Hypofractionated Hybrid Radiotherapy Techniques for Synchronous Bilateral Breast Cancer.

OBJECTIVE: This study intends at a dosimetric comparison of four different hybrid plans which is a combination of different radiation therapy techniques, for synchronous bilateral breast cancer (SBBC) irradiation using a hypofractionated dose regimen. METHODS: Four different hybrid techniques: 3DCRT+IMRT, 3DCRT+VMAT, IMRT+VMAT, and VMAT+IMRT were planned using computed tomography (CT) images of fifteen SBBC patients.  All hybrid plans were generated using a hypofractionated dose prescription of 40.5 Gy in 15 fractions. 70% of the dose was planned with a base-dose component and the remaining 30% of the dose was planned with a hybrid component. The plans were evaluated based on the PTV and organs at risk (OARs) dosimetric parameter results and computed a plan quality score for each plan. RESULTS: The results for PTV parameters have shown that the 3DCRT+VMAT and 3DCRT+IMRT plans were better than other plans. The 3DCRT±IMRT plan was provided better results for OARs, while IMRT±VMAT and VMAT+IMRT plans were increased the low dose volumes to the heart and lungs. The 3DCRT+VMAT plan was required less monitor units and treatment time compared to other plans. CONCLUSION: The overall plan quality score that integrated the dosimetric parameters of PTV and OARs indicated that the 3DCRT+VMAT hybrid plan is superior for SBBC treatment.

Evaluation of lung tumor motion in a large sample: Target-related and clinical factors influencing tumor motion based on four-dimensional CT.

BACKGROUND AND PURPOSE: We aimed to analyze the influence of target-related and clinical factors on lung tumor motion based on four-dimensional CT (4DCT), and clarify the motion based on subgroups in lung stereotactic body radiation therapy. MATERIALS AND METHODS: 4DCT image data of 267 tumors from 246 patients were analyzed. The coordinates in the left-right (LR), anterior-posterior (AP), and cranial-caudal (CC) directions of the center of mass (COM) of the gross tumor volumes in 10 phases of 4DCT were measured. The peak-to-peak COM displacement in the LR, AP, CC, and 3D directions was calculated. The influence of target-related and clinical factors on tumor motion was evaluated using multivariate analysis. RESULTS: The tumor segment location correlated with the tumor motion in each direction. Tumor size was predictive of tumor motion in the 3D (p = 0.023) and AP directions (p = 0.049). The tumor motion for metastatic tumors was smaller than that for primary tumors in the LR (p = 0.019) and AP directions (p = 0.008). The CC motion for pulmonary surgery recipients (3.8 ± 4.5 mm) was less than that for patients who had not undergone surgery (5.6 ± 5.4 mm), and no significant clinical factor was observed. BSA and BMI were positively correlated with the motion in the CC (p = 0.02) and LR directions (p = 0.002). CONCLUSION: The tumor segment location was a good predictor of tumor motion. A larger tumor tends to have a smaller motion. Patients with metastatic tumors or those who have undergone pulmonary surgery exhibited smaller and more unpredictable tumor motions, which required individual assessments. Thus, clinical factors can potentially predict tumor motion.

Synchronous bilateral breast cancer treated with a 3-week hypofractionated radiotherapy schedule: clinical and dosimetric outcomes

