• Radiation Oncology Journal
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• v.9 no.2
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• pp.337-342
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• 1991

The comparison of the KAPM Dosimetric Protocol (1990) with the TG-21 and $C_{\lambda}/C_E$(ICRU-21 and SCRAD protocol) method is studied. The therapetutic range of radiation (photon 4MV-l5MV and electron 6 MeV-20MeV) and three kinds of the chambers were used in the water phantom. The results from 7G-21 and KAPM protocol did not show much differences (less than 1$\%$) throughout the whole energy range; $N_D$ from KAPM protocol and Ngas from TG-21 showed 0.2$\%$ deviation mainly from W/e difference between two protocols. But the results from KAPM protocol (1990) and those from $C_{\lambda}/C_E$ Method showed $-1.9{\pm}0.6\%$ (KAPM protocol is higher) deviation for photom beam and $+3.3{\pm}1\%$ (KAPM protocol is lower) deviation for electron beams.

• Progress in Medical Physics
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• v.29 no.2
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• pp.73-80
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• 2018

Accelerated partial breast irradiation (APBI) is a new treatment delivery technique that decreases overall treatment time by using higher fractional doses than conventional fractionation. Here, a quantitative analysis study of CyberKnife-based APBI was performed on 10 patients with left-sided breast cancer who had already finished conventional treatment at the Inha University Hospital. Dosimetric parameters for four kinds of treatment plans (3D-CRT, IMRT, VMAT, and CyberKnife) were analyzed and compared with constraints in the NSABP B39/RTOG 0413 protocol and a published CyberKnife-based APBI study. For the 10 patients recruited in this study, all the dosimetric parameters, including target coverage and doses to normal structures, met the NSABP B39/RTOG 0413 protocol. Compared with other treatment plans, a more conformal dose to the target and better dose sparing of critical structures were observed in CyberKnife plans. Accelerated partial breast irradiation via CyberKnife is a suitable treatment delivery technique for partial breast irradiation and offers improvements over external beam APBI techniques.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.270-277
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• 2023

Exposure to ionizing radiation induces free radicals in human nails. These free radicals generate a radiation-induced signal (RIS) in electron paramagnetic resonance (EPR) spectroscopy. Compared with the RIS of tooth enamel samples, that in human nails is more affected by moisture and heat, but has the advantages of being sensitive to radiation and easy to collect. The fingernail as a biological sample is applicable in retrospective dosimetry in cases of localized hand exposure accidents. In this study, the dosimetric characteristics of fingernails were analyzed in fingernail clippings collected from Korean donors. The dose response, fading of radiation-induced and mechanically induced signals, treatment method for evaluation of background signal, minimum detectable dose, and minimum detectable mass were investigated to propose a fingernail-EPR dosimetry protocol. In addition, to validate the practicality of the protocol, blind and field experiments were performed in the laboratory and a non-destructive testing facility. The relative biases in the dose assessment result of the blind and field experiments were 8.43% and 21.68% on average between the reference and reconstructed doses. The results of this study suggest that fingernail-EPR dosimetry can be a useful method for the application of retrospective dosimetry in cases of radiological accidents.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.985-989
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• 2012

Objective: To make sure the feasibility with $^{18F}FDG$ PET/CT to guided dynamic intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma patients, by dosimetric verification before treatment. Methods: Chose 11 patients in III~IVA nasopharyngeal carcinoma treated with functional image-guided IMRT and absolute and relative dosimetric verification by Varian 23EX LA, ionization chamber, 2DICA of I'mRT Matrixx and IBA detachable phantom. Drawing outline and making treatment plan were by different imaging techniques (CT and $^{18F}FDG$ PET/CT). The dose distributions of the various regional were realized by SMART. Results: The absolute mean errors of interest area were $2.39%{\pm}0.66$ using 0.6cc ice chamber. Results using DTA method, the average relative dose measurements within our protocol (3%, 3 mm) were 87.64% at 300 MU/min in all filed. Conclusions: Dosimetric verification before IMRT is obligatory and necessary. Ionization chamber and 2DICA of I'mRT Matrixx was the effective dosimetric verification tool for primary focal hyper metabolism in functional image-guided dynamic IMRT for nasopharyngeal carcinoma. Our preliminary evidence indicates that functional image-guided dynamic IMRT is feasible.

