Brachytherapy technique for abdominal wall metastases of colorectal cancer: ultrasound-guided insertion of applicator needle and a skin preservation method

Purpose: To report a technique of interstitial brachytherapy for the treatment of subcutaneous metastatic abdominal wall tumors.

Material and Methods: We developed a brachytherapy technique consisting of ultrasound-guided insertion of applicator needles to avoid the organs at risk, such as intestines, and saline injection into the subcutaneous tissue between the tumor and the skin to decrease the skin dose. We encountered three patients with painful metastases from rectal carcinoma in the abdominal wall refractory to external radiotherapy. They were subjected to this brachytherapy with a single dose of 20 Gy.

Results: The procedure was safely achieved in all three patients. Long-lasting pain reduction and tumor shrinkage was obtained without early or late complications.

Conclusion: This interstitial brachytherapy technique seems to be feasible in the treatment of metastatic abdominal wall tumors.     

Subcutaneous spacer injection to reduce skin toxicity in breast brachytherapy: A pilot study on mastectomy specimens

Purpose

Accelerated partial breast irradiation is a treatment option for selected patients with early-stage breast cancer. Some accelerated partial breast irradiation techniques lead to skin toxicity with the skin dose as a main risk factor. Biodegradable spacers are effective and safe in prostate brachytherapy to protect the rectum. We hypothesize that a subcutaneous spacer injection reduces the skin dose in breast brachytherapy.

Quality of life after intensity-modulated radiotherapy for prostate cancer with a hydrogel spacer

BACKGROUND: Hydrogel spacer is an innovative method to protect the rectal wall during prostate cancer radiotherapy. Clinical effects are not well known. METHODS: Patients have been surveyed before, at the last day, and 2-3?months after radiotherapy using a validated questionnaire (Expanded Prostate Cancer Index Composite). Median dose to the prostate in the spacer subgroup (SP) was 78?Gy in 2?Gy fractions. The results were independently compared with two matched-pair subgroups (treated conventionally without spacer): 3D conformal 70.2?Gy in 1.8?Gy fractions (3DCRT) and intensity-modulated radiotherapy (IMRT) 76?Gy in 2?Gy fractions. There were 28?patients in each of the three groups. RESULTS: Baseline mean bowel bother scores were 96?points in all subgroups. Similar mean changes (SP 16, 3DCRT 14, IMRT 17 points) were observed at the end of radiotherapy. The smallest difference resulted in the spacer subgroup 2-3?months after radiotherapy (SP 2, 3DCRT 8, IMRT 6 points). Bowel bother scores were only significantly different in comparison to baseline levels in the spacer subgroup. The percentage of patients reporting moderate/big bother with specific symptoms did not increase for any item (urgency, frequency, diarrhoea, incontinence, bloody stools, pain). CONCLUSION: Moderate bowel quality-of-life changes can be expected during radiotherapy irrespective of spacer application or total dose. Advantages with a spacer can be expected a few weeks after treatment.     

