High dose rate (HDR) brachytherapy technique: For carcinoma of uterine cervix using nucletron applicators

This study describes our existing treatment method for high dose rate (HDR) brachytherapy of carcinoma of uterine cervix using Nucletron applicators. Based on our clinical experience with low dose rate (LDR) brachytherapy since 1986, we deliver 40–45Gy by external and 30Gy by internal radiation therapy. The change in regimen using HDR brachytherapy is that internal radiation dose is given in 5 total of 100 treatments done at our center using ring-tandem (R-T) and ovoid-tandem (O-T) applicator combinations. Since O-T applicator has more flexibility of using desired tandem length and reduced rectum and bladder dose due to internal shielding inside the ovoids, we have made the transition from R-T to O-T combination of applicator. The dose volume histogram of the isodose curve indicates that there is an increase in isodose volume with the O-T applicator by as much as 1.5 times as compared to R-T applicator. In majority of the treatments, rectum and bladder doses are less than 70% of target dose, however in very few treatments, the bladder dose has increased to more than the target dose, in which case, the applicators were reseated and added more packing or reduced the dose per fraction, for better tolerance of late responding normal tissues. All our dose calculations are checked with an independent calculation method and agreement was obtained with in 5–7% discrepancy. From 1991 to January 1995, we have treated over 20 patients and there has been no report of any rectal or bladder complications, while better local control has been reported.     

Standard linear plans in single channel high dose rate brachytherapy: a dosimetric analysis

The use of standard linear plans is proposed for single channel intraluminal High Dose Rate brachytherapy. This technique employs the optimized dwell times derived from a straight line within a curved geometry. Such standardization of the planning procedure ensures expedient delivery of treatment. The 3-D dose distribution resulting from the use of standard linear plans within various curved geometries is investigated. In this study a comparison is made between the dose delivered to the perimeter of the target volume from both standard linear plans and individually optimized plans. Our results demonstrate that the use of a standard linear plan is acceptable in curved geometries, given the current practice of dose and volume specification for high dose rate intraluminal brachytherapy.     

192Ⅰr高剂量率后装治疗剂量准确性的质量控制

目前,192Ⅰr高剂量率后装治疗技术应用越来越广泛.与其他低剂量率放射源相比,用它进行后装治疗时间短、分次剂量高.为确保治疗剂量的准确性,介绍了一些对治疗机位置精度、时间精度和剂量精度进行质量控制的要求和方法.     

A comparison of the expected costs of high dose rate brachytherapy using Cf versus Ir

A cost analysis to compare high dose rate (HDR) brachytherapy using either californium-252 (²⁵²Cf) or ¹⁹²Ir was performed to determine the prospects of widespread clinical implementation of HDR ²⁵²Cf. Interest in the neutron-emitting ²⁵²Cf radioisotope as a radiotherapy nuclide has undergone a resurgence given recent efforts to fabricate HDR remotely afterloaded sources, and other efforts to create a miniature source for improved accessibility to a variety of anatomic sites. Therefore, HDR ²⁵²Cf brachytherapy may prove to be a potential rival to the use of HDR ¹⁹²Ir remotely afterloaded brachytherapy—the current standard-of-care treatment modality using HDR brachytherapy. Considering the possible improvements in clinical efficacy using HDR ²⁵²Cf brachytherapy and the enormous costs of other high-LET radiation sources, the cost differences between ²⁵²Cf and ¹⁹²Ir may be well-justified.     

192Ir高剂量率后装治疗剂量准确性的质量控制

目前,192Ir高剂量率后装治疗技术应用越来越广泛。与其他低剂量率放射源相比,用它进行后装治疗时间短、分次剂量高。为确保治疗剂量的准确性,介绍了一些对治疗机位置精度、时间精度和剂量精度进行质量控制的要求和方法。     

Comparative analysis of rectal dose parameters in image-guided high-dose-rate brachytherapy for cervical cancer with and without a rectal retractor

