Nuclear Medicine & Radiation Therapy

To compare the set-up uncertainties in breast radiation therapy using two different immobilization methods: vacuum cushion (VC) and standard breast board (BB). The data set comprises of 26 breast cases were divided into two groups based on the type of immobilization used for their radiotherapy treatment, either intensity-modulated radiotherapy (IMRT) or volumetric arc modulated radiotherapy (VMAT). The vacuum cushion group consisted of 14 patients with 143 exposures and the breast board group consisted of 12 patients with 120 exposures. Set-up errors in mediolateral (ML), craniocaudal (CC) and anterioposterior (AP) directions were determined using grey scale matching between the baseline reference and online acquired images by cone beam computed tomography (CBCT) scan. Systematic error (Σ), random error (σ) and mean displacement vector (M) were calculated for both the groups. For Vacuum Cushion group, maximum error observed was 2.75 mm, mean displacement vector was 1.52 mm and mean value of set-up error in ML, CC and AP direction was -0.30 mm, -0.40 mm and 1.60 mm respectively. For Breast Board group, maximum error recorded was 3.87 mm, mean displacement vector was 1.72 mm and mean value of set-up error in ML, CC and AP direction was 0.80 mm, 1.70 mm and 1.50 mm respectively. Setup errors evaluated from the two immobilization methods did not differ significantly (p>0.05). Thus, introduction of the vacuum cushion (VC) into routine breast radiation therapy was seen to be as efficient as BB setup.

Objectives: This prospective study aimed to investigate whether left-sided breast carcinoma patients could maintain deep inspiration (DI) during radiotherapy in order to reduce exposed heart volume.
Methods: Twenty-one patients with left breast carcinoma receiving adjuvant breast radiotherapy were included in this study. Breath hold time was monitored using the cine acquisition mode (CAM) of a linear accelerator during treatment in every fraction. Simulated kV and treatment field images were compared to determine whether the patient could achieve the same “breath holding level” (BHD). Maintenance of BHD during beam on time was referred as “maintenance of intrafraction breath holding level” (BHM), and chest wall displacement during each treatment was measured in order to verify the BHM. Furthermore, the relation between treatment time and patient compliance was studied.
Results: Sixteen patients were treated according to the deep inspiration breath hold (DIBH) protocol while 5 patients, excluded due to noncompliance, received their treatment without breath control. For the patients treated with DIBH protocol, maximum heart doses without breath control and DI phases were 3044 cGy and 1347 cGy, while mean heart doses were 348 cGy and 239 cGy, respectively. Median BHD and BHM displacements were 0.2 cm (0– 0.86 cm) and 0.07 cm (0–0.31 cm), respectively. BHD differences were <0.4 cm in all but 2 patients. Treatment time did not affect patient compliance.
Conclusions: DI phase was successful in reducing heart dose and 76.2% of the patients were eligible for DIBH. Treatment during moderate DI phase can be used for selected left-sided breast carcinoma patients and CAM could monitor safe execution.

The utility of FDG PET-CT in documenting malignant disease has been demonstrated for many disease processes. However, non-malignant causes for FDG PET-CT enhancement exist. Here we present an example of a 12 year-old male diagnosed with Hodgkin’s lymphoma that underwent an FDG PET-CT for evaluation and initial staging. The scan demonstrated disease in the chest and abdomen in addition to focal uptake in the left distal tibia that was considered to represent a focus of disease. Unexpectedly, as the disease was treated, the focal uptake in the leg did not decrease prompting additional CT and conventional radiograph imaging, which found that the lesion was consistent with Non-Ossifying Fibroma (NOF). This case illustrates that FDG PET-CT can identify both malignant disease and benign bone lesions that may masquerade as metastatic disease.

