• Journal of radiological science and technology
• /
• v.43 no.6
• /
• pp.469-473
• /
• 2020

Breast cancer is growing rapidly year by year and has the highest incidence since 2001. As a result, the interest in mammography for early detection of breast cancer is increasing. However, mammography is accompanied by radiation exposure and therefore it is necessary to reduce exposure dose through appropriate test conditions. The significance of this study is that breast dose studies, which were limited to ordinary women, were applied to breast implant patient. Using MCNP simulation, the phantom with prosthesis inserted was developed to compare dose by tube voltage by pressure thickness. In addition phantom without prostheses has higher dose than phantom with prostheses. If these results were used as basic data, it would be possible to recommend test condition guideline only for breast implant patients.

• Progress in Medical Physics
• /
• v.26 no.4
• /
• pp.208-214
• /
• 2015

The aim of this study is to investigate the effect of low magnetic field on dose distribution in the partial-breast irradiation (PBI). Eleven patients with an invasive early-stage breast carcinoma were treated prospectively with PBI using 38.5 Gy delivered in 10 fractions using the $ViewRay^{(R)}$ system. For each of the treatment plans, dose distribution was calculated with magnetic field and without magnetic field, and the difference between dose and volume for each organ were evaluated. For planning target volume (PTV), the analysis included the point minimum ($D_{min}$), maximum, mean dose ($D_{mean}$) and volume receiving at least 90% ($V_{90%}$), 95% ($V_{95%}$) and 107% ($V_{107%}$) of the prescribed dose, respectively. For organs at risk (OARs), the ipsilateral lung was analyzed with $D_{mean}$ and the volume receiving 20 Gy ($V_{20\;Gy}$), and the contralateral lung was analyzed with only $D_{mean}$. The heart was analyzed with $D_{mean}$, $D_{max}$, and $V_{20\;Gy}$, and both inner and outer shells were analyzed with the point $D_{min}$, $D_{max}$ and $D_{mean}$, respectively. For PTV, the effect of low magnetic field on dose distribution showed a difference of up to 2% for volume change and 4 Gy for dose. In OARs analysis, the significant effect of the magnetic field was not observed. Despite small deviation values, the average difference of mean dose values showed significant difference (p<0.001), but there was no difference of point minimum dose values in both sehll structures. The largest deviation for the average difference of $D_{max}$ in the outer shell structure was $5.0{\pm}10.5Gy$ (p=0.148). The effect of low magnetic field of 0.35 T on dose deposition by a Co-60 beam was not significantly observed within the body for PBI IMRT plans. The dose deposition was only appreciable outside the body, where a dose build-up due to contaminated electrons generated in the treatment head and scattered electrons formed near the body surface.

• Proceedings of the Korea Contents Association Conference
• /
• 2015.05a
• /
• pp.187-188
• /
• 2015

유방촬영은 날로 증가추세에 있으며 압박을통해 영상을 얻는 것이 화질을 향상시키고 피폭선량을 줄이는데 필수적이다. 그러나 압박대 자체의 두께로 인해 산란선과 피폭선량을 증가시킬 수 있으므로 압박대 재질에 대한 고찰이 필요하다. 현재 임상에서 쓰이고 있는 재질은 폴리카보네이트이며 플라스틱 계열이다. 환자의 피폭선량을 줄이기위해 노력한다면 이보다 더 좋은 재질에 대해 고려해볼 필요가 있기에 본 연구에서는 플라스틱 계열 물질 중 비결정 플라스틱에 대한 방사선투과성에 대해 비교해 보고자 한다.

• Journal of the Korean Society of Radiology
• /
• v.12 no.3
• /
• pp.373-379
• /
• 2018

The purpose of this study was to investigate quantitative data on the difference in breast entrance surface dose with changes in focus-film distance, patient posture (anteroposterior-posteroanterior), thoracic wall thickness, rib bone thickness, lung tissue thickness, tube voltage, and high-voltage rectification method in Whole Spine Scanography, which is necessary for the treatment of scoliosis patients. Given a tube voltage of 90 kVp, kerma of 0.1 mGy, focus-film distance of 260 cm, tube voltage ripple rate of 0, filter thickness of 3.5 mm, and thickness of patient's thoracic wall of 120 mm as an X-ray exposure condition, from the simulation results using the Simulation of X-ray Spectra program to confirm the reduction effect of breast entrance surface dose according to the patient's posture (AP and PA), there was a dose reduction effect in aluminum filter thickness of 2.6 times at 3.5 mm, 25.7 times the thoracic wall thickness at 120 mm, 1.43 times higher tube voltage, and 0 to 1.14 times the tube voltage ripple rate. The total dose reduction effect was about 109 times. In order to confirm the dose reduction effect of RANDO phantom posture (AP and PA), from the results of the measurements taken under the conditions that the focus-film distance was 260 cm, the tube voltage was 90 kVp, the tube current was 270 mA, the exposure time was 0.31 sec, and the tube voltage ripple rate of X-ray generators was 0, the entrance surface dose reduction effect of the breast in the PA position was found to be 20.56 times lower than that of the AP position.