PurposeThe objective of this study was to determine if use of a rectal retractor (RR) in high-dose-rate intracavitary brachytherapy for cervical cancer reduces rectal dose parameters.Methods and MaterialsWe reviewed data obtained from patients treated with intracavitary brachytherapy for cervical cancer with and without an RR. Treatment plans for each brachytherapy fraction were separated into two groups; R group with use of an RR and P group with use of vaginal packing. Dose–volume parameters for high-risk clinical target volume (HR-CTV), rectum, sigmoid, small bowel, and vaginal surface were collected for each fraction. Rectal D_2cc and International Commission on Radiation Units & Measurements (ICRU) rectal point doses were compared between groups using Student's t tests. Predictors of higher rectal D_2cc were determined by univariate and multivariate regression analyses.ResultsFour hundred sixty-three brachytherapy fractions from 114 patients were used for analysis, 377 fractions with a RR (R group) and 86 with vaginal packing only (P group). Both groups were similar except for slightly higher mean HR-CTV and mean bladder volume in P group. Both mean ICRU rectal point dose (241.1 vs. 269.9 cGy, p = 0.006) and rectal D_2cc (240.6 vs. 283.6 cGy, p < 0.001) were significantly higher in P group. Point A dose, HR-CTV, stage, and use of an RR were significant predictors of rectal D_2cc on multivariate analysis.ConclusionsOur data show that use of an RR leads to lower rectal dose parameters compared with vaginal packing. Further study is needed to determine if this will lead to less long-term toxicity.     

A national surveillance study of the current status of reirradiation using brachytherapy in Japan

PurposeThis study aimed to explore the current status and pattern of practice for reirradiation using brachytherapy (ReRT-BT) through a survey in Japan.Materials and MethodsWe distributed an e-mail-based questionnaire to 153 institutions equipped with high-dose-rate brachytherapy facilities.ResultsWe received responses from 76 institutions (49.7%). Forty-three of these institutions performed ReRT-BT and 42 institutions (55%) performed ReRT-BT during 2009–2018. However, 29 of the 42 institutions (69%) reported difficulty in obtaining ReRT-BT case information from their respective databases. Almost all the institutions encountered insufficient database system to extract details about the ReRT-BT cases. Responses from 33 institutions included the number of ReRT-BT cases; this increased from 90 in the period 2009–2013 (institution median = 0.5; 0–16) to 172 in the period 2014–2018 (institution median = 2; 0–26). Nine institutions had to perform ReRT-BT for more than one case per year. The major location for cancer treatment was the pelvis (94%), followed by the head and neck (5%) and others (1%). In six site-specific scenarios, barring uterine corpus cancer recurrence, more than 90% of radiation oncologists agreed to perform ReRT-BT, whereas other areas (head and neck, prostate, and rectal cancer) gained 16–37% agreement.ConclusionsThis decade saw an increase in the number of ReRT-BT cases in Japan and radiation oncologists’ interest in ReRT-BT as a viable therapeutic option. However, scarce availability, immature education system, and insufficient database system are barriers to further consensus building.     

Quality assurance of HDR prostate plans: Program implementation at a community hospital

Adenocarcinoma of the prostate is currently the most commonly diagnosed cancer in men in the United States, and the second leading cause of cancer mortality. The utilization of radiation therapy is regarded as the definitive local therapy of choice for intermediate- and high-risk disease, in which there is increased risk for extracapsular extension, seminal vesicle invasion, or regional node involvement. High-dose-rate (HDR) brachytherapy is a logical treatment modality to deliver the boost dose to an external beam radiation therapy (EBRT) treatment to increase local control rates. From a treatment perspective, the utilization of a complicated treatment delivery system, the compressed time frame in which the procedure is performed, and the small number of large dose fractions make the implementation of a comprehensive quality assurance (QA) program imperative. One aspect of this program is the QA of the HDR treatment plan. Review of regulatory and medical physics professional publications shows that substantial general guidance is available. We provide some insight to the implementation of an HDR prostate plan program at a community hospital. One aspect addressed is the utilization of the low-dose-rate (LDR) planning system and the use of existing ultrasound image sets to familiarize the radiation therapy team with respect to acceptable HDR implant geometries. Additionally, the use of the LDR treatment planning system provided a means to prospectively determine the relationship between the treated isodose volume and the product of activity and time for the department’s planning protocol prior to the first HDR implant. For the first 12 HDR prostate implants, the root-mean-square (RMS) deviation was 3.05% between the predicted product of activity and time vs. the actual plan values. Retrospective re-evaluation of the actual implant data reduced the RMS deviation to 2.36%.     

