Therapeutic Effects of Low-Level Laser Therapy on Pain and Disability of Patients with Failed Back Surgery Syndrome.

Purpose: This study intended to evaluate the effects of Low-Level Laser Therapy (LLLT) on Failed Back Surgery Syndrome (FBSS). FBSS refers to symptoms and disabilities which remain or occur after lumbar spinal surgery. Prevalent treatments for FBSS are based mostly on conservative management while LLLT has gained significant interest in the treatment of a wide variety of musculoskeletal disorders. Methods: In the present study, the authors included 50 individuals with FBSS. Target points were determined by an ultrasonic study including bilateral L2-L3 through L5-S1 facet joints, sacroiliac joints, and the region immediately above bilateral supra crestal iliac bones representing cluneal nerves. LLLT was performed three times a week for 3 weeks. A near-infrared laser (wavelength 808 nm, power 500 mw) was used in continuous mode for laser therapy sessions. The Numeric Rating Scale (NRS) and Oswestry Disability Index (ODI) were registered before treatment and after last treatment session, 1 month and 6 months later, respectively. Results: NRS and ODI were significantly improved after treatment, as well as therapeutic effects, after 1 month and 6 months were also evident and comparison of the NRS and ODI showed significant difference. Conclusion: LLLT has a positive impact on pain and disability in patients with FBSS.

Comparison of normal tissue doses in deep inspiration breath-hold and free breathing methods for radiotherapy of left-sided breast cancer using 4D-XCAT digital phantom.

Purpose: To evaluate normal lung and heart tissue doses for treatment of left-sided breast cancer in deep inspiration breath-hold (DIBH) and free breathing (FB) as a function of breast size and diaphragm displacement using 4D-XCAT digital phantom in a simulation study. Materials and Methods: 4D-XCAT digital phantom was used to create 36 left-sided breast cancer digital phantom datasets with different breast height (BH) of 40, 50, and 60 mm, breast length (BL) of 16, 17, and 18 mm, and diaphragm excursion of 20, 25, 30, and 35 mm. For each dataset, DIBH and FB treatment plans were prepared using planning computerized radiotherapy-three dimensional (PCRT-3D) treatment planning system (TPS) with superposition computational algorithm. Dose differences in DIBH and FB plans were assessed in terms of mean lung dose (MLD), the lung volume receiving ≤20 Gy (V20), normal tissue complication probability (NTCP) of the lung, mean heart dose (MHD), and the heart volume receiving ≤30 (V30). Results: DIBH reduced mean dose and V20 and NTCP of the lung in all cases, by up to 4.37 Gy, 7.62%, and 18.95%. Mean dose and V30 of the heart were also significantly reduced by 5.02 Gy and 8.23%. Conclusions: The use of DIBH for left-sided breast cancer radiotherapy offers excellent possibilities for sparing critical normal tissue without compromising radiation dose to the target.

Evaluating the effects of metal artifacts on dose distribution of the pelvic region.

AIM OF THE STUDY: Some cancerous patients have hip prosthesis of metal elements when they undergo radiation therapy. Metal implants are a cause of metal artifacts in computed tomography (CT) images due to their higher density compared to normal tissues. The aim of this study is to evaluate the quantitative effects of metal artifacts on dose distribution of the pelvic region. MATERIALS AND METHODS: Seven patients with metal implants in the pelvic region were scanned and CT images were exported to the Monaco treatment planning system. Based on the diagnosis of each patient, three-dimensional plans were implemented on CT images and dose distributions were extracted. At the next step, metal artifacts were contoured and electron densities of these new structures were modified to the extent of soft tissue. Finally, dose distributions and the differences were investigated by VeriSoft software. RESULTS: The results of this study showed that if the electron density to metal artifacts is not assigned properly, it will increase the calculated monitor units (MUs) by almost 3.78 MUs/fraction which will significantly affect total dose distribution of treatment. CONCLUSION: For the precise implementation of the treatment and in order to minimize the systematic errors related to the calculated MUs, necessary corrections on the electron density of metal artifacts should be considered before the treatment planning. The issue will be more critical in advanced treatment modalities where dose escalation is needed.

Analysis of the caregiver effective dose during I-131 therapy of thyroid.

AIMS: The main objective of the present research is to analyze the caregiver effective dose during I-131 therapy of thyroid in some different situations using MCNP4C Monte Carlo code. PATIENTS AND METHODS: Two separate whole body Medical Internal Radiation Dosimetry (MIRD) phantoms have been defined simultaneously in a single Monte Carlo N-Particle (MCNP) input file as the patient and the caregiver. Two different groups of irradiation situations have been assumed for the caregiver related to the patient, (1) both the patient and the caregiver are standing and (2) the patient is lying in the bed while the caregiver is standing beside the patient. RESULTS: The results show that the caregiver effective dose is highly dependent on the position of the caregiver related to the patient. When the patient is lying on the bed and the caregiver is standing beside the patient near the head of the patient, the effective dose of caregiver will be the maximum value. CONCLUSIONS: Although the maximum effective dose (0.2 mSv) is smaller than the allowed value for caregivers (5 mSv for each treatment), the final results of this research indicate the importance of caregiver position in close contact with the patient.