• Journal of the Korean Society of Radiology
• /
• v.7 no.1
• /
• pp.51-55
• /
• 2013

When the X-ray energy is high, the X-ray penetrates the object and decrease the contrast of imaging, and when the X-ray energy is low, the X-ray increases the contrast of imaging but it is to be absorbed into the object, which in the long run increases patient's radiation exposure level. Therefore, appropriate X-ray energy is an essential element affecting the imaging quality and radiation exposure level. This study simulated the energy spectrums according to the target materials of mammography, and compared qualities of phantom imaging for the management of radiolographic quality and patient's radiation exposure level with the introduction of the mammography that employs diversified radiation quality by using new anode materials.

• The Journal of Korean Society for Radiation Therapy
• /
• v.18 no.2
• /
• pp.113-117
• /
• 2006

Purpose: Post-mastectomy radiotherapy (PMR) is known to decrease loco-regional recurrence. Adequate skin and dermal dose are achieved by adding bolus. The more difficult clinical issue is determining the necessary number of bolus treatment, given the limits of normal skin tolerance. The aim of this study is to evaluate the necessary number of bolus treatment after PMR in patients with breast cancer. Materials and Methods: Four female breast cancer patients were included in the study. The median age was 53 years(range, $38{\sim}74$), tumor were left sided in 2 patients and right sided in 2patients. All patients were treated with postoperative radiotherapy after MRM. Radiotherapy was delivered to the chest wall (C.W) and supraclavicular lymph nodes (SCL) using 4 MV X-ray. The total dose was 50 Gy, in 2 Gy fractions (with 5 times a week). CT was peformed for treatment planning, treatment planning was peformed using $ADAC-Pinnacles^3$ (Phillips, USA) for all patients without and with bolus. Bolus treatment plans were generated using image tool (0.5 cm of thickness and 6 cm of width). Dose distribution was analyzed and the increased skin dose rate in the build-up region was computed and the skin dose using TLD-100 chips (Harshaw, USA) was measured. Results: No significant difference was found in dose distribution without and with bolus; C.W coverage was $95{\sim}100%$ of the prescribed dose in both. But, there was remarkable difference in the skin dose to the scar. The skin dose to the scar without and with bolus were $100{\sim}105%\;and\;50{\sim}75%$. The increased skin dose rates in the build-up region for Pt. 1, Pt. 2. Pt. 3 and Pt. 4 were 23.3%, 35.6%, 34.9%, and 41.7%. The results of measured skin dose using TLD-100 chips in the cases without and with bolus were 209.3 cGy and 161.1 cGy, 200 cGy and 150.2 cGy, 211.4 cGy and 160.5 cGy, 198.6 cGy and 155.5 cGy for Pt. 1, Pt. 2, Pt. 3, and Pt. 4. Conclusion: It was concludes through this analysis that the adequate number of bolus treatments is 50-60% of the treatment program. Further, clinical trial is needed to evaluate the benefit and toxicity associated with the use of bolus in PMR.

• Radiation Oncology Journal
• /
• v.27 no.1
• /
• pp.35-41
• /
• 2009

Purpose: This study was designed to determine the optimum radiotherapy technique for internal mammary node (IMN) irradiation after breast-conserving surgery. Materials and Methods: We selected ten cases of early stage partial mastectomy for plan comparison. Five of the patients were treated to the right-side breast and the rest of the patients were treated to the left-side breast. For each case, four different treatment plans were made to irradiate the entire breast, IMNs and supraclavicular lymph nodes (SCLs). The four planning techniques include a standard tangential field (STF), wide tangential field (WTF), partially wide tangential field (PWT) and a photon-electron mixed field (PEM). We prescribed a dose of 50.4 Gy to the SCL field at a 3 cm depth and isocenter of the breast field. Results: The dose distribution showed clear characteristics depending on the technique used. All of the techniques covered the breast tissue well. IMN coverage was also good, except for the STF, which was not intended to cover IMNs. For the cases of the left-side breasts, the volume of the heart that received more than 30 Gy was larger (in order) for the WTF, PWT, PEM and STF. For radiation pneumonitis normal tissue complication probability (NTCP), the PWT showed the best results followed by the STF. Conclusion: Despite the variety of patient body shapes, the PWT technique showed the best results for coverage of IMNs and for reducing the lung and heart dose.

