• Progress in Medical Physics
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• v.33 no.4
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• pp.37-52
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• 2022

Over the past decades, radiation therapy combined with imaging modalities that ensure optimal image guidance has revolutionized cancer treatment. The two major purposes of using imaging modalities in radiotherapy are to clearly delineate the target prior to treatment and set up the patient during radiation delivery. Image guidance secures target position prior to and during the treatment. High quality images provide an accurate definition of the treatment target and the possibility to reduce the treatment margin of the target volume, further lowering radiation toxicity and improving the quality of life of cancer patients. In this review, the various types of image guidance modalities used in radiation therapy are distinguished into ionized (kilovoltage and megavoltage image) and nonionized imaging (magnetic resonance image, ultrasound, surface imaging, and radiofrequency). The functional aspects, advantages, and limitation of imaging using these modalities are described as a subsection of each category. This review only focuses on the technological viewpoint of these modalities and any clinical aspects are omitted. Image guidance is essential, and its importance is rapidly increasing in modern radiotherapy. The most important aspect of using image guidance in clinical settings is to monitor the performance of image quality, which must be checked during the periodic quality assurance process.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.85-92
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• 2017

purpose: Image Guide System offers therapy precise, especially Intensity Modulated Radiation Therapy. However, organs at pelvis have variation and uncertainties each therapy. it brings IG system for verifying patient's position. In this study, analysis the variation at pelvis during rectal cancer radiation therapy. Moreover design the patient re-setup technique and apply to patients. Material and Method: 40 rectal cancer patient who have radiation therapy. The 530 image which acquired from IG system are analyzed. The bone structure, bladder, gas in the rectum, small bowel, soft tissue, weigh loss are evaluated by the criterion. The criterion are classified by best, good, bad and figure out the ratio with count. The re-setup proceed in case of one or over the two get the bad criterion and figure out the ratio of re-setup results: The ideal of therapy ratio is 19.2 % each criterion. And the good for therapy ratio is 54.9 %, the cases of bad for therapy is 25.8 %. The bad cases are have therapy after re-setup with post process. conclusion: Each pre-treatment image that acquired IG system has different results despite of same patients. The 25.8 % need to re-setup in order to unsuitable therapy. It is implies that the IG system is necessary establishing precise treatment plan like IMRT especially rectal cancer.

• Radiation Oncology Journal
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• v.25 no.2
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• pp.101-108
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• 2007

[ $\underline{Purpose}$ ]: To compare radiation therapy alone to combined modality therapy about survival rate and tolerance of elderly patients ($70=or{\geq}$) with non-small-cell lung cancer (NSCLC). $\underline{Materials\;and\;Methods}$: Between 1998 and 2002, 57 patients given radiation therapy due to NSCLC (Stage III) were analysed retrospectively. Radiation therapy alone (RT), concurrent chemoradiation (CRT), and sequential chemoradiation (SCRT) was done to 33, 16 and 8 patients, respectively. Patients' median age was 74 (range $70{\sim}85$). Male and female are 51 patients and 6 patients, respectively. 23 patients were stage IIIa and 34 were stage IIIb. Patients' characteristic distribution of RT and CRT was not significantly different except mass size that RT has a bigger than CRT. The fraction size of radiation therapy was 1.8 Gy in CRT and $1.8{\sim}3\;Gy$ in other groups. Total radiation dose was $51{\sim}63\;Gy$ according to the fraction size. If the prescribed total radiation dose was successfully irradiated, we stated that it was completion of radiation therapy. $\underline{Results}$: 52 patients were dead. Median period of radiation therapy was as follow: RT, 35 days, CRT, 60.5 days and SCRT, 35 days. Overall median survival time (MST) was 10.1 months. The 1 yr- and 2 yr-overall survival rate was 39.8% and 17.6%, respectively. MST of RT, CRT and SCRT was 8.9, 8.2 and 11.7 months, respectively. The 1 yr survival rate of RT, CRT and SCRT was 38.4%, 37.5% and 50% (not significant). Patients given incomplete radiation therapy were 12 (RT, 5 CRT, 6 SCRT, 1). N stage (p=0.081) and the difference of treatment methods (p=0.079) were the factors affecting incompletion of radiation therapy, but it was not significant. In case of combined-agents chemotherapy, 4 of 8 ceased radiation therapy. T stage ($T{\geq}3$), mass size (${\geq}5\;cm$), Karnofsky performance scale (${\leq}70$) and completion of radiation therapy were the prognostic factors in uni- and multi-variate analysis. $\underline{Conclusion}$: In elderly patients with NSCLC, radiation therapy alone was a treatment method with similar survival period compared with other methods. Generally, patients given radiation therapy alone was tolerable to a treatment. Before planning concurrent chemoirradiation in elderly patients with NSCLC, physicians pay attention to a selection of patients and chemotherapy agents considering general condition and toxicity.

