Efficacy and feasibility of 3D printed redesigned Venezia™ applicator for treating advanced cervix and recurrent endometrial cancer.

PURPOSE: Venezia™ is an interstitial brachytherapy applicator for treating advanced cervical and vaginal vault recurrent cancer. However, there are limitations that lead to suboptimal target coverage. 3D printing introduction allows the redesign of Venezia™ for bulky and irregular-shaped tumors. METHODS: This study first describes three new designs included: 1) add-on needles template allowed for an extra layer of straight and oblique needles, 2) redesigned vaginal cap so straight and oblique needles can be used together and 3) redesigned central tube allowed vaginal vault interstitial needle insertion. Drawbacks to original Venezia™ and rationale for using these new designs were discussed. Dosimetric analysis by comparing the original Venezia™ with new design for 10 cases in Oncentra treatment planning system v4.5 (Elekta, Stockholm, Sweden) to observe the dose differences in gross tumor volume (GTV), high risk clinical target volume (HRCTV), intermediate clinical target volume (IRCTV) and organs at risk. RESULTS: For the dosimetric comparison, there were statistically significantly increased median minimal dose to 98% (D98%) of GTV, 90% (D90%) of HRCTV, and IRCTV for the new design with p-value of 0.008, 0.005 and 0.0018, respectively. Comparing the physical dose of D98% of GTV, D90% of HRCTV, and IRCTV when using the new design, it averagely increased by 11.7%, 8.0%, 19.4%, respectively per fraction. CONCLUSIONS: Dosimetric comparison revealed the new designs increased the dose to GTV, HRCTV and IRCTV and fulfilled the dose constraints of bladder, rectum and sigmoid. The 3D printed new design is biocompatible, inexpensive and can be patient specific.

Dosimetric benefits of 3D-printed modulated electron bolus following lumpectomy and whole-breast radiotherapy for left breast cancer.

Radiotherapy with electrons is commonly applied to the tumor bed after whole-breast radiotherapy following breast conservation surgery for breast cancer patients. However, the radiation dose to adjacent organs-at-risk (OARs) and conformity of planning target volume (PTV) cannot be optimized. In this study, we examine the feasibility of using modulated electron bolus (MEB) to improve PTV conformity and reduce the dose to these OARs. Twenty-seven patients with left breast cancer were retrospectively selected in this study. For each patient, a tangential photon plan in RayStation treatment planning system with prescription of 26 Gy in 5 fractions was created as base plan. Two electron plans, one without bolus and one with MEB using Adaptiiv software based on the PTV were created. Various dosimetric parameters of OARs including left lung, heart, left anterior descending artery (LAD) and ribs and the conformity indices of PTV of these 2 electron plans together with the base plans were compared. Statistically significant decreases in the dosimetric parameters (V5Gy, V10Gy, V20Gy, and mean dose) of the ipsilateral left lung and the heart were observed with MEB. The median maximum dose to the LAD and the ribs decreased by 6.2% and 4.5% respectively. The median conformity index was improved by 14.3% with median increases of monitor units by 1.7%. Our results show that MEB is feasible resulting in reduction of doses to the predefined OARs and an improved conformity of PTV. By using 3D printing, MEB might be considered as an alternative to conventional electron boost.

Palliative Liver Radiotherapy (RT) for Symptomatic Hepatocellular Carcinoma (HCC).

This study aims at evaluating the symptom response, response duration, and toxicity of single dose palliative liver radiotherapy (RT) for symptomatic HCC patients. We reviewed unresectable HCC patients treated with palliative RT in our institution. Eligible patients were unsuitable or refractory to trans-arterial chemoembolization (TACE) and stereotactic body radiotherapy (SBRT), with an index symptom of pain or abdominal discomfort. The primary outcome was the percentage of patients with clinical improvement of index symptom at 1 month. Secondary outcomes were response duration, toxicities, alpha-feto protein (AFP) response, and radiological response. Fifty-two patients were included in the study. The index symptom was pain in 34 patients (65.4%), and abdominal discomfort (34.6%) in 18 patients. At 1 month, 51.9% of patients had improvement of symptoms. Median time to symptom progression was 89 days (range: 12-392 days). Treatment was well tolerated with only 2 patients (3.8%) developing grade 3 GI toxicities. AFP response, radiological response rate, and disease control rate at 3 months were 48.6%, 15.1%, and 54.5% respectively. Half of the patients had improvement of index symptoms after receiving palliative liver RT with median response duration of 3 months. The treatment was well tolerated with minimal toxicities.

Linking dose delivery accuracy and planning target margin in radiosurgery based on dose-volume histograms derived from measurement-guided dose reconstruction.

