Yongkan Ki

C-REACTIVE PROTEIN LEVELS AND RADIATION-INDUCED MUCOSITIS IN PATIENTS WITH HEAD-AND-NECK CANCER

PURPOSE To evaluate the relationship between C-reactive protein (CRP) levels or the erythrocyte sedimentation rate (ESR) and the grade of acute radiation-induced mucositis in patients with head-and-neck cancer. METHODS AND MATERIALS This study was performed in 40 patients who received intensity-modulated radiation therapy as a radical treatment of primary laryngo-pharyngeal cancer. Serum CRP level and ESR were initially checked on the day of radiotherapy simulation and were measured every week during the irradiation schedule and two times biweekly after radiotherapy. Mucosal reactions were evaluated by radiation oncologists on days of blood sampling. RESULTS The distribution of the most severe mucositis was Grade I mucositis in 10% of the patients, Grade II in 60% of the patients and Grade III in 30% of the patients. Statistical analysis indicated a significant rise in the CRP level (p < 0.001) according to radiation fraction number and grade of mucositis. A change of the mean CRP level was correlated with progression of mean grade of mucositis according to fraction number. The ESR did not show any statistically significant relationship with radiotherapy fraction number and grade of acute mucositis. CONCLUSIONS There was a significant correlation between the presence of acute mucositis and CRP level in this study. The CRP level could be conveniently determined along with evaluation of mucosal reactions during or after radiotherapy to provide further information on radiation-induced mucositis.

Probiotics for Rectal Volume Variation During Radiation Therapy for Prostate Cancer

PURPOSE To investigate the effect of the probiotic Lactobacillus acidophilus on the percentage volume change of the rectum (PVCR), a crucial factor of prostate movement. METHODS AND MATERIALS Prostate cancer patients managed with tomotherapy as a radical treatment were enrolled in the study to take a probiotic capsule containing 1.0×10(8) colony-forming units of L acidophilus or a placebo capsule twice daily. Radiation therapy was performed at a dose of 78 Gy in 39 fractions. The PVCR, defined as the difference in rectal volume between the planning computed tomographic (CT) and daily megavoltage CT images, was analyzed. RESULTS Forty patients were randomized into 2 groups. The L acidophilus group showed significantly lower median rectal volume and median PVCR values than the placebo group. L acidophilus showed a significant reduction effect on the PVCR (P<.001). However, the radiation therapy fraction number did not significantly influence the PVCR. CONCLUSIONS L acidophilus was useful in reducing the PVCR, which is the most important determining factor of prostate position, during radiation therapy for prostate cancer.

The Effect of Probiotics for Preventing Radiation-Induced Morphological Changes in Intestinal Mucosa of Rats

Radiation therapy is an important treatment modality for abdominal or pelvic cancer, but there is a common and serious complication such as radiation-induced enteritis. Probiotics is reported to have positive effects against radiation-induced enteropathy. In this study, morphological changes of bowel mucosa were analyzed in rats to presume the effect of probiotics on radiation-induced enteritis and its correlation with radiation dose. A total of 48 adult male Sprague-Dawley rats were randomly assigned to two groups and received a solution containing 1.0×108 colony-forming units of Lactiobacillus acidophilus or water once daily for 10 days. Each of two groups was divided into three subgroups and abdomino-pelvic area of each subgroup was irradiated with 10, 15, and 20 Gy, respectively on the seventh day of feeding the solutions. All rats were sacrificed 3 days after irradiation and the mucosal thickness and villus height of jejunum, ileum and colon were measured. The morphological parameters of the small intestine represented significant differences between two solution groups irradiated 10 or 15 Gy, except for villus height of jejunum in 15 Gy-subgroup (P=0.065). There was no significant morphometric difference between two groups irradiated with 20 Gy of radiation. Probiotics appear to be effective for the morphological shortening of small intestinal mucosa damaged by radiation less than or equal to 15 Gy. Graphical Abstract

Pretreatment maximum standardized uptake value of (18) F-fluorodeoxyglucose positron emission tomography as a predictor of distant metastasis in adenoid cystic carcinoma of the head and neck.