放疗在低负荷转移性前列腺癌中的应用价值

目的 探讨不同放疗方法在低负荷转移性前列腺癌（LBMP）中的应用价值。 方法 回顾性分析2009年11月至2015年11月于解放军联勤保障部队第九〇〇医院经组织病理学检查诊断为LBMP的91例男性患者的临床资料,年龄53~72(67.4±4.5)岁。所有患者均接受标准的全雄激素阻断内分泌治疗,其中52例患者接受单纯前列腺直接放疗（PODT组）,39例患者接受前列腺联合转移灶放疗（PMRT组）。PODT组患者的放疗靶区为前列腺和双侧精囊,即计划靶区体积（PTV）,其处方总剂量为62.5 Gy（2.5 Gy/次,1次/d,25次/5周）;PMRT组患者的放疗靶区为PTV+淋巴结计划大体肿瘤体积（PGTV_nd）+椎体转移灶计划大体肿瘤体积（PGTV_m）,其中,PGTV_nd处方总剂量为55 Gy（2.2 Gy/次,1次/d,25次/5周）;PGTV_m处方总剂量为45 Gy（1.8 Gy/次,1次/d,25次/5周）。采用独立样本t检验比较组间肿瘤照射体积、危及器官的照射剂量;采用扩展性前列腺癌复合指数（EPIC）量表和肿瘤放疗协作组（RTOG）标准评价2组患者各个随访时间点的生存质量和急性放射损伤;采用Mann-Whitney U秩和检验比较2组患者的生存质量,采用卡方检验比较急性放射损伤;生存分析采用Kaplan-Meier法,并行Log-rank χ2检验。 结果 PODT组总的照射体积为(264.52±86.37) cm3,显著低于PMRT组的(418.47±63.64) cm3,2组间的差异有统计学意义（t=1.362, P<0.05）。PODT组危及器官（直肠、膀胱、左侧股骨头和右侧股骨头）的照射剂量均显著低于PMRT组（t=2.01~4.78,均P<0.05）。PODT组在放疗结束当天、放疗后3个月、放疗后6个月的泌尿系统功能评分均显著高于PMRT组（Z=4.467、5.726、7.984,均 P<0.05）;PODT组在放疗结束当天、放疗后3个月、放疗后24个月的肠道功能评分均显著高于PMRT组（Z=3.826、5.693、7.874,均 P<0.05）;PMRT组的性功能评分在放疗后3个月及以后的各个随访时间点均高于PODT组（Z=2.381~9.872,均P<0.05）。PODT组和PMRT组的5年总生存（OS）率和前列腺癌特异性生存（PCSS）率的差异均无统计学意义（χ2=4.62、3.07,均P>0.05）。PODT组的5年无生化失败期间（IBF）率低于PMRT组（4.2%对14.9%）,2组间的差异有统计学意义（χ2=7.68,P=0.03）。PMRT组患者白细胞、血小板计数和血红蛋白水平减少、下降的发生率均显著高于PODT组（χ2=6.09、3.12、7.58,均P<0.05）;其呕吐的发生率也显著高于PODT组（48.7%对19.2%,χ2=8.93,P<0.05）。 结论 LBMP患者接受PMRT可提高IBF时间,但无法延长PCSS和OS时间,且增加了辐射损伤的发生率。     

Experiences with a New High-Dose-Rate Brachytherapy (HDR-BT) Boost Technique for T3b Prostate Cancer

PURPOSE: Experiences with a new high-dose-rate brachytherapy (HDR-BT) boost technique in 41 patients with stage T3b prostate cancer are presented. PATIENTS AND METHODS: The patients received 18 Gy of HDR-BT (9 Gy on days 1 + 8) plus 50.4 Gy of EBRT. 20 patients (group A) had BT applicators placed into the prostate alone resulting in 18 Gy to prostate and 0 Gy (tip) to 12 Gy (base) to seminal vesicles (SV). The cumulative EQD2 (equivalent dose in 2-Gy fractions, alpha/beta 1.5 Gy) to the SV was 47.5-73.3 Gy. 21 patients (group B) had BT applicators placed into both prostate and SV resulting in 18 Gy to prostate and to > 80% (but not 100%) of the SV (cumulative EQD2 81.5-101.5 Gy). Both groups were compared for acute and late toxicity and for biochemical relapse-free survival (bRFS). RESULTS: The 3-year bRFS was 57% for group A and 79% for group B patients (p = 0.29). A grade 3 acute toxicity (CTC 2.0) was not observed. Grade 2 acute toxicity (proctitis, cystitis, skin toxicity) was comparable in both groups. A grade 3 late toxicity did not occur. Impotence rates were 35% in group A and 24% in group B, respectively (p = 0.73). CONCLUSION: The new HDR-BT technique (group B) was associated only with minor acute and late toxicity and appears to result in better bRFS than the conventional HDR-BT technique (group A). The results must be confirmed in a prospective trial.     

Assessment of contralateral mammary gland dose in the treatment of breast cancer using accelerated hypofractionated radiotherapy