• Progress in Medical Physics
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• v.21 no.4
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• pp.354-359
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• 2010

The purpose of this study is to verify the dosimetric effect on real PTV (planning target volume) coverage and safety of OARs (organs at risk) at various image fusion protocol-based radiosurgery plan for pituitary adenomas. Real PTV coverage and its variation was acquired and maximum dose and the volume absorbing above threshold dose were also measured for verifying the safety of optic pathway and brainstem. The protocol that can reduce superior-inferior uncertainty by using both axial and coronal MR (magnetic resonance) image sets shows relatively lower values than that of case using only axial image sets. As a result, the image fusion protocol with both axial and coronal image sets can be beneficial to generate OAR-weighted radiosurgery plan.

• 대한핵의학회:학술대회논문집
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• 2001.05a
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• pp.4-10
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• 2001

The radionuclide therapy is a protocol for tumor control by administering radionuclides as the cytotoxic agents. Radionuclides concentrated at the site of cancerous lesion are expected to kill the cancerous cells with minimal injury to the normal tissue. The efficacy of every radionuclide treatment can be evaluated by examining the toxicity to the lesion differentiated from that to the normal tissue. Radiation dosimetry is the procedure of quantitating the energy absorbed by target volumes of interest. Dosimetric information plays an indicator of the expected radiation damage and thus the therapeutic efficacy. This paper summarizes the dosimetric aspects in radionuclide therapy in terms of radionuclides of use, radiation dosimetry methodology and considerations for each treatment in practical use.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.11
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• pp.4935-4937
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• 2016

Objective: To compare dosimetric parameters of 3 dimensional conformal radiotherapy (3 DCRT) and intensity modulated radiotherapy (IMRT) in terms of target coverage and doses to organs at risk (OAR) in the management of rectal carcinoma. Methods: In this prospective study, conducted between August 2014 and March 2016, all patients underwent CT simulation along with a bladder protocol and target contouring according to the Radiation Therapy Oncology Group (RTOG) guidelines. Two plans were made for each patient (3 DCRT and IMRT) for comparison of target coverage and OAR. Result: A total of 43 patients were recruited into this study. While there were no significant differences in mean Planning Target Volume (PTV) D95% and mean PTV D98% between 3 DCRT and IMRT, mean PTV D2% and mean PTV D50% were significantly higher in 3 DCRT plans. Compared to IMRT, 3 DCRT resulted in significantly higher volumes of hot spots, lower volumes of cold spots, and higher doses to the entire OAR. Conclusion: This study demonstrated that IMRT achieves superior normal tissue avoidance (bladder and bowel) compared to 3 DCRT, with comparable target dose coverage.

• Progress in Medical Physics
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• v.9 no.4
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• pp.267-276
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• 1998