Quality assurance of HDR prostate plans: Program implementation at a community hospital

Adenocarcinoma of the prostate is currently the most commonly diagnosed cancer in men in the United States, and the second leading cause of cancer mortality. The utilization of radiation therapy is regarded as the definitive local therapy of choice for intermediate- and high-risk disease, in which there is increased risk for extracapsular extension, seminal vesicle invasion, or regional node involvement. High-dose-rate (HDR) brachytherapy is a logical treatment modality to deliver the boost dose to an external beam radiation therapy (EBRT) treatment to increase local control rates. From a treatment perspective, the utilization of a complicated treatment delivery system, the compressed time frame in which the procedure is performed, and the small number of large dose fractions make the implementation of a comprehensive quality assurance (QA) program imperative. One aspect of this program is the QA of the HDR treatment plan. Review of regulatory and medical physics professional publications shows that substantial general guidance is available. We provide some insight to the implementation of an HDR prostate plan program at a community hospital. One aspect addressed is the utilization of the low-dose-rate (LDR) planning system and the use of existing ultrasound image sets to familiarize the radiation therapy team with respect to acceptable HDR implant geometries. Additionally, the use of the LDR treatment planning system provided a means to prospectively determine the relationship between the treated isodose volume and the product of activity and time for the department’s planning protocol prior to the first HDR implant. For the first 12 HDR prostate implants, the root-mean-square (RMS) deviation was 3.05% between the predicted product of activity and time vs. the actual plan values. Retrospective re-evaluation of the actual implant data reduced the RMS deviation to 2.36%.     

Validation of the NCCN prostate cancer favorable- and unfavorable-intermediate risk groups among men treated with I-125 low dose rate brachytherapy monotherapy

PurposeTo validate the 2019 NCCN subgroups of favorable- and unfavorable-intermediate risk (IR) prostate cancer among patients treated with brachytherapy, who are underrepresented in the studies used to develop the 2019 NCCN classification.MethodsWe included all 2,705 men treated with I-125 LDR brachytherapy monotherapy at a single institution, and who could be classified into the 2019 NCCN risk groups. Biochemical failure and distant metastasis rates were calculated using cumulative incidence analysis.ResultsOf 1,510 IR patients, 756 (50%) were favorable-IR, and 754 (50%) were unfavorable-IR. Median follow up was 48 months (range, 3–214). As compared to favorable-IR, the unfavorable-IR group was associated with significantly higher rates of biochemical failure (HR, 2.87; 95% CI, 2.00–4.10; p < 0.001) and distant metastasis (HR, 3.14; 95% CI, 1.78–5.50, p < 0.001). For favorable-IR vs. unfavorable-IR groups, 5-year estimates of biochemical failure were 4.3% (95% CI, 2.6–6.1%) vs. 17.0% (95% CI, 13.6–20.5%; p < 0.001), and for distant metastasis were 1.6% (95% CI, 0.5–2.6%) vs. 5.4% (95% CI, 3.3–7.4%; p < 0.001), respectively. Patients with one unfavorable-intermediate risk factor (unfavorable-IRF; HR, 2.27; 95% CI, 1.54–3.36; p < 0.001) and 2–3 unfavorable-IRFs (HR, 4.42; 95% CI, 2.89–6.76; p < 0.001) had higher biochemical failure rates; similar findings were observed for distant metastasis (1 unfavorable-IRF: HR, 2.46; 95% CI, 1.34–4.53, p = 0.004; 2–3 unfavorable-IRFs: HR, 4.76; 95% CI, 2.49–9.10, p < 0.001).ConclusionsThese findings validate the prognostic utility of the 2019 NCCN favorable-IR and unfavorable-IR prostate cancer subgroups among men treated with brachytherapy. Androgen deprivation was not beneficial in any subgroup. Alternative treatment intensification strategies for unfavorable-IR patients are warranted.     

Computed tomography-guided interstitial high dose rate brachytherapy for centrally located liver tumours: a single institution study

Objectives

To evaluate the clinical outcome of computed tomography (CT)-guided interstitial (IRT) high-dose-rate (HDR) brachytherapy (BRT) in the treatment of unresectable primary and secondary liver malignancies. This report updates and expands our previously described experience with this treatment technique.

Methods

Forty-one patients with 50 tumours adjacent to the liver hilum and bile duct bifurcation were treated in 59 interventions of CT-guided IRT HDR BRT. The tumours were larger than 4 cm with a median volume of 84 cm³ (38–1,348 cm³). The IRT HDR BRT delivered a median total physical dose of 20.0 Gy (7.0–32.0 Gy) in twice daily fractions of median 7.0 Gy (4.0–10.0 Gy) in 19 patients and in once daily fractions of median 8.0 Gy (7.0–14.0 Gy) in 22 patients.

Results

With a median follow-up of 12.4 months, the local control for metastatic hepatic tumours was 89 %, 73 % and 63 % at 6, 12 and 18 months respectively. The local control for primary hepatic tumours was 90 %, 81 % and 50 % at 6, 12 and 18 months respectively. Severe side effects occurred in 5.0 % of interventions with no treatment-related deaths.