AIM:To measure the dose distribution,related to the treatment planning calculations,in the contralateral mammary gland of breast cancer patients treated with accelerated hypofractionated 3-dimensional conformal radiotherapy.METHODS:Thirty-four prospectively selected female patients with right breast cancer (pN0,negative surgical margins) were treated with breast-conserving surgery.A total dose of 42.5 Gy (2.66 Gy/fraction) was prescribed;it was requested that planning target volumes be covered by the 95% isodose line.The contralateral mam-mary gland was defined on CT simulation.The dose received was evaluated by dose volume histograms.RESULTS:The measured contralateral breast doses were:(1) Dose maximum:290-448 cGy [Equivalent (Eq) 337-522 cGy];(2) Mean dose:45-70 cGy (Eq 524815 cGy);and (3) Median dose:29-47 cGy (337-547 cGy) for total primary breast dose of 42.5 Gy in 16 equal fractions.The spearman rho correlation showed statistical significance between the contralateral breast volume and maximum dose (P=0.0292),as well as mean dose (P=0.0025) and median dose (P=0.046) to the breast.CONCLUSION:Minimizing the dose to the contralateral breast has to be one of the priorities of the radiation oncologist when using short schedules because of the radiosensitivity of this organ at risk.Further study is necessary to assess the long-term clinical impact of this schedule.     

不同麻醉方式在小儿动脉导管未闭介入治疗中辐射剂量分析

目的：探讨不同麻醉方式在降低小儿动脉导管未闭(PDA)介入治疗中辐射剂量的影响。方法回顾2011—2014年采用2种麻醉方式接受 PDA 介入治疗的小儿(3~6岁)各25例,分为 A、B 2组,A 组为全麻组(男7例,女18例,平均体质量15.32 kg±2.415 kg),B组为局麻组(男13例,女12例,平均体质量16.40 kg±2.056 kg)。2组患者均由相同术者完成手术,采用 DSA 儿童心血管电影自动曝光模式(ped CARD)、摄影帧数15~30 f/s、非离子型对比剂碘克沙醇320 mg I/mL,记录患儿皮肤表面累积入射剂量(AK)、剂量面积乘积(DAP)和透视时间,并作统计学分析。结果50例患儿均顺利完成手术,统计显示,2组患儿的年龄、体质量及性别差异无统计学意义(年龄：t=1.924,P=0.060;体质量：t=1.703,P=0.095;性别：χ2=3.00,P=0.083);全麻组及局麻组辐射剂量 AK、DAP 及透视时间分别为(0.061±0.025)Gy、(0.094±0.046)Gy;(5.08±2.19)Gy·cm2、(8.41±3.587)Gy·cm2;(3.15±1.16)min、(6.86±3.27)min,差异均有统计学意义(AK：t=3.152,P=0.003;DAP：t=3.957,P=0.000;透视时间：t=5.346,P =0.000),2组在采集序列数及图像数相同的基础上,全麻组辐射剂量明显小于局麻组40%[(1-5.08/8.41)%],手术时间相差约1.17倍[(3.15-6.86)/3.15]。结论辐射剂量大小与麻醉方式有关,采用全麻方式进行小儿 PDA 介入治疗较局麻方式辐射剂量明显降低40%。     

Effektivität und Toxizität einer Re-Bestrahlung (Re-RT) bei metastatisch bedingter Rückenmarkkompression (MBRK)

BACKGROUND AND PURPOSE: Radiation myelopathy is a serious late toxicity after radiotherapy (RT) of metastatic spinal cord compression (MSCC). The risk of myelopathy depends on the equivalent dose in 2-Gy fractions (EQD2). Many radiation oncologists are concerned about spinal Re-RT, because it may result in a high cumulative EQD2. This study investigates effectiveness and feasibility of Re-RT for in-field recurrence of MSCC. PATIENTS AND METHODS: 74 patients, irradiated between 01/1995 and 12/2003 for MSCC, were reirradiated for in-field recurrence of MSCC (Table 1). Primary RT was performed with 1 x 8 Gy (n = 34), 5 x 4 Gy (n = 28), 10 x 3 Gy (n = 4), 15 x 2.5 Gy (n = 4), or 20 x 2 Gy (n = 4). Recurrence occurred after median 6 months (2-40 months). Re-RT was performed with 1 x 8 Gy (n = 35), 5 x 3 Gy (n = 16), 5 x 4 Gy (n = 13), 10 x 2 Gy (n = 4), 12 x 2 Gy (n = 3), or 17 x 1.8 Gy (n = 3). Cumulative EQD2 (alpha/beta = 2 Gy) was 39-40 Gy (n = 21), 49-50 Gy (n = 41), 56-60 Gy (n = 6), or > 60 Gy (n = 6). Follow-up after Re-RT was median 9 months (2-52 months). RESULTS: Re-RT led to an improvement of motor function in 29/74 patients (39%; Figures 1 to 3). On multivariate analysis, outcome was significantly influenced by type of primary tumor (p = 0.013) and by the time of developing motor deficits before Re-RT (p = 0.037), but not by radiation schedule (p = 0.560), by ambulatory status before Re-RT (p = 0.471), by cumulative EQD2 (p = 0.795), nor by the interval between primary RT and Re-RT (p = 0.420; Table 2). Radiation myelopathy was not observed in the whole series. CONCLUSION: Re-RT is an effective treatment for an in-field recurrence of MSCC. After a cumulative EQD2 < or = 50 Gy, radiation myelopathy appears unlikely.     