Background and purpose Synchronous bilateral breast cancer (SBBC) accounts for 1–3.5% of breast cancer patients. The aim of this study was to evaluate dosimetric issues, clinical outcomes, and acute toxicities for SBBC patients receiving synchronous bilateral hypofractionated radiotherapy (SBHRT) and to compare them with patients treated with synchronous bilateral normofractionated RT schedule (SBNRT). Materials and methods From April 2016 to March 2020, 39 SBBC patients were referred to our institution. Patients were divided according to their prescription dose: Group A: 50 Gy/25fx (fractions), B: 60–64 Gy/25fx, C: 40.05 Gy/15fx; D: 48 Gy/15fx. Toxicity was evaluated using Common Terminology Criteria for Adverse Events (CTCAE)v.5.0. Results 34 patients were finally evaluated. Median follow-up was 24 months for NF schedule and 9 months for HF schedule. In the HF schedule, no acute side-effects > G2 were observed and no dermatitis was reported in 6th month´s assessments. 95% of patients have no evidence of disease and only 1 patient presented local relapse in the first mammography after RT. No distant failures or deaths were observed. Regarding dosimetric issues, the inter-patient average Dmean for the heart was: Group A: 5.0 Gy (4.6–5.5), Group B: 4.4 Gy (4.1–5.4), Group C: 4.8 Gy (4.5–5.1) and Group D: 5.3 Gy (4.4–5.6). For the lungs, the inter-patient average Dmean was: Group A: 10.8 Gy (9.8–12.2), Group B: 11.5 Gy (11.3–12), Group C: 9.8 Gy (9.3–10.5) and Group D: 10.5 Gy (10–11.3). Conclusions This is the first study reporting the safety, feasibility, and tolerability of 40.05 Gy/15fx over 3 weeks for the treatment of SBBC patients. Further study with larger accrual is mandatory (AU)

Synchronous bilateral breast cancer treated with a 3-week hypofractionated radiotherapy schedule: clinical and dosimetric outcomes.

BACKGROUND AND PURPOSE: Synchronous bilateral breast cancer (SBBC) accounts for 1-3.5% of breast cancer patients. The aim of this study was to evaluate dosimetric issues, clinical outcomes, and acute toxicities for SBBC patients receiving synchronous bilateral hypofractionated radiotherapy (SBHRT) and to compare them with patients treated with synchronous bilateral normofractionated RT schedule (SBNRT). MATERIALS AND METHODS: From April 2016 to March 2020, 39 SBBC patients were referred to our institution. Patients were divided according to their prescription dose: Group A: 50 Gy/25fx (fractions), B: 60-64 Gy/25fx, C: 40.05 Gy/15fx; D: 48 Gy/15fx. Toxicity was evaluated using Common Terminology Criteria for Adverse Events (CTCAE)v.5.0. RESULTS: 34 patients were finally evaluated. Median follow-up was 24 months for NF schedule and 9 months for HF schedule. In the HF schedule, no acute side-effects > G2 were observed and no dermatitis was reported in 6th month´s assessments. 95% of patients have no evidence of disease and only 1 patient presented local relapse in the first mammography after RT. No distant failures or deaths were observed. Regarding dosimetric issues, the inter-patient average Dmean for the heart was: Group A: 5.0 Gy (4.6-5.5), Group B: 4.4 Gy (4.1-5.4), Group C: 4.8 Gy (4.5-5.1) and Group D: 5.3 Gy (4.4-5.6). For the lungs, the inter-patient average Dmean was: Group A: 10.8 Gy (9.8-12.2), Group B: 11.5 Gy (11.3-12), Group C: 9.8 Gy (9.3-10.5) and Group D: 10.5 Gy (10-11.3). CONCLUSIONS: This is the first study reporting the safety, feasibility, and tolerability of 40.05 Gy/15fx over 3 weeks for the treatment of SBBC patients. Further study with larger accrual is mandatory.

Convexity Meningiomas in Patients with Neurofibromatosis Type 2: Long-Term Outcomes After Gamma Knife Radiosurgery.