• Archives of Plastic Surgery
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• v.38 no.6
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• pp.803-807
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• 2011

Purpose: The safety of radiation therapy after breast reconstruction using transverse rectus abdominis myocutaneous (TRAM) flap is still being debated, and few studies exist on the outcome of irradiation after immediate TRAM breast reconstruction. Some authors presented satisfactory outcomes after adjuvant radiation therapy on reconstructed breast with pedicled TRAM flap, while others reported significant post radiation changes of the flap. Effect of radiation therapy on TRAM flap was evaluated to see whether adjuvant radiation therapy was tolerable. Methods: 1000 immediate TRAM breast reconstruction was done by a single surgeon from July, 2001 to December, 2009. Among them 105 patients required adjuvant radiation therapy because of advanced disease or locoregional recurrence. Fat necrosis, radiation fibrosis, mastectomy skin flap necrosis, need for secondary touch up procedures, patient satisfaction were evaluated. Results: The incidence of fat necrosis was 10.5% and significant radiation fibrosis occurred in only one patient. Delayed wound problem did not occur during or after irradiation. Secondary touch-up procedures were performed in 12.3%, the most common being fat graft (8.6%). Average patient satisfaction score was 8.62/10, which was not significantly different from the authors' previous report involving all the TRAM patients (8.50). Conclusion: Radiation therapy did not increase the complication rate significantly. Aesthetic result was affected but was tolerated in most cases. The fear of adjuvant radiation is not a negative factor in selecting immediate breast reconstruction with TRAM flap.

• Radiation Oncology Journal
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• v.30 no.1
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• pp.1-13
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• 2012

In the previous review, the physical aspect of heavy particles, with a focus on the carbon beam was introduced. Particle beam therapy has many potential advantages for cancer treatment without increasing severe side effects in normal tissue, these kinds of radiation have different biologic characteristics and have advantages over using conventional photon beam radiation during treatment. The relative biological effectiveness (RBE) is used for many biological, clinical endpoints among different radiation types and is the only convenient way to transfer the clinical experience in radiotherapy with photons to another type of radiation therapy. However, the RBE varies dependent on the energy of the beam, the fractionation, cell types, oxygenation status, and the biological endpoint studied. Thus this review describes the concerns about RBE related to particle beam to increase interests of the Korean radiation oncologists' society.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.1
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• pp.41-46
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• 2010

Purpose: To analyze differences in the dose uniformity for the computed breast radiation therapy planning with tangential beam between conventional RT using wedge filter and FiF-IMRT using multileaf collimator based onsizes and volumes of breasts. Materials and Methods: Thirty breast cancer patients were classified according to the sizes and volumes of the breasts using Eclipse treatment planning system ($Varian^{TM}$, USA, V8.0). Conformity Index and Homogeneity Index were computed along with Dose Volume Histogram. Results: No differencein CI (${\pm}1.2%$) was observed. However, lower mean HI (1.67%) in FiF-IMRT was observed compared to that of the conventional RT. Statically significant (P<0.01) correlation was identified between the values of ${\Delta}HI$ (%) and physical parameters such as breast volumes and separations. Conclusion: Increase in breast volume and separation improves the dose uniformities in computed radiation therapy planning for FiF-IMRT. Physical dimension of the breast should be considered to optimize the compured radiation therapy planning.