Magnetic resonance-guided biopsy of suspicious breast lesions with a handheld vacuum biopsy device

Purpose: To evaluate a handheld vacuum-assisted device system for magnetic resonance image (MRI)-guided breast lesion biopsy.

Material and Methods: In 32 patients, a total of 42 suspicious breast lesions (mean diameter 7.5 mm for mass lesions, 11.6 mm for non-masslike diffuse lesions) seen with MRI (no suspicious changes in breast ultrasound or mammography) were biopsied (27 lateral, 15 medial) using a 10G vacuum-assisted breast biopsy device under MR guidance. Histology of biopsy specimens was compared with final histology after surgery or follow-up in benign lesions.

Results: In all biopsies, technical success was achieved. Histology revealed 11 lesions with ductal carcinoma in situ (DCIS) or invasive cancer, three with intermediate lesions (LCIS) and 28 with benign breast lesions (adenosis, infected hematoma). In one patient with discordant results of MRI and histology, surgical excision revealed medullary cancer. In the follow-up (mean 18 months) of the histological benign lesions, no breast cancer development was observed. Besides minor complications (hematoma, n = 6), with no further therapeutic interventions, no complications occurred.

Conclusion: MRI-guided breast lesion biopsy using a handheld vacuum-assisted device is a safe and effective method for the work-up of suspicious lesions seen with breast MRI without changes in mammography or ultrasound. In the case of discordant histology of vacuum biopsy and breast MRI appearance, surgical excision is recommended.     

Ultrasound-guided core needle biopsy of non-palpable breast lesions: a prospective analysis in 204 cases

Purpose: To assess the diagnostic value of ultrasound (US)-guided 14 G core needle breast biopsy in non-palpable suspicious breast lesions.

Material and Methods: From August 1997 to April 2001, 198 patients with 204 suspicious non-palpable breast lesions underwent US-guided large core needle biopsy. Biopsies were performed with a free-hand technique using US equipment with a 7.5 MHz linear-array transducer; a minimum of three cores were obtained from each lesion. Pathological findings in US-guided core biopsy were correlated to findings in subsequent surgery or long-term (more than 2 years) imaging follow-up.

Results: Among the 204 non-palpable breast lesions for which histopathological findings were obtained by US-guided core biopsy, 118 were malignant (114 carcinoma, 2 metastasis, 1 lymphoma, and 1 malignant phyllodes tumor) and 86 were benign (4 carcinoma and 82 benign lesions confirmed at surgery or after at least 2 years of follow-up). Sensitivity, specificity, positive predictive value, and negative predictive value for diagnosis of malignancy in our series were 97%, 100%, 100%, and 95%, respectively. Diagnostic yield with 1, 2, 3, and 4 specimens per lesion was 73.5%, 88%, 94%, and 97.5%, respectively.

Conclusion: US-guided core needle biopsy is a sensitive percutaneous biopsy method for diagnosing non-palpable breast lesions. To achieve a high diagnostic yield, a minimum number of three cores per lesion is advisable.     