The purpose of this study was to determine whether the maximum standardized uptake value (SUVmax) of the primary tumor on pretreatment 18F‐fluorodeoxyglucose positron emission tomography (18F‐FDG PET) has prognostic significance in patients with adenoid cystic carcinoma (ACC) of the head and neck.

Fractionated Wide-Field Radiation Therapy Followed by Fractionated Local-Field Irradiation for Treating Widespread Painful Bone Metastasis

PURPOSE Wide-field radiation therapy (WFRT) is an effective treatment for widespread bone metastasis. We evaluated local-field irradiation (LFI) after fractionated WFRT (f-WFRT) for treating the patients with multiple painful bone lesions. METHODS AND MATERIALS From 1998 to 2007, 32 patients with multiple bone metastases were treated with fractionated LFI (f-LFI) after f-WFRT. All patients initially received 15 Gy in 5 fractions to a wide field, followed by LFI (9-15 Gy in 3 Gy fractions). Response was assessed by evaluating the degree of pain relief using a visual analog scale before radiotherapy, after f-WFRT, and after f-LFI. RESULTS Fractionated LFI following f-WFRT yielded an overall relief rate of 93.8% and a complete relief rate of 43.8%. The rate of the appearance of new disease was 6.3% for the patients with complete relief, 20.5% for the patients with a partial relief, and 50% for the patients with no relief. CONCLUSION Fractionated LFI after f-WFRT is a well-tolerated and effective treatment for multiple metastatic bone disease.

Effect of Coenzyme Q10 on Radiation Nephropathy in Rats

The kidney is one of the most radiosensitive organs in the abdominal cavity and is the dose-limiting structure in cancer patients receiving abdominal or total body irradiation. In the present study, the effect of coenzyme Q10 (CoQ10) on radiation nephropathy was evaluated in rats. A total of 72 rats were equally randomized into 4 groups: Control, CoQ10, irradiation with 10 Gy (RT) + placebo, or RT + CoQ10. The 2 RT groups received single 10 Gy of abdominal irradiation. The 2 CoQ10 groups were supplemented daily with 1 mL of soybean oil containing 10 mg/kg of CoQ10. The RT + placebo and control groups received same dose of soybean oil. After 24 weeks, laboratory and histopathologic findings were compared. The 2 RT groups showed significant increases in blood urea nitrogen (BUN) and creatinine levels and significant pathologic changes such as glomerulosclerosis and tubulointerstitial fibrosis. CoQ10 supplementation resulted in significant reductions of BUN and creatinine levels compared with the RT + placebo group (P < 0.001 and P = 0.038, respectively). CoQ10 treatment significantly attenuated glomerular and tubular changes of irradiated kidney in semiquantitative analysis (P < 0.001 for both). Administration of CoQ10 can alleviate the radiation-induced nephropathy.

Adjuvant external beam radiation and brachytherapy for vaginal resection margin positive cervical cancer

Purpose To evaluate the treatment outcomes of adjuvant external beam radiation therapy (EBRT) and vaginal brachytherapy (VB) following radical hysterectomy in cervical cancer patients with involved vaginal resection margin (VRM). Materials and Methods We retrospectively reviewed the medical records of 21 patients treated with postoperative EBRT and VB for positive VRM FIGO stage IB–IIA cervical cancer between 2003 and 2015. Concurrent platinum-based chemotherapy was administered to all patients. Results The median whole pelvis EBRT dose was 50.4 Gy (range, 45 to 50.4 Gy). In the VB, the median dose per fraction, number of fractions, and total dose delivered were: 4 Gy (range, 3.0 to 4.0 Gy), 4 fractions (range, 3 to 5 fractions), and 16 Gy (range, 12 to 20 Gy), respectively. At a median follow-up of 46 months (range, 9 to 122 months), local recurrence was observed in 2 patients, and distant metastasis was present in 7 patients. All patients with local recurrence subsequently developed distant metastases. The 5-year local control, disease-free survival, and overall survival rates were 89.1%, 65.9%, and 62.9%, respectively. Of the 21 patients, 7 patients (33.3%) reported grade 2 acute toxicity; however, there were no grade 3 or higher acute adverse events. Grade 1–2 late toxicities were observed in 8 patients. Late grade 3 urinary toxicity was reported in 1 patient. conclusions Adjuvant EBRT and VB showed excellent local control and low toxicity in cervical cancer patients with positive VRM. Although limited by its retrospective nature, the findings from our study provide evidence supporting the use of additional VB in pathologically involved VRM.