Exposure to natural sources of radiation, especially 222Rn and its short-lived daughter products has become an important issue throughout the world because sustained exposure of humans to indoor radon may cause lung cancer. Therefore, indoor radon concentration levels have been measured inside 8 government hospitals in three main regions (Erbil, Duhok and Sulaymaniya) in Iraqi Kurdistan region during summer season by using CR-39 nuclear track detector. The CR-39 detectors were placed in the all hospitals for three floors (ground, first and second). The highest average radon concentration value and annual effective dose was found to be in the Shaheed Dr. Aso hospital in Sulaymaniya city (52.89 ± 3.52 Bq. m-3 , 1.37 ± 0.09 mSv/y ) respectively and the lowest was found in the Erbil Teaching hospital in Erbil city (30.15 ± 2.85 Bq. m-3 , 0.81 mSv/y) respectively, This depended on the geological formation , type of building material, and the floor level. Therefore, the results showed that the average radon concentration and annual effective dose decreases gradually as the floor level increases The highest and lowest of annual effective dose was found in ground and second floor, respectively. Thus, according to the annual exposure dose data, the workers are safety in most of the hospitals.

The purpose of the study was to analyze the effects of the number of intensity levels on treatment planning outcome of static IMRT method with dynamic IMRT method and also to investigate the integral dose to non-target tissues in both the methods. The IMRT planning was carried out using Eclipse treatment planning system with millennium 120 multileaf collimator (Varian Clinac- 2100 DHX). Five cases each of head and neck, cervix and esophagus cancer were selected for this study. For each case, planning was carried out using both delivery methods. Further for the static IMRT, different numbers of intensity levels ranging from 5 to 20 were studied. The optimization values were kept common for both the techniques and only the leaf motion calculation was varied. The parameters associated with the Dose volume histograms were examined for a more quantitative comparison. The integral doses (0.5 Gy to 30 Gy) of Non-target tissues were also calculated for both techniques. Analyses were performed using a t test to determine difference in any of the parameters examined. For three sites studied, there were no significant changes observed between static IMRT (above 10 intensity levels) and dynamic IMRT method. However there were significant differences observed with 5 intensity level static IMRT plans compared to dynamic IMRT plans. There were no significant changes observed in normal tissue dose values between static IMRT plans and dynamic IMRT plans. The total number of monitor unit was more for dynamic IMRT plans compared to static IMRT plans for all three sites. The integral doses from 0.5 Gy to 30 Gy were analyzed and no significant changes were observed between static IMRT and dynamic IMRT plans

Background: Hidradenitis suppurativa is a chronic follicular occlusive disease in apocrine gland-bearing regions. Frequently refractory to conventional oral and topical treatments, it may require surgical intervention. Objective: To investigate the effectiveness of radiation therapy for refractory hidradenitis suppurativa.
Methods and materials: Five patients with refractory Hurley stage II/III hidradenitis suppurativa were treated with radiation therapy to 13 affected sites. Electron beam radiation to a total dose of 7.5 gray was applied over 3 consecutive days.
Results: The mean age of patients was 45 years; 80% had hidradenitis suppurativa for ≥ 6 years. Three patients had Hurley stage III; 2 had Hurley stage II. All had been treated previously with topical and oral antibiotics and other therapies, including surgery, radiation therapy, Nd:YAG laser therapy, and infliximab. No complete responses were observed, but 53% of the lesions had a partial response. Lesions in the axilla, gluteal, and inguinal areas had response rates of 100%, 67%, and 50%, respectively, compared to 0% for perineal lesions.
Conclusions: Radiation therapy may be a promising treatment for refractory hidradenitis suppurativa. A prospective study is warranted to further evaluate response rates, define optimal dose fractionation schedules, and better understand the risk of long-term toxicity.