BACKGROUND: Convexity meningiomas are common tumors requiring treatment in patients with neurofibromatosis type 2 (NF2). Although different therapeutic options are described for sporadic convexity meningioma, much less is known about these lesions in patients with NF2 despite their distinct biology and need for multiple treatments. We analyzed the value of Gamma Knife radiosurgery (GKRS) as definitive treatment for convexity meningiomas in patients with NF2. METHODS: This international multicenter retrospective study was approved by the International Radiosurgery Research Foundation. Patients with NF2 with at least 1 convexity meningioma and 6-month follow-up after primary GKRS were included. RESULTS: Inclusion criteria were met by 18 patients with NF2. A total of 120 convexity meningiomas (median treatment volume, 0.66 cm3 [range, 0.10-21.20 cm3]) were analyzed. Median follow-up after initial GKRS was 15.6 years (range, 0.6-25.5 years). Median age at GKRS was 32.5 years (range, 16-53 years). Median number of meningiomas per patient was 13 (range, 1-27), and median number of convexity lesions receiving GKRS per patient was 3.5 (range, 1-27). One case of tumor progression was reported 24 years after GKRS, leading to actuarial progression-free survival rates of 100% at 2, 5, and 10 years. No malignant transformation or death due to meningioma or radiosurgery was recorded. CONCLUSIONS: GKRS is safe and effective as definitive treatment of small to medium-sized convexity meningiomas in patients with NF2. Despite concerns about the particular mutational burden of these tumors, no malignant transformation manifested after treatment. GKRS represents a minimally invasive option that offers long-term tumor control to this specific group of patients.

Synchronous bilateral breast cancer patients treated with hypofractionated bilateral breast irradiation: A dosimetric and clinical study.

BACKGROUND: Bilateral breast irradiation is technically challenging and there is limited information regarding optimal technique and outcomes. Hypofractionated Radiotherapy (HFRT) has emerged as the new standard of care in early breast cancer. However, there are concerns in using hypofractionation for bilateral breast irradiation due to larger volumes and potential toxicity. Our aim was to analyze the dosimetric data and clinical outcomes in these patients. MATERIALS AND METHODS: Patients with synchronous bilateral breast cancer (SBBC) treated with bilateral breast irradiation were analyzed. All patients received simultaneous bilateral breast with or without regional nodal irradiation using a hypofractionated schedule of 40 Gy in 15 fractions over 3 weeks with single isocenter bi-tangential field-in-field intensity-modulated radiation therapy (FIF-IMRT) technique. RESULTS: Seven patients of SBBC were treated at our institute from 2015 to 2017. All patients were postmenopausal females. Five patients underwent bilateral modified radical mastectomy; two patients underwent bilateral breast conservative surgery. All patients received systemic anthracycline-based chemotherapy. The mean cardiac dose was 3.73 ± Gy and V 25 was 3.26% ± 1.96%. V 20 of lung ranged from 23.48% ± 4.47% and the mean esophageal dose was 3.6 ± 2.00 Gy. No patient had acute toxicity higher than Grade 2. At a median follow-up of 48 months, one patient died due to systemic progression. No patient reported any late toxicity. CONCLUSION: Bilateral breast irradiation using a hypofractionated schedule with single isocenter FIF-IMRT technique is technically feasible with minimal acute toxicity and no significant late effects on early follow-up.

Synchronous thoracic and head-and-neck malignancies-double trouble-challenges, pitfalls, and lessons learnt.

Synchronous malignancies arising from head and neck and thorax are rare presentation, and only few cases are reported in the scientific literature. We report three cases of double primary malignancies treated at our hospital.

Time-Driven Activity-Based Costing Comparison of Stereotactic Radiosurgery to Multiple Brain Lesions Using Single-Isocenter Versus Multiple-Isocenter Technique.

