Evaluation of rectal dose discrepancies between planned and in vivo dosimetry using MOSkin detector and PTW 9112 semiconductor probe during 60Co HDR CT-based intracavitary cervix brachytherapy

PurposeDose to the rectum during brachytherapy treatment may differ from an approved treatment plan which can be quantified with in vivo dosimetry (IVD). This study compares the planned with in vivo doses measured with MOSkin and PTW 9112 rectal probe in patients undergoing CT based HDR cervical brachytherapy with Co-60 source.MethodsDose measurement of a standard pear-shaped plan carried out in phantom to verify the MOSkin dose measurement accuracy. With MOSkin attached to the third diode, RP3 of the PTW 9112, both detectors were inserted into patients’ rectum. The RP3 and MOSkin measured doses in 18 sessions as well as the maximum measured doses from PTW 9112, RP_max in 48 sessions were compared to the planned doses.ResultsPercentage dose differences ΔD (%) in phantom study for two MOSkin found to be 2.22 ± 0.07% and 2.5 ± 0.07%. IVD of 18 sessions resulted in ΔD(%) of −16.3% to 14.9% with MOSkin and ΔD(%) of −35.7% to −2.1% with RP3. In 48 sessions, RP_max recorded ΔD(%) of −37.1% to 11.0%. MOSkin_measured doses were higher in 44.4% (8/18) sessions, while RP3_measured were lower than planned doses in all sessions. RP_max_measured were lower in 87.5% of applications (42/47).ConclusionsThe delivered doses proven to deviate from planned doses due to unavoidable shift between imaging and treatment as measured with MOSkin and PTW 9112 detectors. The integration of MOSkin on commercial PTW 9112 surface found to be feasible for rectal dose IVD during cervical HDR ICBT.     

Dosimetric evaluation of image based brachytherapy using tandem ovoid and tandem ring applicators

Aim

The aim of the study is to evaluate the differences in dosimetry between tandem-ovoid and tandem-ring gynaecologic brachytherapy applicators in image based brachytherapy.

Calibration of 192Ir high dose rate brachytherapy source using different calibration procedures

Aim

To calibrate Ir-192 high dose rate (HDR) brachytherapy source using different calibration methods and to determine the accuracy and suitability of each method for routine calibrations.

Background

The source calibration is an essential part of the quality assurance programme for dosimetry of brachytherapy sources. The clinical use of brachytherapy source requires an independent measurement of the air kerma strength according to the recommendations of medical physics societies.

Materials and methods

The Ir-192 HDR brachytherapy source from Gammamed plus machine (Varian Medical Systems, Palo Alto, CA) was calibrated using three different procedures, one using the well-type ionization chamber, second by the in-air calibration method and third using solid water phantoms. The reference air kerma rate (RAKR) of the source was determined using Deutsche Gesellschaft fur Medizinische Physik (DGMP) recommendations.

Results

The RAKR determined using different calibration methods are in good agreement with the manufacturer stated value. The mean percentage variations of 0.21, −0.94, −0.62 and 0.58 in RAKR values with respect to the manufacturer quoted values were observed with the well-type chamber, in-air calibration, cylindrical phantom and slab phantom measurements, respectively.

Conclusion

Measurements with a well-type chamber are relatively simple to perform. For in-air measurements, the indigenously designed calibration jig provides an accurate positioning of the source and chamber with minimum scatter contribution. The slab phantom system has an advantage that no additional phantom and chamber are required other than those used for external beam therapy dosimetry. All the methods of calibration discussed in this study are effective to be used for routine calibration purposes.     

Comparison of manual and inverse optimisation techniques in high dose rate intracavitary brachytherapy of cervical cancer: A dosimetric study

Aims and objectivesTo compare dosimetrically the manual optimisation with IPSA using dose volume histograms (DVH) among patients treated for carcinoma of cervix with intracavitary brachytherapy.BackgroundWith the advent of advanced imaging modalities, there has been a shift from conventional X-ray based planning to three-dimensional planning. Manual optimisation is widely used across various institutions but it is time consuming and operator dependant. Inverse planning simulated annealing (IPSA) is now available in various brachytherapy planning systems. But there is a paucity of studies comparing manual optimisation and IPSA in treatment of carcinoma cervix with intracavitary brachytherapy and hence this study.Materials and methodsFifteen consecutive patients treated between December 2013 and March 2014 with intracavitary brachytherapy for carcinoma of cervix were selected for this study. All patients were initially treated with external beam radiotherapy followed by intracavitary brachytherapy. The DVH was evaluated and compared between manually optimised plans and IPSA in the same set of patients.ResultsThere was a significant improvement in the HRCTV coverage, mean V100 of 87.75% and 82.37% (p = 0.001) and conformity index 0.67 and 0.6 (p = 0.007) for plans generated using IPSA and manual optimisation, respectively. Homogeneity index and dose to the OARs remained similar between the two groups.ConclusionThe use of inverse planning in intracavitary brachytherapy of cervix has shown a significant improvement in the target volume coverage when compared with manual planning.     