湿润烧伤膏联合龙血竭防治乳腺癌改良根治术后放射性皮肤损伤疗效观察

目的对比分析湿润烧伤膏联合龙血竭防治乳腺癌改良根治术后放射性皮肤损伤的临床疗效。方法将2015年8月至2018年8月临沂市第三人民医院收治的120例乳腺癌改良根治术后行放射治疗的患者按照治疗方法分为观察组(60例)、对照1组(30例)与对照2组(30例),观察组患者放射治疗后照射区域皮肤均匀涂抹湿润烧伤膏,出现Ⅱ~Ⅳ级放射性皮肤损伤时加用龙血竭粉末外敷;对照1组患者放射治疗后照射区域皮肤均匀涂抹湿润烧伤膏,出现Ⅱ~Ⅳ级放射性皮肤损伤时继续应用湿润烧伤膏换药治疗;对照2组患者放射治疗后照射区域皮肤不采取防护措施,出现Ⅱ~Ⅳ级放射性皮肤损伤时予以碘伏常规换药治疗。对比观察3组患者放射性皮肤损伤发生情况、放射治疗中断情况及临床疗效结果放射治疗20 Gy、40 Gy及结束后,3组患者皮肤损伤发生情况对比,χ~2=59.417、94.876、29.072,P均=0.000,差异具有统计学意义,且对照2组患者皮肤损伤发生情况较观察组及对照1组严重(放射治疗20Gy后:χ~2=41.918、23.721,P均=0.000;放射治疗40 Gy后:χ~2=74.118、47.368,P均=0.000;放射治疗结束后:χ~2=61.606、30.610,P均=0.000),而观察组与对照1组患者皮肤损伤发生情况无明显差异(P均>0.05)。放射治疗过程中,对照2组中有7例患者因放射性皮肤损伤中断治疗,明显高于观察组与对照1组均无患者中断治疗(χ~2=15.181、7.925,P=0.000、0.005)。放射治疗结束后2周,观察组患者的临床疗效明显优于对照1组及对照2组(χ~2=6.923、24.761,P=0.009、0.000),而对照1组患者的临床疗效明显优于对照2组(χ~2=8.324,P=0.016)。结论湿润烧伤膏联合龙血竭可有效防治乳腺癌改良根治术后放射性皮肤损伤,促进放射性皮肤损伤创面愈合,避免放射治疗中断,且操作简便,值得临床推广应用。     

内镜下钛夹植入对局部晚期食管癌术前放疗患者靶区勾画和剂量学参数的影响

目的:探讨内镜下钛夹植入对局部晚期食管癌术前放疗患者靶区勾画和剂量学参数的影响。方法:回顾性分析2018年1月至2019年12月于联勤保障部队第九〇〇医院经超声胃镜及组织病理学检查确诊为局部晚期食管鳞癌的36例患者的临床资料,其中男性23例、女性13例,年龄18~65 (43.7±6.9）岁。放疗前所有患者均在内镜下分...     

A skin dose prediction model based on in vivo dosimetry and ultrasound skin bridge measurements during intraoperative breast radiation therapy

PurposeUsing in vivo measurements from optically stimulated luminescence dosimeters (OSLDs) to develop and validate a prediction model for estimating the skin dose received by patients undergoing breast intraoperative radiation therapy (IORT).Methods and MaterialsIORT was performed using INTRABEAM-600 with spherical applicators placed in the lumpectomy cavity. Ultrasound skin bridge measurements were used to determine the applicator-to-skin distance, with OSLDs placed to measure the skin surface dose at the corresponding points. The OSLD response was calibrated for the 50 kVp INTRABEAM-600 output. Models were fit to describe the dose fall-off with increasing applicator-to-skin distance and the best fitting model was chosen for estimating skin dose.ResultsTwenty four patients with 25 lumpectomy cavities were included, and the average skin dose recorded was 1.18 Gy ± 0.88 Gy, ranging from 0.17 Gy to 4.77 Gy, with an average applicator-to-skin distance of 19.9 mm ± 5.1 mm. An exponential-plateau model was found to best describe the dose fall-off with a root-mean-square error of 0.73. This model was then validated prospectively using skin dose measurements from five consecutive patients. Validation measurements were well within the 95% prediction limits of the model, with a root-mean-square error of 0.52, showing that the prediction model accurately estimates skin dose using ultrasound skin bridge measurements.ConclusionsThis prediction model constitutes a useful tool for estimating the skin dose received during breast lumpectomy IORT. The model and accompanying 95% confidence intervals can be used to establish a minimum allowable skin bridge distance, effectively limiting the maximum allowable skin dose.     