PURPOSE: Stereotactic radiosurgery (SRS) historically has been used to treat multiple brain lesions using a multiple-isocenter technique-frequently associated with significant complexity in treatment planning and long treatment times. Recently, given innovations in planning algorithms, patients with multiple brain lesions may now be treated with a single-isocenter technique using fewer total arcs and less time spent during image guidance (though with stricter image guided radiation therapy tolerances). This study used time-driven activity-based costing to determine the difference in cost to a provider for delivering SRS to multiple brain lesions using single-isocenter versus multiple-isocenter techniques. METHODS AND MATERIALS: Process maps, consisting of discrete steps, were created for each phase of the SRS care cycle and were based on interviews with department personnel. Actual treatment times (including image guidance) were extracted from treatment record and verify software. Additional sources of data to determine costs included salary/benefit data of personnel and average list price/maintenance costs for equipment. RESULTS: Data were collected for 22 patients who underwent single-isocenter SRS (mean lesions treated, 5.2; mean treatment time, 30.2 minutes) and 51 patients who underwent multiple-isocenter SRS (mean lesions treated, 4.4; mean treatment time, 75.2 minutes). Treatment time for multiple-isocenter SRS varied substantially with increasing number of lesions (11.8 minutes/lesion; P < .001), but to a much lesser degree in single-isocenter SRS (1.8 minutes/lesion; P = .029). The resulting cost savings from single-isocenter SRS based on number of lesions treated ranged from $296 to $3878 for 2 to 10 lesions treated. The 2-mm planning treatment volume margin used with single-isocenter SRS resulted in a mean 43% increase of total volume treated compared with a 1-mm planning treatment volume expansion. CONCLUSIONS: In a comparison of time-driven activity-based costing assessment of single-isocenter versus multiple-isocenter SRS for multiple brain lesions, single-isocenter SRS appears to save time and resources for as few as 2 lesions, with incremental benefits for additional lesions treated.

The Role of Reconstructive Surgery and Brachytherapy in Pediatric Bladder/Prostate Rhabdomyosarcoma.

PURPOSE: The surgical approach to localized bladder/prostate rhabdomyosarcoma in children may change due to a new radiotherapeutic modality. We assessed the impact of brachytherapy following surgery for local tumor control, and report surgical techniques and outcomes. MATERIALS AND METHODS: We retrospectively analyzed the records of all children who underwent surgery for bladder/prostate rhabdomyosarcoma, including tumor relapse, at our institution from 2009 onward. RESULTS: A total of 38 patients with a median age of 29 months (range 10 to 134) met inclusion criteria. Five-year overall survival was 92.8% (95% CI 72.9 to 98.1), and event-free survival at a median followup of 12 months (range 3 to 111) was 73.7% (95% CI 53.4 to 86.2). Three treatment groups were defined, ie bladder preserving surgery combined with brachytherapy, bladder preserving surgery alone and cystectomy. Five-year event-free survival rates for the 3 groups were 85.6% (95% CI 61.2 to 95.2), 66.7% (95% CI 27.2 to 88.2) and 50% (95% CI 5.8 to 84.5), respectively. Bladder preserving surgery was performed in 33 patients (87%), of whom 23 (70%) also underwent brachytherapy, while cystectomy was performed in 5 (13%). Reconstructive procedures varied depending on tumor location and spread. CONCLUSIONS: Combining brachytherapy with surgery results in a high bladder preservation rate and improves event-free survival compared to surgery alone in children with bladder/prostate rhabdomyosarcoma. The combination is also effective in treating local tumor relapse, and is associated with less extensive reconstructive procedures due to exclusion of tumors of unfavorable size and location for brachytherapy.

Coexistence of anal malignant melanoma and papillary renal cell cancer: An interesting coexistence.

Coexistence of malignant melanoma and renal cell cancer (RCC) is a rare phenomenon, but this issue becomes increasingly popular. The objective of the current study is to present a case with coexistent anorectal melanoma (ANM) and papillary RCC detected. A 61-year-old female admitted to our clinic with complaints of blood in the stool. ANM diagnosed with colonoscopic biopsy and a mass lession with a size of 57 mm × 53 mm suggesting RCC was detected in the left kidney during staging procedure. Transabdominal resection and radical nephrectomy were performed and diagnoses of ANM and papillary RCC were confirmed. Adjuvant radiotherapy was applied for ANM. The patient is still under follow-up for 6 months and no recurrence or progression was detected. To the best of our knowledge, this is the first report of this interesting coexistency.