Conclusions

CT-guided IRT HDR BRT is a promising procedure for the radiation treatment of centrally located liver malignancies.

Key points

? Interstitial high-dose-rate brachytherapy (IRT HDR BRT) is a promising treatment for central liver tumours ? CT-guided IRT HDR BRT is safe for treating extensive tumours ? CT-guided IRT HDR BRT could play a role in managing unresectable hepatic malignancies     

Perianal mucinous carcinoma successfully treated with a combination of external beam radiotherapy and high dose rate interstitial brachytherapy

The case of an 84-year-old man with perianal mucinous carcinoma is presented. The tumour was 6 cm in diameter and extended into the surrounding tissues. Taking the patient's advanced age and disease into account, rectosigmoidectomy and colostomy were carried out without resection of most of the tumour. Radiotherapy consisted of pre-operative external beam radiotherapy (EBRT) of 40 Gy in 20 fractions, post-operative EBRT of 24 Gy in 12 fractions, and high dose rate interstitial brachytherapy of 12 Gy in a single fraction. The patient tolerated the entire course of radiotherapy well. The patient is doing well without regrowth or complications 7 years after radiotherapy. To our knowledge, there have been no reports on the successful outcome of radiotherapy for perianal mucinous carcinoma. This case suggests that a combination of EBRT plus interstitial brachytherapy boost may play a role in the definitive treatment of perianal mucinous carcinoma.     

Standard linear plans in single channel high dose rate brachytherapy: a dosimetric analysis

The use of standard linear plans is proposed for single channel intraluminal High Dose Rate brachytherapy. This technique employs the optimized dwell times derived from a straight line within a curved geometry. Such standardization of the planning procedure ensures expedient delivery of treatment. The 3-D dose distribution resulting from the use of standard linear plans within various curved geometries is investigated. In this study a comparison is made between the dose delivered to the perimeter of the target volume from both standard linear plans and individually optimized plans. Our results demonstrate that the use of a standard linear plan is acceptable in curved geometries, given the current practice of dose and volume specification for high dose rate intraluminal brachytherapy.     

Emergency MRI utilization trends at a tertiary care academic medical center: baseline data

RATIONALE AND OBJECTIVES: This study evaluates utilization trends of emergency department (ED)-ordered magnetic resonance imaging (MRI) examinations in an adult academic medical center over a 5-year period (2001-2005). MATERIALS AND METHODS: MRI examinations from the ED-ordering location were identified by searching the radiology information system (RIS). Overall MRI volume and ED patient encounters were also assessed during the same period. Each examination was assessed by type of examination, examination completion time, and primary and secondary clinical indications by reviewing the RIS and medical record. RESULTS: During the study period, 1,900 ED-ordered MRI examinations were performed on 1,020 patients. During the same period, 62,823 total MRI examinations were performed, and the total ED patient volume was 420,840. ED-ordered MRI volume increased 391% over the study period (125 to 614 examinations/year), whereas total MRI volume increased only 38.9% and ED patient volume in our institution actually decreased by -9%. MRI examinations of the brain, magnetic resonance angiography of the head and neck, and spinal MRI were the most commonly ordered tests. Clinical indications were analyzed. Peak times of ED-ordered examination completion were between 4:00 PM and 11:00 PM. A total of 15.5% of examinations required overtime or callback of MRI technologists for completion. CONCLUSIONS: Multiple reasons are suggested that may increase utilization (perceived need for diagnostic certainty, as well as medico-legal and patient-driven factors). Whether this increase in MRI utilization resulted in improved patient outcomes is unclear and should be studied further. Implications for radiologist coverage and resident training are discussed.     

Volume and impact of second-opinion consultations by radiologists at a tertiary care cancer center: data