Generation of polychromatic projection for dedicated breast computed tomography simulation using anthropomorphic numerical phantom

Numerical simulations are fundamental to the development of medical imaging systems because they can save time and effort in research and development. In this study, we developed a method of creating the virtual projection images that are necessary to study dedicated breast computed tomography (BCT) systems. Anthropomorphic software breast phantoms of the conventional compression type were synthesized and redesigned to meet the requirements of dedicated BCT systems. The internal structure of the breast was randomly constructed to develop the proposed phantom, enabling the internal structure of a naturally distributed real breast to be simulated. When using the existing monochromatic photon incidence assumption for projection-image generation, it is not possible to simulate various artifacts caused by the X-ray spectrum, such as the beam hardening effect. Consequently, the system performance could be overestimated. Therefore, we considered the polychromatic spectrum in the projection image generation process and verified the results. The proposed method is expected to be useful for the development and optimization of BCT systems.

Utility of the Equivalent Depth Concept for in-vivo Dosimetry With No Build-up on the Skin Using Glass Rod Dosimeter (GRD) : Preliminary Results

Therapeutic dose verification with in-vivo dosimetry is important in modern radiotherapy because of its high complexity and high precision. The conventional dosimeters, thermoluminescent dosimeter (TLD) or dosimetric films for examples, has been widely used. However, they require a great care because of their complicated calibration and readout procedures. Furthermore, use of build-up involves change of delivered dose distribution. We tried to use a radiophotoluminescent glass rod dosimeter (GRD) system with no build-up on the skin. The equivalent depth concept for each effective field size and each incident beam angle was introduced to perform effective in-vivo dosimetry on the skin. As a preliminary result, we successfully obtained a equivalent depth table using 20 GRDs. We performed in-vivo dosimetry to verify the usefulness of this table in three patients, and found that there are deviations less than 5.0%. Finally, we found the possibility to perform effective in-vivo dosimetry with no build-up on the skin. The obtaining of a more precise equivalent depth table and more clinical verification will be our further works.

SU‐E‐J‐179: The Accurate Electron Density Image Containing Metal Prosthesises Through the Hybrid Sinogram for Tomotherapy: A Phantom Study

Purpose: To obtain the hybrid CT images, which have both the high contrast of kV‐CT and very low metal artifact of MV‐CT, for tomotherapy patients with metal prosthesisesMethods: We used a standard cheese phantom containing four metal inserts (copper, silver, tin, tungsten) to acquire a kV‐sinogram by a CT simulator and a MV‐CT image by Tomotherapy. The MV‐sinogram was acquired by the forward projection of the MV‐CT image using the geometry of kV‐CT system. Both sinograms were normalized with their total length of x‐ray attenuation and then were converted to the mean electron densities using corresponding calibration curves. The metal data in the MV‐sinogram were segmented using a given density threshold and transplanted to the kV‐sinogram row by row to acquire the normalized hybrid sinogram. The misalignment between metal data of two sinograms was corrected by mutual information technique. The hybrid CT image was finally obtained through de‐normalization and back‐projection procedures. For the experimental verification, film measurements were performed and analyzed using three head and neck treatment plans. Results: We found that the hybrid CT image of the cheese phantom containing four metal inserts has similar contrast and very low metal artifact compared to the kV‐CT image. Moreover, the metal densities on the hybrid CT‐image were accurate with the mean deviation of 3.3%. As the Result of film measurements, the average gamma pass rate of kV‐CT plan and hybrid‐CT plan were 93.7% and 96.5% with the criteria of 2%/2mm, and 67.1% and 81.4% with the criteria of 1%/1mm. Conclusions: This work indicated that the hybrid CT image can improve the accuracy of tomotherapy treatment plan with metal prosthesises without additional imaging dose. Our further study is to acquire and evaluate hybrid CT images from clinical kV‐sinograms and MV‐CT images.