In radiosurgery (SRS), the geometric uncertainties of machine-related delivery including image-guidance and hence the planning target volume (PTV) are often evaluated by the end-to-end gamma (γ) comparison that carries no information about the clinical relevance of deviations of individual SRS plans during delivery quality assurance (DQA). A proof-of-concept method was proposed to derive the PTV against both the plan- and the machine-specific delivery errors directly from the clinically relevant dose-volume histograms (DVHs) using measured-guided dose reconstruction (MGDR) during DQA. A liquid-filled detector array and a rotating phantom were used to measure sixteen arc-based radiosurgery treatments with 1 and 2 mm gross tumor volume (GTV)-to-PTV margins, producing MGDR-3D dose distribution on both the phantom and the patient CT for γ index and clinical DVH evaluations, respectively. The PTV was considered optimal when the MGDR showed the desired prescription dose coverage (V pres ) of the GTV (100% in this study). Associations of the binary V pres outcomes (

Combined stereotactic body radiotherapy and trans-arterial chemoembolization as initial treatment in BCLC stage B-C hepatocellular carcinoma.

PURPOSE: We retrospectively evaluated the efficacy and safety of stereotactic body radiotherapy (SBRT) combined with trans-arterial chemoembolization (TACE) as initial therapy in Barcelona Clinic Liver Cancer (BCLC) system stage B-C hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Seventy-two patients received a single dose of TACE followed by SBRT 4 weeks later. All patients had tumor sizes ≥5 cm, at least 700 ml of disease-free liver, Child-Pugh (CP) score ≤ B7 and tumor nodules ≤5. SBRT dose, ranging from 6â€¯× 5-8 Gy or 5-10â€¯× 4 Gy, was individualized according to normal tissue constraints. No subsequent scheduled treatment was delivered unless disease progression was observed. Local control (LC), overall survival (OS), progression-free survival (PFS), response rate (RR), and toxicity were evaluated. RESULTS: The patients' characteristics were: median age 60 years (range 28-87 years); CP score A/B (n = 68/4); BCLC stage B/C (n = 51/21); solitary/multifocal (n = 37/35); portal vein invasion (n = 18). The median tumor size and GTV were 11.2 cm (range 5.0-23.6 cm) and 751 cm3 (range 41-4009 cm3), respectively. The median equivalent dose in 2 Gy per fraction (EQD2, α/ß = 10) was 37.3 Gy2 (range, 28-72 Gy2). The median follow-up time was 16.8 months (range, 3-96 months). The objective RR was 68% and the 1­year LC rate was 93.6% (95% CI, 87.6-100%). The median OS was 19.8 months (95% CI, 11.6-30.6 months). SBRT-related grade 3 or higher adverse gastrointestinal events and treatment-related death occurred in three (2.8%) and one patient (1.4%) respectively. No patient developed classical radiation-induced liver injury. CONCLUSION: Our experience suggests that combined TACE and SBRT can be a safe and effective initial therapy for BCLC stage B-C HCC with appropriate patient selection. Further prospective trials are warranted.

Feasibility study of robotic hypofractionated lung radiotherapy by individualized internal target volume and XSight Spine Tracking: a preliminary dosimetric evaluation.

AIM: To investigate the dosimetric impacts of lung tumor motion in robotic hypofractionated radiotherapy for lung cancers delivered through continuous tracking of the vertebrae by the XSight Spine Tracking (XST) mode of the CyberKnife. MATERIALS AND METHODS: Four-dimensional computed tomography (4DCT) scans of a dynamic thorax phantom were acquired. Three motion patterns (one-dimensional and three-dimensional) of different range were investigated. Monte Carlo dose distributions were generated with 4DCT-derived internal target volume (ITV) with a treatment-specific setup margin for 12.6 Gy/3 fractions. Six-dimensional error correction was performed by kV stereoscopic imaging of the phantom's spine. Dosimetric effects of intrafractional tumor motion were assessed with Gafchromic films (Ashland Inc, Wayne, NJ, USA) according to 1) the percent measurement dose points having doses above the prescribed (P (> Dpres)), mean (P (> Dm)), and minimum (P (> Dmin)) ITV doses, and 2) the coefficient of variation (CV). RESULTS: All plans attained the prescription dose after three fractions despite marked temporal dose variations. The value of P (> Dpres) was 100% after three fractions for all plans, but could be smaller (~96%) for one fraction. The values of P (> Dmin) and P (> Dm) varied drastically interfractionally (25%-2%), and could be close to 0% after three fractions. The average CV ranged from 2.8% to 7.0%. Correlations with collimator size were significant for P (> Dmin) and P (> Dm) (P < 0.05) but not P (> Dpres) (P > 0.05). CONCLUSIONS: Treating lung tumors with CyberKnife through continuous tracking of the vertebrae should not be attempted without effective means to reduce the amplitude and variability of target motion because temporal dose variations owing to the intrafractional target motion can be significant.