Dosimetric comparison of helical tomotherapy, volumetric-modulated arc therapy, intensity-modulated radiotherapy, and field-in-field technique for synchronous bilateral breast cancer.

PURPOSE: To compare the dosimetric characteristics of helical tomotherapy (HT), volumetric-modulated arc therapy (VMAT), intensity-modulated radiotherapy (IMRT), and tangential field-in-field technique (FIF) for the treatment of synchronous bilateral breast cancer (SBBC). METHODS AND MATERIALS: Ten patients with early-stage unilateral breast cancer were selected for simulating the patients with SBBC in this retrospective analysis. Treatment plans with HT, VMAT, IMRT, and FIF were generated for each patient with a total dose of 50.4 Gy in 28 fractions to the target. Plan quality, namely conformity index (CI), homogeneity index (HI), dose-volume statistics of organs at risk (OARs), and beam-on time (BOT), were evaluated. RESULTS: HT plans showed a lower mean heart dose (3.53 ± 0.31Gy) compared with the other plans (VMAT = 5.6 ± 1.36 Gy, IMRT = 3.80 ± 0.76 Gy, and FIF = 4.84 ± 2.13 Gy). Moreover, HT plans showed a significantly lower mean lung dose (p < 0.01) compared with the other plans: mean right lung doses were 6.81 ± 0.67, 10.32 ± 1.04, 9.07 ± 1.21, and 10.03 ± 1.22 Gy and mean left lung doses were 6.33 ± 0.87, 8.82 ± 0.91, 7.84 ± 1.07, and 8.64 ± 0.99 Gy for HT, VMAT, IMRT, and FIF plans, respectively. The mean dose to the left anterior descending artery was significantly lower in HT plans (p < 0.01) than in the other plans: HT = 19.41 ± 0.51 Gy, VMAT = 25.77 ± 7.23 Gy, IMRT = 27.87 ± 6.48 Gy, and FIF = 30.95 ± 10.17 Gy. FIF plans showed a worse CI and HI compared with the other plans. VMAT plans showed shorter BOT (average, 3.9 ± 0.2 minutes) than did HT (average, 11.0 ± 3.0 minutes), IMRT (average, 6.1 ± 0.5 minutes), and FIF (average, 4.6 ± 0.7 minutes) plans. CONCLUSIONS: In a dosimetric comparison for SBBC, HT provided the most favorable dose sparing of OARs. However, HT with longer BOT may increase patient discomfort and treatment uncertainty. VMAT enabled shorter BOT with acceptable doses to OARs and had a better CI than did FIF and IMRT.

Gamma Knife Radiosurgery for Patients with Multiple Intracranial Meningiomas.

OBJECTIVE: The aim of this study was to evaluate the safety and efficacy of Gamma Knife radiosurgery (GKRS) in patients with multiple intracranial meningiomas (MIMs). METHODS: The authors performed a retrospective analysis of 42 consecutive patients (7 men and 35 women) with MIMs who underwent GKRS. The median age of the patients at the time of GKRS was 57.5 years (range, 27-77 years). A total of 115 tumors among 42 patients were identified through imaging or postoperative histopathologic examination, of which 90 were treated with GKRS. RESULTS: Follow-up imaging studies were available for 75 tumors in 36 patients (83.3%), with a mean follow-up period of 45.0 months (range, 6.6-90.4 months); 41 patients (97.6%) received clinical follow-up for 16.7 to 106.7 months (average, 57.1 months). Local tumor control was achieved in 68 tumors (90.7%) at the last follow-up. On univariate analysis, surgical resection before GKRS more than once (P = 0.048) and high World Health Organization (WHO) classification (grades II and III) (P = 0.001) were associated with tumor progression. Patients with worsening clinical manifestation showed correlation with peritumor edema (P < 0.001) and had >2 lesions treated by GKRS (P < 0.001) on univariate analysis. CONCLUSIONS: GKRS is a safe and effective treatment for MIMs. Variables including surgical resection before GKRS more than once, high grade WHO classification, peritumor edema, and >2 tumors treated by GKRS are predictors of unfavorable outcome after GKRS.