Accelerated Partial-Breast Irradiation with Interstitial Implants

PURPOSE: To describe relative skin dose estimations and their impact on cosmetic outcome in interstitial multicatheter accelerated partial-breast irradiation (APBI). PATIENTS AND METHODS: Between April 2001 and January 2005, 105 consecutive patients with early breast cancer were recruited in Erlangen, Germany, for this substudy of the German-Austrian APBI phase II trial. 51% (54/105) received pulsed-dose-rate (PDR), and 49% (51/105) high-dose-rate (HDR) brachytherapy. Prescribed reference dose for HDR brachytherapy was 32 Gy in eight fractions of 4 Gy, twice daily. Prescribed reference dose in PDR brachytherapy was 49.8 Gy in 83 consecutive fractions of 0.6 Gy every hour. Total treatment time was 3-4 days. With a wire cross on the skin surface during the brachytherapy-planning procedure the minimal, mean and maximal relative skin doses (SD(min%), SD(max%), SD(mean%)) were recorded. Endpoint of this evaluation was the cosmetic outcome in relation to the relative skin doses. RESULTS: Median follow-up time was 38 months (range, 19-65 months). Cosmetic results for all patients were excellent in 57% (60/105), good in 36% (38/105), and fair in 7% (7/105). The SD(min%) (27.0% vs. 31.7%; p = 0.032), SD(mean%) (34.2% vs. 38.1%; p = 0.008), and SD(max%) (38.2% vs. 46.4%; p = 0.003) were significantly lower for patients with excellent cosmetic outcome compared to patients with a suboptimal outcome. SD(mean%) (37.6% vs. 34.2%; p = 0.026) and SD(max%) (45.4% vs. 38.2%; p = 0.008) were significantly higher for patients with good cosmetic outcome compared with the patients with excellent results. CONCLUSION: The appraisal of skin doses has been shown to be relevant to the achievement of excellent cosmetic outcome. Further investigations are necessary, especially on the basis of CT-based brachytherapy planning, to further improve the treatment results of multicatheter APBI.     

3D-TPS计算 125I放射性粒子链径向剂量分布的实验研究

目的：应用计算机三维治疗计划系统（3D-TPS）计算不同长度、不同距离、不同活度下¹²⁵I放射性粒子链的表面径向剂量分布。 方法：将预制的单、双、三粒子链置入人体等效体膜内后进行CT扫描,将扫描图像传入治疗计划系统,制作验证计划,计算粒子链的表面径向剂量分布。 结果：¹²⁵I粒子链的剂量场为圆柱形,剂量距离中心1 cm以上,剂量跌落快,径向累积剂量（dose,Gy）与放射性粒子活度（activity,mCi）和测量点距离中心的距离（distance,cm）的回归方程分别为单链：ln dose=43.3 activity-24.2 distance+48.4;双链：ln dose=95.4 activity-55.8 distance+112.0;三链ln dose=138.0 activity-79.8 distance+160.5。 结论：¹²⁵I粒子链的剂量场为圆柱型,粒子链剂量主要受粒子活度和距离中心的径向距离变化影响,粒子链的长度影响微弱。本测量结果可为临床应用提供剂量学参考。     

Is stereotactic CyberKnife radiotherapy or multicatheter HDR brachytherapy the better option dosimetrically for accelerated partial breast irradiation?

ObjectiveTo compare dosimetrically the stereotactic CyberKnife (CK) therapy and multicatheter high-dose-rate (HDR) brachytherapy (BT) for accelerated partial breast irradiation (APBI).MethodsTreatment plans of 25 patients treated with CK were selected, and additional plans using multicatheter HDR BT were created on the same CT images. The prescribed dose was 6.25/25 Gy in both plans to the target volume (PTV). The dose-volume parameters were calculated for both techniques and compared.ResultsThe D90 total dose of the PTV was significantly lower with CK than with HDR BT, D90 was 25.7 Gy, and 27.0 Gy (p < 0.001). However, CK plans were more conformal than BT, COIN was 0.87, and 0.81 (p = 0.0030). The V50 of the non-target breast was higher with CK than with BT: 10.5% and 3.3% (p = 0.0010), while there was no difference in the dose of the contralateral breast and contralateral lung. Dose to skin, ipsilateral lung, and ribs were higher with CK than with BT: D₁ was 20.6 Gy vs. 11.5 Gy (p = 0.0018) to skin, 11.4 Gy vs. 9.6 Gy (p = 0.0272) to ipsilateral lung and 18.5 Gy vs. 12.3 Gy (p = 0.0013) to ribs, while D_0.1 to heart was lower, 3.0 Gy vs. 3.2 Gy (p = 0.0476), respectively.ConclusionsMulticatheter HDR BT yields more advantageous plans than stereotactic CyberKnife treatment in accelerated partial breast irradiation, except in terms of dose conformality and the dose to the heart. There was no difference in the dose of the contralateral breast and lung.     