Depletion of macrophages and disappearance of postcapillary high endothelial venules in lymph nodes deprived of afferent lymphatic vessels

Summary The afferent lymphatic vessels of rat popliteal lymph nodes were interrupted, and the histological alterations in the lymph nodes occurring 1 to 14 weeks after operation were studied. One week after operation the number of macrophages was considerably reduced and continued to decrease during the subsequent time periods studied. A 6 weeks most macrophages had disappeared. Simultaneously the immunological activity diminished and had completely disappeared 8 weeks after operation. Three weeks after operation the endothelial cells of the postcapillary high endothelial venules had flattened, and the number of immigrating lymphocytes was greatly reduced. Subsequently the lymph nodes became depleted of both macrophages and lymphocytes, leaving only the reticuloendothelial framework.     

Measurement verification of dose distributions in pulsed-dose rate brachytherapy in breast cancer

Aim

The aim of the study was to verify the dose distribution optimisation method in pulsed brachytherapy.

Background

The pulsed-dose rate brachytherapy is a very important method of breast tumour treatment using a standard brachytheraphy equipment. The appropriate dose distribution round an implant is an important issue in treatment planning. Advanced computer systems of treatment planning are equipped with algorithms optimising dose distribution.

Materials and methods

The wax-paraffin phantom was constructed and seven applicators were placed within it. Two treatment plans (non-optimised, optimised) were prepared. The reference points were located at a distance of 5 mm from the applicators’ axis. Thermoluminescent detectors were placed in the phantom at suitable 35 chosen reference points.

Results

The dosimetry verification was carried out in 35 reference points for the plans before and after optimisation. Percentage difference for the plan without optimisation ranged from −8.5% to 1.4% and after optimisation from −8.3% to 0.01%. In 16 reference points, the calculated percentage difference was negative (from −8.5% to 1.3% for the plan without optimisation and from −8.3% to 0.8% for the optimised plan). In the remaining 19 points percentage difference was from 9.1% to 1.4% for the plan without optimisation and from 7.5% to 0.01% for the optimised plan.No statistically significant differences were found between calculated doses and doses measured at reference points in both dose distribution non-optimised treatment plans and optimised treatment plans.

Conclusions

No statistically significant differences were found in dose values at reference points between doses calculated by the treatment planning system and those measured by TLDs. This proves the consistency between the measurements and the calculations.     

Comparison of planned and measured rectal dose in-vivo during high dose rate Cobalt-60 brachytherapy of cervical cancer

Cobalt-60 (Co-60) is a relatively new source for the application of high-dose rate (HDR) brachytherapy. Radiation dose to the rectum is often a limiting factor in achieving the full prescribed dose to the target during brachytherapy of cervical cancer. The aim of this study was to measure radiation doses to the rectum in-vivo during HDR Co-60 brachytherapy. A total of eleven HDR brachytherapy treatments of cervical cancer were recruited in this study. A series of diodes incorporated in a rectal probe was inserted into the patient's rectum during each brachytherapy procedure. Real-time measured rectal doses were compared to calculated doses by the treatment planning system (TPS). The differences between calculated and measured dose ranged from 8.5% to 41.2%. This corresponds to absolute dose differences ranging from 0.3 Gy to 1.5 Gy. A linear relationship was observed between calculated and measured doses with linear regression R² value of 0.88, indicating close association between the measured and calculated doses. In general, absorbed doses for the rectum as calculated by TPS were observed to be higher than the doses measured using the diode probe. In-vivo dosimetry is an important quality assurance method for HDR brachytherapy of cervical cancer. It provides information that can contribute to the reduction of errors and discrepancies in dose delivery. Our study has shown that in-vivo dosimetry is feasible and can be performed to estimate the dose to the rectum during HDR brachytherapy using Co-60.     

The histopathologic evaluation of soft tissue changes in rabbit extremity after different dose-fractionation schemes of interstitial high dose rate (HDR) brachytherapy

Background

The use of HDR in the treatment of soft tissue sarcoma had been on the rise. However, there was limited study to evaluate the effect of different fractionation schemes on soft tissue and the optimal HDR scheme.

Aims

We aimed to assess the histopathologic changes on soft tissue after different HDR brachytherapy doses.

Methods

The subjects were divided into three groups. Each group included 10 limbs. Group A had only an applicator without radiation, group B received a total of 24 Gy at 6 Gy per fraction, twice a day, and group C received a total of 13.5 Gy in a single fraction. The histopathologic findings were grouped into soft tissue pathology-1 (edema, inflammation, endothelial proliferation, necrosis) and soft tissue pathology-2 (atrophy, calcification, vascular hyalinization, fibrosis) (STP-1–2).