• The Journal of Korean Society for Radiation Therapy
• /
• v.26 no.2
• /
• pp.329-336
• /
• 2014

Purpose : To evaluate the dose on a contralateral breast and the usefulness of shielding according to the distance between the contralateral breast and the side of the beam by breast size when patients who got breast implant receive radiation therapy. Materials and Methods : We equipped 200 cc, 300 cc, 400 cc, and 500 cc breast model on the human phantom (Rando-phantom), acquired CT images (philips 16channel, Netherlands) and established the radiation treatment plan, 180 cGy per day on the left breast (EclipseTM ver10.0.42, Varian Medical Systems, USA) by size. We set up each points, A, B, C, and D on the right(contralateral) breast model for measurement by size and by the distance from the beam and attached MOSFET at each points. The 6 MV, 10 MV and 15 MV X-ray were irradiated to the left(target) breast model and we measured exposure dose of contralateral breast model using MOSFET. Also, at the same condition, we acquired the dose value after shielding using only Pb 2 mm and bolus 3 mm under the Pb 2 mm together. Results : As the breast model is bigger from 200 cc to 500 cc, The surface of the contralateral breast is closer to the beam. As a result, from 200 cc to 500 cc, on 180 cGy basis, the measurement value of the scattered ray inclined by 3.22 ~ 4.17% at A point, 4.06 ~ 6.22% at B point, 0.4~0.5% at C point, and was under 0.4% at D point. As the X-ray energy is higher, from 6 MV to 15 MV, on 180 cGy basis, the measurement value of the scattered ray inclined by 4.06~5% at A point, 2.85~4.94% at B point, 0.74~1.65% at C point, and was under 0.4% at D point. As using Pb 2 mm for shield, scattered ray declined by average 9.74% at A and B point, 2.8% at C point, and is under 1% at D point. As using Pb 2 mm and bolus together for shield, scattered ray declined by average 9.76% at A and B point, 2.2% at C point, and is under 1% at D point. Conclusion : Commonly, in case of patients who got breast implant, there is a distance difference by breast size between the contralateral breast and the side of beam. As the distance is closer to the beam, the scattered ray inclined. At the same size of the breast, as the X-ray energy is higher, the exposure dose by scattered ray tends to incline. As a result, as low as possible energy wihtin the plan dose is good for reducing the exposure dose.

• Journal of the Korean Society of Radiology
• /
• v.14 no.4
• /
• pp.345-351
• /
• 2020

In this study, a dose assessment was conducted on the exposure dose of thyroid, breast and sexual gland using a personal dosimeter in multiple CT examinations currently being conducted in health examinations. The dose assessment was measured by attaching TLD and EPD to the locations of the thyroid, breast and sexual gland during CT examinations of Brain, Brain + C-S, Brain + Low lung, Brain + L-S among CT items. The generated dose of equipment, CTDI_vol and DLP, was measured. The study found that effective doses were rated 41.7% higher for thyroid TLD in Brain + C-S CT examinations than for the general public, 156% higher for EPD, 10% for breast EPD in Brain + Low Lung CT examinations, 124.4% higher for reproductive TLD and 339.8% higher for Brain + L-S CT examinations. The CTDI_vol and DLP analysis results showed that C-S CTDI_vol values were higher than the diagnostic reference levels at 0.6%, Low Lung CTDI_vol values at 5.7%, DLP values at 11.8% and L-S CTDIvol values at 1.2%. In order to reduce the exposure dose of patients, indiscriminate examination is reduced and dose limit setting is needed in health examination.

• Journal of the Korean Society of Radiology
• /
• v.16 no.7
• /
• pp.851-856
• /
• 2022

The purpose of this study is to confirm the effect of reducing the surface dose around the radiation field in breast cancer radiotherapy using the Field-in-Field (FIF) technique. X-ray was exposed from a linear accelerator (Linac) was used for irradiation, and the surface dose was measured with a glass dosimeter. The source-to-surface distance (SSD) was 90 cm, the field size is 10 × 10 cm², and the X-ray energy was 6 MV and 10 MV, respectively. The surface dose of the FIF was compared with the dose measured in the physical wedge (PW) and dynamic wedge (DW). Wedge angles of 15° and 30° were used in the PW and DW, respectively. Surface dose was measured at 1 cm, 3 cm, and 5 cm from the center of the field size, respectively. According to the results, FIF showed lower surface dose compared to PW and DW regardless of the energy of the X-ray beam, wedge angle, and dose measurement point. Since FIF could reduce the radiation dose in periphery of the field size in breast cancer treatment, it is expected to be able to reduce the secondary damage caused by the radiation beam as well as to obtain a uniform dose distribution on the target.