Evaluation of the hybrid-dynamic conformal arc therapy technique for radiotherapy of lung cancer

PURPOSE: A hybrid-dynamic conformal arc therapy (HDCAT) technique consisting of a single half-rotated dynamic conformal arc beam and static field-in-field beams in two directions was designed and evaluated in terms of dosimetric benefits for radiotherapy of lung cancer. MATERIALS AND METHODS: This planning study was performed in 20 lung cancer cases treated with the VERO system (BrainLAB AG, Feldkirchen, Germany). Dosimetric parameters of HDCAT plans were compared with those of three-dimensional conformal radiotherapy (3D-CRT) plans in terms of target volume coverage, dose conformity, and sparing of organs at risk. RESULTS: HDCAT showed better dose conformity compared with 3D-CRT (conformity index: 0.74 ± 0.06 vs. 0.62 ± 0.06, p < 0.001). HDCAT significantly reduced the lung volume receiving more than 20 Gy (V20: 21.4% ± 8.2% vs. 24.5% ± 8.8%, p < 0.001; V30: 14.2% ± 6.1% vs. 15.1% ± 6.4%, p = 0.02; V40: 8.8% ± 3.9% vs. 10.3% ± 4.5%, p < 0.001; and V50: 5.7% ± 2.7% vs. 7.1% ± 3.2%, p < 0.001), V40 and V50 of the heart (V40: 5.2 ± 3.9 Gy vs. 7.6 ± 5.5 Gy, p < 0.001; V50: 1.8 ± 1.6 Gy vs. 3.1 ± 2.8 Gy, p = 0.001), and the maximum spinal cord dose (34.8 ± 9.4 Gy vs. 42.5 ± 7.8 Gy, p < 0.001) compared with 3D-CRT. CONCLUSIONS: HDCAT could achieve highly conformal target coverage and reduce the doses to critical organs such as the lung, heart, and spinal cord compared to 3D-CRT for the treatment of lung cancer patients.

Development of an experimental model for radiation-induced inhibition of cranial bone regeneration / 대한악안면성형재건외과학회지

BACKGROUND: Radiation therapy is widely employed in the treatment of head and neck cancer. Adverse effects of therapeutic irradiation include delayed bone healing after dental extraction or impaired bone regeneration at the irradiated bony defect. Development of a reliable experimental model may be beneficial to study tissue regeneration in the irradiated field. The current study aimed to develop a relevant animal model of post-radiation cranial bone defect. METHODS: A lead shielding block was designed for selective external irradiation of the mouse calvaria. Critical-size calvarial defect was created 2 weeks after the irradiation. The defect was filled with a collagen scaffold, with or without incorporation of bone morphogenetic protein 2 (BMP-2) (1 μg/ml). The non-irradiated mice treated with or without BMP-2-included scaffold served as control. Four weeks after the surgery, the specimens were harvested and the degree of bone formation was evaluated by histological and radiographical examinations. RESULTS: BMP-2-treated scaffold yielded significant bone regeneration in the mice calvarial defects. However, a single fraction of external irradiation was observed to eliminate the bone regeneration capacity of the BMP-2-incorporated scaffold without influencing the survival of the animals. CONCLUSION: The current study established an efficient model for post-radiation cranial bone regeneration and can be applied for evaluating the robust bone formation system using various chemokines or agents in unfavorable, demanding radiation-related bone defect models.

Reactive Arthritis in a Patient with Chlamydia trachomatis Infection / 대한정형외과학회잡지

The authors report a case of reactive arthritis that was caused by sexual contact as below example. A 36-year-old male visited our center due to sudden pain in wrist joint, the 3rd finger, knee joint, and achilles tendon. There were no specific abnormalities for the immunoserologic tests and magnetic resonance imaging; however, we found a positive test result for the polymerase chain reaction test of urine that identified Chlamydia trachomatis. Through considering the patient's medical history and various examinations, we considered the possibility of reactive arthritis, to the exclusion of alternate diagnosis. According to the our diagnosis, the patient was treated with antibiotics and nonsteroidal anti-inflammatory drugs and we found that the patient was getting better. Therefore the authors think that we have to contemplate the possibility of reactive arthritis and treat appropriately in patients with similar symptoms.

Posterior Thigh Compartment Syndrome as a Result of Pseudoaneurysm of the Popliteal Artery in the Distal Femoral Fracture: A Case Report

Compartment syndrome of the thigh is a rare condition and usually occurs in the anterior compartment. It is frequently caused by muscle injury, femur fracture, muscle overuse and vessel injury, but there have been few reports about posterior thigh compartment syndrome caused by pseudoaneurysm of the popliteal artery after fixation of distal femoral fracture with the retrograde intramedullary nail. We report a case of posterior thigh compartment syndrome caused by pseudoaneurysm of the popliteal artery, and report the clinical progression and result of our case.

Impact of Computed Tomography Slice Thickness on Intensity Modulated Radiation Therapy Plan / 대한방사선종양학회지

PURPOSE: This study was to search the optimal slice thickness of computed tomography (CT) in an intensity modulated radiation therapy plan through changing the slice thickness and comparing the change of the calculated absorbed dose with measured absorbed dose. MATERIALS AND METHODS: An intensity modulated radiation therapy plan for a head and neck cancer patient was done, first of all. Then CT with various ranges of slice thickness (0.125~1.0 cm) for a head and neck anthropomorphic phantom was done and the images were reconstructed. The plan parameters obtained from the plan of the head and neck cancer patient was applied into the reconstructed images of the phantom and then absorbed doses were calculated. Films were inserted into the phantom, and irradiated with 6 MV X-ray with the same beam data obtained from the head and neck cancer patient. Films were then scanned and isodoses were measured with the use of film measurement software and were compared with the calculated isodeses. RESULTS: As the slice thickness of CT decreased, the volume of the phantom and the maximum absorbed dose increased. As the slice thickness of CT changed from 0.125 to 1.0 cm, the maximum absorbed dose changed ~5%. The difference between the measured and calculated volume of the phantom was small (3.7~3.8%) when the slice thickness of CT was 0.25 cm or less. The difference between the measured and calculated dose was small (0.35~1.40%) when the slice thickness of CT was 0.25 cm or less. CONCLUSION: Because the difference between the measured and calculated dose in a head and neck phantom was small and the difference between the measured and calculated volume was small when the slice thickness of CT was 0.25 cm or less, we suggest that the slice thickness of CT should be 0.25 cm or less for an optimal intensity modulated radiation therapy plan.