Multifocal Infratentorial Pilocytic Astrocytoma in an Adult Patient.

BACKGROUND: Pilocytic astrocytoma is a benign glial tumor typically presenting in children. It is rare for adults to present with pilocytic astrocytoma and even less likely to manifest with multiple foci of lesions especially in nonoptic or hypothalamic locations. CASE DESCRIPTION: Our patient was a 37-year old man presenting with varied cranial neuropathies, cerebellar dysfunction, and long tract signs, with imaging demonstrating 3 discrete ill-defined contrast-enhancing lesions affecting the cerebellar peduncles, brainstem, and cervicomedullary junction. Neuronavigation-guided biopsy confirmed World Health Organization grade 1 pilocytic astrocytoma; the patient was treated with radiotherapy. CONCLUSIONS: To our knowledge, we believe this is the first reported case with multifocal infratentorial pilocytic astrocytoma on presentation in an adult patient in the absence of a prior history of associated risk factors such as neurofibromatosis 1 or chemoradiotherapeutic intervention.

Unusual presentation for small lymphocytic lymphoma: Case report of a man with bilateral ear involvement and review of the literature.

INTRODUCTION: Ear involvement by non-Hodgkin lymphoma is quite rare and can be mistaken for other common lesions encountered in otolaryngology. The literature on this subject is also limited. CASE SUMMARY: A 45-year-old man with bilateral ear nodules that progressed over two years. Biopsy of the right ear revealed a B-cell small lymphocytic lymphoma (SLL). The patient responded to radiotherapy well. He received an additional dose two months after the initial treatment because of a remaining nodularity on the right earlobe. After several months, he presented a new lesion on his nasal tip, for which a biopsy confirmed a lymphoma relapse. The patient was managed with oral prednisone and low-dose radiation with a favourable response. DISCUSSION: This case highlights the importance of including lymphoma in the differential diagnosis of ear lesions from an otolaryngology perspective. A biopsy of any lesion or nodule with an atypical course should be considered for appropriate diagnosis and management.

Skin and lung toxicity in synchronous bilateral breast cancer treated with volumetric-modulated arc radiotherapy: a mono-institutional experience.

PURPOSE: To evaluate acute and late skin/subcutaneous toxicities and radiation-induced lung fibrosis (RILF) in patients treated with adjuvant radiotherapy (RT) for synchronous bilateral breast cancers (SBBC), after conservative surgery. METHODS/PATIENTS: Twenty-five patients were treated with volumetric-modulated arc therapy (VMAT/RapidArc®) on both breasts, and checked clinically for detecting RT toxicities during and after treatment. A high-resolution computed tomography (HRCT) was performed, for detecting RILF during follow-up. RESULTS: We registered acute Grade-1 skin toxicity in 18 patients (72%), while six patients (24%) experienced Grade-2 toxicity. No breath symptoms were reported during and after RT. Late Grade-1 subcutaneous toxicity and late Grade-2 skin toxicity were registered in four patients (16%) and one patient (4%), respectively, at a mean follow-up of 36 months. Grade-1 RILF was detected in six patients (30%). The median volume of fibrosis area was 6.5 cc (range 1.3-21.5 cc). The partial volumes receiving a specified dose (V20, V30, V40, and V50) in patients who developed lung fibrosis were significantly bigger than who did not (p < 0.01). We showed that the mean volume of the tumour boost of patients who developed fibrosis (77.7 cc) was not significantly different from the other patients (90.8 cc) (p = 0.5). CONCLUSION: The clinical impact of this technique is favourable, and this is the first clinical study showing RILF by HRCT in a setting of SBBC. Further study with larger accrual is mandatory.

Dose to the dominant intraprostatic lesion using HDR vs. LDR monotherapy: A Phase II randomized trial.