Purpose: To quantify inter- and intrafractional variations of tumor position and analyze the relationship between these changes and respiratory motion amplitude, volume changes and tumor location, in frameless stereotactic body radiotherapy (SBRT) of lung tumors.
Materials and methods: Tumor volumes and bony landmarks were contoured manually by a single physician on 174 pre- and under treatment cone-beam computed tomographies (CBCTs) of 17 patients. The interfraction variation of the tumor position was measured by comparing the centroid position of the tumor relative to bony anatomy of each fraction to the pretreatment CBCT scans. The intrafraction variation was measured by comparing the pretreatment tumor location to under treatment CBCTs for every fraction. Respiratory motion was analyzed on planning 4D fan beam CTs for all patients. The change in tumor volume was determined by comparing the contoured tumor volumes on sequential pretreatment CBCTs.
Results: The average interfraction/intrafraction tumor displacementrelative to bony landmark in mm was 0.6 (SD 2.3) /-0.3 (SD 0.7) in mediolateral, -0.7 (SD 3.8) /0.0 (SD 2.1) in anteroposterior, and -0.6 (SD 5.9) /-0.2 (SD 2.3) in craniocaudal direction. Inter-/intrafraction tumor-to-bone variations >3 mm were observed in 60%/14% of scans respectively. On the initial CBCT, the average tumor volume was 9 cm3 (range 1-37 cm3) with a mean volume reduction over the treatment course of 12% (range, +14% to -54%). Patients with a pretreatment motion amplitude > 9 mm (p=0.002), peripheral tumor location (p=0.04), and volume change >12% (p=0.009) had larger interfraction displacement in lateral direction.
Conclusions: Frameless set up is comparable to patient positioning with more elaborate fixation devices. Tumor position variations relative to bony anatomy are an important source of geometric uncertainty providing a rationale for repeated soft tissue-based image guidance, particularly in patients identified in this study to be at higher risk for variations.

Aims and background: Extra-gonadal germ cell tumours (EGCT) are rare tumors, which usually occur in the mediastinum or retroperitoneum; in particular, primary retroperitoneal seminomas account for approximately 2% of all seminomas. We report the case of a 34-year-old male with a locally advanced retroperitonal seminoma.
Methods: The patient underwent debulking surgery followed by cisplatin-based chemotherapy and radiotherapy. Results: No evidence of recurrence was detected during a 30 months follow-up. Although retroperitoneal seminoma is rare, this entity should be considered in the differential diagnosis of a male patient presenting with a mass in the retroperitoneum.
Conclusions: Our case, according to data reported in literature, confirms the curability of retroperitoneal seminoma even in presence of bulky disease, and it represents an example of revised treatment procedure due to patient’s particular condition.

Purpose: It is unknown whether established dose-volume parameters predictive of radiation pneumonitis (RP) are applicable to multiple disease sites. We investigated the factors associated with RP in a heterogeneous population of patients receiving thoracic radiation.
Methods and materials: Ninety-nine patients who received thoracic radiation with helical tomotherapy were included in this retrospective chart review. Correlation studies were performed and significant clinical and dosimetric factors predictive for grade ≥ 3 RP were assessed using Cox multivariate analysis (MVA).
Results: Fifty-two patients developed RP (grade 1-5), the majority having grade 1 toxicity. Five patients experienced grade ≥ 3 RP. Eleven patients developed ≥ 2 RP. The mean time to RP was 3 months. The sole predictor of RP on MVA was a lung volume receiving a maximum of 20 Gy (VS20) < 1600 cc’s (hazard ratio=14.7, p<0.01).
The percentage of lung receiving ≥ 5 Gy or ≥ 20 Gy were not significant predictors for RP. The grade ≥ 3 RP-free survival at 1 year in patients with a VS20 <1600 cc’s versus ≥ 1600 cc’s was 50.0% and 97.1%, respectively (logrank, p<0.01). Results were similar when the RP threshold was lowered to include grade ≥ 2.
Conclusions: A VS20 <1600 cc’s is a significant adverse factor associated with RP; this included cases that were RP grade ≥ 3 and ≥ 2. This is a new dosimetric parameter that can be utilized for treatment planning.