Re-irradiation of a Classic Kaposi's Sarcoma Using Volumetric Modulated Arc Therapy.

A black male in his 60s diagnosed with classic Kaposi's sarcoma presented with multiple cutaneous nodules and edema of the right foot and lower leg. He was initially treated with alitretinoin 1% topical treatment. However, 16 months after treatment with the alitretinoin, the skin lesions progressed, and he subsequently underwent a course of radiation therapy to a total dose of 2000 centigrays (cGy) in five fractions to his right foot and lower extremities. Approximately 1.5 years after the radiation therapy was completed, multiple new lesions developed on the right foot and distal lower leg. He then underwent a course of re-irradiation to this area using volumetric modulated arc therapy (VMAT) to a total dose of 3300 cGy in 11 fractions. At a four-week follow-up visit, the skin lesions had completely resolved; however, the patient experienced mild edema and tenderness of the right foot and lower leg. Although long-term outcomes need to be followed, re-irradiation showed positive short-term outcomes for classic Kaposi's sarcoma.

Total body irradiation delivered using a dedicated Co-60 TBI unit: Evaluation of dosimetric uniformity and dose verification.

This work presents the dosimetric characteristics of Total Body Irradiation (TBI) delivered using a dedicated Co-60 TBI unit. We demonstrate the ability to deliver a uniform dose to the entire patient without the need for a beam spoiler or patient-specific compensation. Full dose distributions are calculated using an in-house Monte Carlo treatment planning system, and cumulative dose distributions are created by deforming the dose distributions within two different patient orientations. Sample dose distributions and profiles are provided to illustrate the plan characteristics, and dose and DVH statistics are provided for a heterogeneous cohort of patients. The patient cohort includes adult and pediatric patients with a range of 132-198 cm in length and 16.5-37.5 cm in anterior-posterior thickness. With the exception of the lungs, a uniform dose of 12 Gy is delivered to the patient with nearly the entire volume receiving a dose within 10% of the prescription dose. Mean lung doses (MLDs) are maintained below the estimated threshold for radiation pneumonitis, with MLDs ranging from 7.3 to 9.3 Gy (estimated equivalent dose in 2 Gy fractions (EQD2 ) of 6.2-8.5 Gy). Dose uniformity is demonstrated across five anatomical locations within the patient for which mean doses are all within 3.1% of the prescription dose. In-vivo dosimetry demonstrates excellent agreement between measured and calculated doses, with 78% of measurements within ±5% of the calculated dose and 99% within ±10%. These results demonstrate a state-of-the-art TBI planning and delivery system using a dedicated TBI unit and hybrid in-house and commercial planning techniques which provide comprehensive dosimetric data for TBI treatment plans that are accurately verified using in-vivo dosimetry.

A Direct Patient-Provider Relationship With the Medical Physicist Reduces Anxiety in Patients Receiving Radiation Therapy.

PURPOSE: The complex technological processes involved in radiation therapy can be intimidating to patients, causing increased treatment-related anxiety and reduced satisfaction. An intervention was implemented to provide direct consultations between patients and medical physicists to reduce patient anxiety and improve patient satisfaction. A randomized clinical trial was conducted to test the intervention's effect on anxiety, distress, treatment adherence, technical understanding, and satisfaction in patients receiving radiation therapy. METHODS AND MATERIALS: Eligible patients were recruited into "intervention" and "standard of care" arms within a phase 2 screening randomized trial. Intervention-arm patients met with a medical physicist who provided technical information and addressed patient questions or concerns at the time of treatment simulation and before the first treatment. In addition to baseline information collected before randomization, participants were surveyed (1) before simulation, (2) before the first treatment, and (3) before the completion of treatment to evaluate the study endpoints. Primary endpoints included patient anxiety and distress. Secondary endpoints included patient treatment adherence, overall satisfaction, and technical understanding of treatment. Patients in the intervention arm were surveyed before and after each physicist meeting. RESULTS: Participant anxiety was significantly reduced in the intervention arm (difference, -0.29; 95% confidence interval, -0.57 to -0.02; P = .038). No differences in distress or treatment adherence were observed between groups. Although measures of technical understanding and satisfaction were evaluated as exploratory objectives, participants in the intervention group were more likely to feel that technical aspects of treatment were adequately explained (difference, 0.78; 95% confidence interval, 0.03-1.54), and all measures of technical understanding and satisfaction were considerably higher in the intervention group at the time of the first visit. CONCLUSIONS: The establishment of a direct patient-provider relationship with the medical physicist reduced anxiety in patients receiving radiation therapy. In addition, increases in patient understanding of the technical aspects of care and in satisfaction were observed at the initiation of treatment.

Commissioning of a dedicated commercial Co-60 total body irradiation unit.

We describe the commissioning of the first dedicated commercial total body irradiation (TBI) unit in clinical operation. The Best Theratronics GammaBeam 500 is a Co-60 teletherapy unit with extended field size and imaging capabilities. Radiation safety, mechanical and imaging systems, and radiation output are characterized. Beam data collection, calibration, and external dosimetric validation are described. All radiation safety and mechanical tests satisfied relevant requirements and measured dose distributions meet recommendations of American Association of Physicists in Medicine (AAPM) Report #17. At a typical treatment distance, the dose rate in free space per unit source activity using the thick flattening filter is 1.53 × 10-3 cGy*min-1 *Ci-1 . With a 14,000 Ci source, the resulting dose rate at the midplane of a typical patient is approximately 17 and 30 cGy/min using the thick and thin flattening filters, respectively, using the maximum source to couch distance. The maximum useful field size, defined by the 90% isodose line, at this location is 225 × 78 cm with field flatness within 5% over the central 178 × 73 cm. Measured output agreed with external validation within 0.5%. End-to-end testing was performed in a modified Rando phantom. In-house MATLAB software was developed to calculate patient-specific dose distributions using DOSXYZnrc, and fabricate custom 3D-printed forms for creating patient-specific lung blocks. End-to-end OSLD and diode measurements both with and without lung blocks agreed with Monte Carlo calculated doses to within 5% and in-phantom film measurements validated dose distribution uniformity. Custom lung block transmission measurements agree well with design criteria and provide clinically favorable dose distributions within the lungs. Block placement is easily facilitated using the flat panel imaging system with an exposure time of 0.01 min. In conclusion, a novel dedicated TBI unit has been commissioned and clinically implemented. Its mechanical, dosimetric, and imaging capabilities are suitable to provide state-of-the-art TBI for patients as large as 220 cm in height and 78 cm in width.