Assessment of organ radiation dose associated with uterine artery embolization

Purpose: To evaluate the radiation dose to the skin, uterus, and ovaries during uterine artery embolization.

Material and Methods: Guided uterine artery embolization for leiomyomata and two types of X-ray equipment with different dose levels were utilized during fluoroscopy in 20 women (ages ranging from 32 to 52 years, body weights from 55 to 68 kg). The first 13 women were treated using a non-pulsed system A, with 3.3 mm Al filtering and, for simplicity, a fixed peak voltage 80 kV. During treatment of the other 7 women, a pulsed system B with 5.4 mm Al filtering and an identical fixed voltage was used. The dose area product (DAP) was recorded. The vaginal dose of the first 13 patients and the peak skin dose of all patients were measured with thermoluminescent dosimeters (TLDs). TLDs were placed in the posterior vaginal fornix and on the skin at the beam entrance site. The uterine and ovarian doses were estimated based on the measured skin doses, normalized depth dose, and organ depth values. The effective dose (D_eff) was estimated based on the observed DAP values. The measured vaginal doses and the corresponding estimated uterine doses were compared statistically, as were the DAP values from systems A and B.

Results: For system A, the mean fluoroscopic time was 20.9 min (range 12.7-31.1), and for system B 35.9 min (range 16.4-55.4). The mean numbers of angiographic exposures for systems A and B were 82 (range 30-164) and 37 (range 20-72), respectively. The mean peak skin dose for system A was 601.5 mGy (range 279-1030) and for system B 453 mGy (range 257-875). The mean DAP for system A was 88.6 Gy·cm² (range 41.4-161.0) and for system B 52.5 Gy·cm² (range 20.1-107.9). Statistical analysis showed a significant difference between the DAP values, the DAP for system B being the lower one. The mean estimated effective doses from systems A and B were 32 mSv (range 15.1-58.4) and 22 mSv (range 9-46), respectively. The mean estimated maximum uterine and ovarian doses using system A were 81 mGy (range 30-247) and 85 mGy (range 24-207), respectively; when using system B, the respective doses were 101 mGy (range 45-182) and 105 mGy (range 31-246). The measured vaginal doses had a mean value of 52.5 mGy (range 12-124). Statistical analysis revealed a significant difference between the estimated uterine doses and the measured vaginal doses.

Conclusion: A significant difference was found between the estimated uterine doses and the corresponding measured vaginal doses. This has to be kept in mind when using vaginal doses as a substitute for the uterine dose. There was also a significant difference between the DAP values from systems A and B. System B, with pulsed fluoroscopy and greater filtration, gave the lower exposure. The maximum skin dose indicates that skin injuries are unlikely to occur. The ovarian doses are also below the threshold for temporary or permanent sterility. The stochastic risk for radiation-induced cancer and genetic injury to the patient's future children is not considered as substantial.     

Optimization of beam orientations and weights for coplanar conformal beams in treating pancreatic cancer

In treating pancreatic cancer with external-beam radiotherapy, radiation dose given to the tumor volume is largely limited by the tolerance of the normal structures near the disease site, including the kidneys, liver, stomach, small bowel, and spinal cord. The purpose of this work was to investigate whether a coplanar conformal therapy technique with beam optimization could reduce dose to the normal tissues compared to the conventional 4-field technique; and if this was true, whether other beam arrangements were more effective than the 4-field technique in treating pancreatic cancer. In this study, 9 patients who were treated previously for T₃N₀ or T₃N₁ pancreatic cancer with external-beam therapy of 30 Gy in 10 fractions were selected. Beam orientations and weights were optimized for 4 to 6 coplanar conformal beams using a simulated annealing algorithm to minimize the kidney volume receiving more than 20 Gy. Optimized plans were compared with standard plans using a 4-field technique with respect to the isodose distributions and dose volume histograms. For the standard 4-field plans giving 30 Gy to the tumor volume, the total kidney volume above 20 Gy ranged from 10% to 35%, with a mean of 22% and a standard deviation of 7%. Optimization of the beam orientations and weights reduced this volume by approximately 2 times without a significant increase of dose to the liver, stomach, and small bowel. This indicated that the radiation toxicity to the kidneys could be reduced substantially by a careful selection of oblique beam angles and weights. Analysis of the optimized plans showed that beam arrangements which involved left and right anterior oblique beams were superior to the conventional 4-field technique for reducing the kidney dose in treating pancreatic cancer.     

