 3D printed rodent‐morphic dosimeters

Contact Info

Product

Resources

About