RATIONALE AND OBJECTIVES: Patients with cancer who are referred to a dedicated oncology center usually have undergone previous imaging studies that the oncologists typically desire to have reviewed by radiologists. Such reinterpretations can be complex and time-consuming, yet many institutions do not systematically account for them as part of the total workload. The purpose of this study was to ascertain the numbers and types of second-opinion consultations performed by radiologists at a tertiary care cancer center, and to assess their effect on work volume. MATERIALS AND METHODS: A survey of referring clinicians was undertaken to evaluate the numbers and types of second-opinion consultations requested of radiologists at the Dana Farber Cancer Institute during a 12-month period. Consultations included review of studies from outside institutions, and cases from Dana Farber in which further comparison was needed. The number of consultations requiring additional tumor size measurements was tallied. The mean daily number of new studies interpreted by radiologists was used as a benchmark of work volume. RESULTS: Radiologists performed 4,664 consultations during 254 workdays, interpreting a mean of 18 additional studies (range, 4-42) per day as a result of referrals for second opinion. These included 3,638 (78%) cross-sectional studies (ie, computed tomographic [CT], magnetic resonance [MR], and ultrasound [US] studies), 674 (14%) mammograms, 220 (5%) plain radiographs, 132 (3%) nuclear medicine scans, and one galactogram. Of the 4,664 consultations, 1,306 (28%) were performed to obtain tumor measurements, many of these involving five to 10 bidimensional calculations per study. A mean of 101 new examinations per day was performed by radiologists during the same 12-month period, including cross-sectional studies (CT and US scans) (56%), plain radiographs (34%), and mammograms (11%). MR imaging was not performed. CONCLUSION: Second-opinion consultations increased the average daily work volume by 18%. This has implications for workforce, as well as for compensation in terms of relative value units and finances for this previously unquantified service.     

Patient-reported outcomes of prostate high-dose-rate brachytherapy boost comparing an outpatient and inpatient protocol: a two-center chronologic cohort study

Purpose

To determine patients’ self-reported experiences of outpatient high-dose-rate prostate brachytherapy boost, and compare with previous cohort treated as inpatients.

Methods and Materials

Using the Prostate Brachytherapy Questionnaire, we previously examined patients’ subjective experience of the brachytherapy procedure when it involved one implant and hospitalization with the template in situ for 2 days (Group 1). The protocol was subsequently changed to two implants, 2 weeks apart as outpatients. Fifty-eight patients treated with the new protocol (Group 2) completed the same questionnaire. We compared the self-reported experiences between Groups 1 and 2 and also between the first and second implant for those in Group 2. Our hypothesis was that the worst rated issues in Group 1 might be reduced with the new approach.

Results

Group 2 patients were less troubled overall by the procedure (mean scores 2.3 vs. 3.2, p = 0.0293). Specifically, they were less troubled by “discomfort” (2.8 vs. 3.8, p = 0.0254); “being stuck in bed” (1.7 vs. 4.2 p < 0.0001); “feeling helpless” (1.3 vs. 2.8, p = 0.0009); “fear of opening my bowels” (2.1 vs. 3.3, p = 0.0055); and “fear of coping with the implant” (1.3 vs. 2.5, p = 0.0004). There was no significant increase in “thought of implant” or “fear of implant” before the second implant. However, more patients rated worse than expected “fear of passing urine” during the second implant.

Conclusions

Patients rated high-dose-rate brachytherapy less troublesome when delivered as outpatient with two implants, 2 weeks apart than as inpatient over 3 days, despite the additional invasive procedure and anesthesia.     

Manual vs. automated implantation of seeds in prostate brachytherapy: Oncologic results from a single-center study

PurposeThe objective of this study was to study survival and tolerance of prostate cancer patients treated with ¹²⁵I permanent interstitial brachytherapy by automated vs. manual implantation of seeds.Methods and MaterialsBetween 2002 and 2010, 349 selected patients were treated with ¹²⁵I brachytherapy by the same team: from 2002 to April 2005, 65 patients with linked seeds and then 284 patients treated using Nucletron First System automated implantation. We analyzed biochemical recurrence-free survival (bRFS) rates and toxicities (univariate and multivariate analyses).ResultsTwo hundred seventy-seven (79.4%) and 69 patients (19.8%) with low- and intermediate-risk disease were treated, respectively (median follow-up: 64 months). The 5-year bRFS rate was 93.1% (95% confidence interval 89.3–95.6) for the entire cohort. The 5-year bRFS rates were 93.4% and 91.7% for patients with low- and intermediate-risk disease, respectively (p = 0.42). In univariate and multivariate analyses, there was no statistically significant difference in the 5-year bRFS rate depending on the implantation technique (93.1% vs. 91.8%, respectively, for automated and linked seeds; p = 0.53). In univariate analysis, only D₉₀ prostate (dose delivered to 90% of the prostate) <140 Gy (p = 0.01), lack of prostate-specific antigen bounce (p = 0.008), and nadir prostate-specific antigen >0.11 (p = 0.01) were predictive factors for bRFS. We observed Grade 3 urethritis in 7 patients (2%), urinary incontinence in 2 patients (0.7%), and Grade 4 proctitis in 2 patients (0.7%).ConclusionsIn this large single-center series, brachytherapy for selected localized prostate cancer achieved excellent rates of biochemical control at 5 years (93.1%) with an acceptable toxicity profile, irrespective of the implantation technique used.