Automatic image quality quantification and mapping with an edge-preserving mask-filtering algorithm

Background: Imaging modalities in digital radiology produce large amounts of data for which image quality should be determined in order to validate the diagnostic operation.

Purpose: To develop an automatic method for image quality assessment.

Material and Methods: A filtering algorithm using a moving square mask was applied to create a map of filtered local intensity and noise values. Image quality scores were calculated from the filtered image data. The procedure was applied to technical and anthropomorphic (radiosurgery verification phantom [RSVP] head) phantom images obtained with varying radiation dose, field of view (FOV), and image content. The method was also applied to a clinical computed tomography (CT) brain image.

Results: The image quality score (IQs) of the phantom images increased from 0.51 to 0.82 as the radiation dose (CTDI_vol) increased from 9.2 to 74.3 mGy. Correlation of the IQs with the pixel noise was R² = 0.99. The deviation (1 SD) of IQs was 2.8% when the reconstruction FOV was set between 21 and 25 cm. The correlation of IQs with the pixel noise was R² = 0.98 with variable image contents and dose. Automatic tube current modulation applied to the RSVP phantom scan reduced the variation in the calculated image quality score by about 60% compared to the use of a fixed tube current.

Conclusion: The image quality score provides an efficient tool for automatic quantification of image quality. The presented method also produces a 2D image quality map, which can be used for further image analysis.     

Long-term results of pulsed irradiation of skin metastases from breast cancer. Effectiveness and sequelae.

PURPOSE: The concept of pulsed brachytherapy suggested by Brenner and Hall requires an unusual fractionation scheme. Effectiveness and sequelae of this new irradiation method were observed in patients with disseminated cutaneous metastases of breast cancer. PATIENTS AND METHODS: A flexible, reusable skin mold (weight 110 g) was developed for use with a pulsed dose rate (PDR) afterloader. An array of 18 parallel catheters (2 mm diameter) at equal distances of 10 or 12 mm was constructed by fixation of the catheters in a plastic wire mesh. The array is sewn between 2 foam rubber slabs of 5 mm thickness to provide a defined constant distance to the skin. Irradiations are possible up to a maximum field size of 20 x 23.5 cm using a nominal 37 GBq Ir-192 source. Pulses of 1 Gy reference dose at the skin surface are applied at a rate of 1 pulse every 1.2 hours (0.8 Gy per hour). The dose distribution is geometrically optimized to provide a homogeneous skin dose (100% +/- 10%). The 80% dose level lies at 5 mm below the skin surface. Between April 1994 and December 1997, 52 patients suffering from cutaneous metastases at the thoracic wall were treated with 54 fields and total doses of 38 to 50 Gy (median 42 Gy) applying 2 PDR courses with a pause of 4 to 5 weeks. RESULTS: Forty-six patients (48 fields) were eligible for evaluation in June 1998. The median follow-up was 16 months (range 7.1 to 46.2 months). Local control was achieved in 40 out of 48 fields (83%) or 41 of 46 patients (89%), respectively. Moist desquamation occurred in 52% of the patients. Late reactions were judged after a minimum follow-up of 6 months. Thirty-two fields had been previously irradiated with external beam therapy to doses of 40 to 60 Gy. Regardless of whether the skin was preirradiated or not all patients surviving long enough developed telangiectasia within 2 years after PDR irradiation. In preirradiated patients (n = 32) skin contractures and/or skin necrosis occurred in 12% each. In newly irradiated patients (n = 14) no contractures or skin necrosis were observed. CONCLUSIONS: Pulsed brachytherapy is an effective and time-sparing method for the treatment of cutaneous metastases from breast cancer. Skin reactions are comparable to the sequelae of orthovoltage therapy. Two sessions of approximately 20 Gy PDR were tolerated on preirradiated skin without severe sequelae.