• Radiation Oncology Journal
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• v.10 no.1
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• pp.15-20
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• 1992

A total of 20 patients (male: female=10:10, adult:children=8:12) with brainstem tumors had been received radiation therapy in the Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine between 1980 and 1990. Thirteen of 20 patients were treated with conventional radiation therapy (before 1989, 180~200 cGy per fraction, 5 days a week, total dose 4680~5400 cGy), and seven patients were treated with hyperfractionated radiation therapy (in 1990, 100 cGy per fraction, twice daily 10 fractions a week, total dose 7200 cGy). Median follow up Periods for conventional radiation therapy group and hyperfractionated radiation therapy group were 36 months and 10 months, respectively. Four of 20 Patients had histopathologic diagnosis prior to treatment; 3 cases were low grade astrocytoma and 1 case was high grade astrocytoma. Overall 2-year actuarial survival rate was 30%. The prognosis of patients with a longer duration of symptom and sign was better (60%, vs 12%), and the adult (52%) was better than children (14%). There was no significant difference between the focal (29%) and diffuse (26%) type. The initial clinical response was better in the hyperfractionated radiation therapy group. Because of the relatively small number of Patients and short follow up Period in hyperfractionated radiation therapy group, there was no comparison between two group.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.83-89
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• 1986

High energy radiation therapy using accelerator or radioioisotope teletherapy unit is now one of the most important modality in the field dealing with human malignant tumor. It's successful technology overcomes incurable disease to change into curable disease not only by the improvement of clinical technique but also by the development of radiation physics and biology. The author presented the principles of radiation therapy by means of basic knowledge of medicine. physics and biology, described the various ways to improve the result of radiation therapy, and reviewed recent status of radiotherapy field in Korea.

• Radiation Oncology Journal
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• v.36 no.1
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• pp.45-53
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• 2018

Purpose: Local recurrence is a common failure pattern in adenocarcinoma of the cecum. This study aimed to investigate the potential role of adjuvant radiation therapy on oncologic outcomes of patients with adenocarcinoma of the cecum. Materials and Methods: This retrospective study was carried out at three large tertiary university hospitals. We analyzed the characteristics, prognostic factors, and survival of 162 patients with adenocarcinoma of the cecum that were treated and followed up between 2000 and 2013. All the patients had undergone a right hemicolectomy and received chemotherapy with (n = 48) or without (n = 114) adjuvant radiation therapy. Results: The subjects were 65 females and 97 males with a median age of 56 years (range, 17 to 90 years) at diagnosis. The 5-year local control (LC), disease free survival (DFS), and overall survival (OS) rates were 72.7%, 57.2%, and 62.6% respectively. In a multivariate analysis, age, tumor stage, node stage, and adjuvant radiation therapy were determined to be independent prognostic factors. Age more than 55 years (hazard ratio [HR] = 1.0; 95% confidence interval [CI], 0.06-0.32; p = 0.003), T4 stage (HR = 6.8; 95% CI, 3.07-15.36; p < 0.001), node positive disease (HR = 4.2; 95% CI, 1.94-9.13; p < 0.001), and the absence of adjuvant radiation therapy (HR = 3.0; 95% CI, 1.39-6.46; p = 0.005) had a negative influence on OS. Conclusion: Adjuvant radiation therapy significantly improves DFS and OS in patients with adenocarcinoma of the cecum.

• Progress in Medical Physics
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• v.11 no.1
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• pp.85-90
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• 2000

In radiation therapy, the effects of radiation are decided total dose, total treatment times and number of radiation dose fractions. We considered that total dose, total treatment times and number of radiation dose fractions in intensity modulation radiation therapy(IMRT) infuence tumor cell killing. The goal of three dimensional conformal radiation therapy(3DCRT) in radiation therapy is to conform the partial distribution of the prescribed radiation dose to the precise 3D configuration of the tumor, and at the same time, to minimize the dose to the surrounding normal tissues. To optimize treatment volume of tumor, treatment volume will be same tumor volume. All IMRT compare to conventional treatment plus boost IMRT when total dose irradiated 75 - 90 Gy. Because of biological effect, total dose are decreased 12.5 - l5Gy in all IMRT.