Any detector inserted into a phantom should have such a geometry that it caused as small as possible perturbation of the electron fluence. Plane parallel chambers meet this requirement better than other chambers of configurations. IAEA protocol recommends the use of plane parallel chambers for this reason. However, the cylindrical chambers are widely used for convenient. The purpose of this study is to evaluate the absorbed dose due to the differences of four different dosimetry protocols such as IAEA protocol using cylindrical chamber, TG 21 protocol using cylindrical chamber, Markus protocol using plane parallel chamber, and TG 39 report for the calibration of plane parallel chamber in electron beams. Depth-ionization measurements for the electron beams of nominal energy 6, 9, 12, 15, and 18 MeV from Siemens accelerator with a 10$\times$10 cm$^2$ field size were made using a radiation field analyser with 0.125 cc ion chamber. Dosimetric measurements by IAEA and TG 21 protocol were made with a farmer type ionization chamber in solid water for each electron energy, respectively. Dosimetric measurements by Markus protocol were made with a plane parallel ionization chamber in solid water for each electron energy, respectively. The cavity-gas calibration factor for the plane parallel chamber was obtained with the use of 18 MeV electron beam as guided by TG 39 report. Dosimetric measurements by TG 39 were performed with a plane parallel ionization chamber in solid water for each electron energy, respectively. For all the energies and protocols, measurements were made along the central axis of the distance of 100 cm (SSD = 100 cm) with 10$\times$10 cm$^2$ field size at the depth of d$_{max}$ for each electron beam, respectively. In the case of 18 MeV, the discrepancy of 0.9 % between IAEA and TG 21 was found and the two protocols were agreed within 0.7 % for other energies. In the case of 18 MeV and 6 MeV, the discrepancies of $\pm$ 0.8 % between Markus and TG 39 was found, respectively and the two protocols were agreed within 0.5 % for other energies. Since the discrepancy of 1.6 % between cylindrical and plane parallel chamber was found for 18 MeV, it is suggested to get the calibration factor using other method as guided. by TG 39.9.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.429-436
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• 2022

Investigations of retrospective dosimetry have shown that components of mobile phones are suitable as emergency dosimeters in case of radiological incidents. For physical dosimetry, components can be read out using optically stimulated luminescence (OSL), thermoluminescence (TL) and phototransferred thermoluminescence (PTTL) methods to determine the absorbed dose. This paper deals with a feasibility study of display glass from modern mobile phones that are measured by thermally assisted (Ta) optically stimulated luminescence. Violet (VSL, 405 nm) and infrared (IRSL, 850 nm) LEDs were used for optical stimulation and two protocols (Ta-VSL and Ta-IRSL) were tested. The aim was to systematically investigate the luminescence properties, compare the results to blue stimulated Ta-BSL protocol (458 nm) and to develop a robust measurement protocol for the usage as an emergency dosimeter after an incident with ionizing radiation. First, the native signals were measured to calculate the zero dose signal. Next, the reproducibility and dose response of the luminescence signals were analyzed. Finally, the signal stability was tested after the storage of irradiated samples at room temperature. In general, the developed Ta-IRSL and Ta-VSL protocols indicate usability, however, further research is needed to test the potential of a new protocol for physical retrospective dosimetry.

• Radiation Oncology Journal
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• v.35 no.4
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• pp.368-379
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• 2017

Purpose: The purpose of this study was to explore the dosimetric difference between simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) and three-dimensional conformal radiotherapy (3DCRT), and the clinical outcomes of anal squamous cell carcinoma (ASCC) chemoradiotherapy featuring SIB-IMRT. Materials and Methods: This study included ten patients with ASCC who underwent chemoradiotherapy using SIB-IMRT with 5-fluorouracil and mitomycin C. SIB-IMRT delivered 54 Gy to each primary tumor plus metastatic lymph nodes and 45 Gy to regional lymph nodes, in 30 fractions. Four patients received additional boosts to the primary tumors and metastatic lymph nodes; the median total dose was 54 Gy (range, 54 to 60 Gy). We additionally created 3DCRT plans following the Radiation Therapy Oncology Group 9811 protocol to allow dosimetric comparisons with SIB-IMRT. Locoregional control, overall survival, and toxicity were calculated for the clinical outcome evaluation. Results: Compared to 3DCRT, SIB-IMRT significantly reduced doses to the external genitalia, bladder, and intestine, delivering the doses to target and elective nodal region. At a median follow-up time of 46 months, 3-year locoregional control and overall survival rates were 88.9% and 100%, respectively. Acute toxicities were treated conservatively. All patients completed radiotherapy with brief interruptions (range, 0 to 2 days). No patient experienced ${\geq}grade$ 3 late toxicity during the follow-up period. Conclusion: The dosimetric advantages of SIB-IMRT appeared to reduce the toxicity of chemoradiotherapy for ASCC achieving high locoregional control in the extended period.