PURPOSE: To present the dosimetric results of a Phase II randomized trial comparing dose escalation to the MRI-defined dominant intraprostatic lesion (DIL) using either low-dose-rate (LDR) or high-dose-rate (HDR) prostate brachytherapy. MATERIAL AND METHODS: Patients receiving prostate brachytherapy as monotherapy were randomized to LDR or HDR brachytherapy. Prostate and DILs were contoured on preoperative multiparametric MRI. These images were registered with transrectal ultrasound for treatment planning. LDR brachytherapy was preplanned using I-125 seeds. HDR brachytherapy used intraoperative transrectal ultrasound-based planning to deliver 27 Gy/2 fractions in separate implants. DIL location was classified as peripheral, central, or anterior. A student t-test compared DIL D90 between modalities and DIL locations. RESULTS: Of 60 patients, 31 underwent LDR and 29 HDR brachytherapy. Up to three DILs were identified per patient (100 total) with 74 peripheral, six central, and 20 anterior DILs. Mean DIL volume was 1.9 cc (SD: 1.7 cc) for LDR and 1.6 cc (SD 1.3 cc) for HDR (p = 0.279). Mean DIL D90 was 151% (SD 30%) for LDR and 132% (SD 13%) for HDR. For LDR, mean peripheral DIL D90 was 159% (SD 27%) and central or anterior 127% (SD 13%). HDR peripheral DILs received 137% (SD 12%) and central or anterior 119% (SD 7%). DIL D90 for peripheral lesions was higher than anterior and central (p < 0.001). CONCLUSIONS: DIL location affects dose escalation, particularly because of urethral proximity, such as for anterior and central DILs. HDR brachytherapy may dose escalate better when target DIL is close to critical organs.

Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer: A Primer for Radiologists.

The past 2 decades have seen a rapid growth in use of stereotactic body radiation therapy (SBRT) for the management of non-small cell lung cancer (NSCLC). Not only is SBRT the reference standard for treatment of early-stage node-negative NSCLC in medically inoperable patients, it is also currently challenging the role of surgery for early-stage operable disease. SBRT is also used to treat recurrent disease and has a role in the management of multiple synchronous lung cancers. Imaging changes after SBRT differ from the changes after conventional radiation therapy in many ways, the knowledge of which is pertinent for accurate image interpretation. Posttreatment response assessment and detection of recurrent disease are heavily reliant on radiologic assessment, and often the decision to treat recurrent disease is based on the imaging findings themselves. This article provides a comprehensive review of the concepts of SBRT and the current indications for its use in the treatment of early-stage NSCLC, as well as a discussion of the CT findings seen after SBRT compared with the changes after conventional radiation therapy. Radiologic findings that are suggestive of recurrent disease and the imaging pitfalls are also highlighted. Finally, the rare complications after SBRT are described. SBRT is a major component of the changing treatment paradigms for early- and late-stage NSCLC. The imaging findings after SBRT often determine the next steps in a patient's clinical management. Therefore, radiologists must be familiar with the uses of this therapy and its radiologic appearance to be able to effectively contribute to the care of patients with NSCLC. ©RSNA, 2018.

Combination Ipsilateral Lobar and Segmental Radioembolization Using Glass Yttrium-90 Microspheres for Treatment of Multifocal Hepatic Malignancies.

Eight patients with primary (n = 6) and metastatic (n = 2) disease of the liver underwent yttrium-90 radioembolization with glass microspheres using a combination of segmental and ipsilateral lobar approach to treat multifocal tumors containing a single dominant tumor. The superselective dose was administered to the dominant tumor, whereas lobar infusion was used for smaller tumors. Assuming uniform distribution, median dose to the segment with dominant tumor was 412.3 Gy and to the remaining lobe was 117.5 Gy. No instances of radiation-induced liver disease occurred. Combined segmental and ipsilateral lobar radioembolization is a well-tolerated procedure to treat unilateral multifocal hepatic tumors including a single dominant tumor.