Results

The highest mean grade values of STP-1 and STP-2 were observed in group C (0.95 and 1.45) in comparison to group A (0.45 and 0.85) and group B (0.65 and 0.9). The difference in STP-1 was found significant only between groups A and C and the difference in STP-2 was found both between groups A and C and groups B and C.

Conclusion

In our experimental study it was shown that the fractionated interstitial HDR had both lower rate and severity of toxicity in comparison to a single high dose fraction. Before using a single fractionated regimen in the clinic, the increased morbidity related to the irreversible early toxicities or progressive late toxicities should be kept in mind.     

磁共振弥散加权成像在兔良恶性淋巴结鉴别中的价值

目的:采用动物模型研究MR弥散加权成像评价转移性淋巴结与反应增生性淋巴结的价值。方法:24只新西兰兔随机分成两组,分别制作转移性淋巴结与反应增生性淋巴结模型,比较两组淋巴结的表观弥散系数(ADC),同时在DWI图上测量并比较两组淋巴结与肌肉的相对信号强度,并进行病理结果分析。结果:两组淋巴结的DWI相对信号强度无显著性差异(P>0.05)。转移性淋巴结组ADC值大于反应性增生组ADC值,分别为0.82±0.10×10-3mm2/s和1.17±0.14×10-3mm2/s,差异有统计学意义(P<0.05)。结论:MR弥散加权成像ADC值测量有助于转移性淋巴结与反应增生性淋巴结的鉴别     

Development and cell phenotypes in primary follicles of foetal sheep lymph nodes

Lymph nodes from sheep foetuses and postnatal lambs were examined to determine the participation of different leucocyte populations in primary follicle formation, with special emphasis on the emergence and subsequent development of follicular dendritic cells during late gestation and early postnatal life. A series of immune and enzyme histochemical markers was used. The first 5-nucleotidase-positive primary follicles were found at 80 days gestational age (gestation in sheep is 150 days) in superficial cervical lymph nodes. In the last month of gestation the primary follicles possessed follicular dendritic cells, macrophages, dendritic cells, and CD5-positive lymphocytes, in addition to IgM-positive cells. Follicular dendritic cells in primary follicles were found to be ultrastructurally immature. These follicular dendritic cells were characterised by a few, coarse surface projections and many ribosomes attached to the endoplasmic reticulum. A final differentiation to mature follicular dendritic cells was coincident with the postnatal germinal centre reaction. Computer-assisted morphometric analysis demonstrated that the size of 5-nucleotidase-positive primary follicles in the distal jejunal lymph node, but not in the superficial cervical lymph node, increased significantly during late gestation. It was concluded that stromal cells in primary follicles of foetal sheep lymph nodes were a continuously developing population but that ultrastructural maturity was only achieved in the germinal centres of postnatal lambs.     

Lymphocyte subpopulations of regional lymph nodes in human colon and gastric adenocarcinomas

 In order to study the host immune response to tumours, previous knowledge of the cellular composition of regional draining lymph nodes is necessary. Enlarged regional lymph nodes are a common finding in colon and gastric adenocarcinomas. We have studied the cellular composition of normal non-reactive and of regional draining lymph nodes of colon and gastric adenocarcinomas. In normal non-reactive lymph nodes, T lymphocytes (CD2⁺, CD7⁺) constituted the largest fraction of the lymphoreticular cells. These lymphocytes were mainly CD4⁺, and there were more cells expressing the CD45RA isoform of the CD45 antigen than CD45RO. Reactive lymph nodes presented a decreased proportion of CD4⁺ CD45RA⁺ cells and an increased number of B cells. Although most of the T cells in the reactive nodes were CD4⁺ CD45RO⁺, their proportion was similar to that found in normal non-reactive nodes. We studied the presence of the molecules CD28 and CD80 involved in the processes of interaction and activation of T and B lymphocytes. The CD28 molecule was found in all the T lymphocytes, while the CD80 molecule was weakly expressed on the B lymphocyte membrane. Received: 4 January 1996 / Accepted: 28 May 1996     

Long term results of HDR brachytherapy in men older than 75 with localized carcinoma of the prostate

Background

Prostate cancer is an illness with a high incidence, especially among older men. The choice of a treatment option among men above 75 years is, however, not clear. Radical prostatectomy in this age group is connected with a relatively high morbidity. A further possibility of curative treatment is radiotherapy which can be administered in the form of external beam or in combination with high dose rate (HDR) brachytherapy.

Aim

The aim of our work was to evaluate how HDR brachytherapy is tolerated among men older than 75 and how associated diseases can influence the tolerance to this treatment. Of interest to us were the treatment results and mortality from other diseases.

Materials and methods

We analyzed a sample of 20 men above 75 years old (median 77 years) who were undergoing treatment by a combination of external radiotherapy and brachytherapy. Sixteen (80%) of them had prostate cancer with an intermediate and high risk of recurrence, four had low risk prostate cancer. Most patients, 14 (70%), had less than two comorbidities.

Results

The median observation period was 57 months. No perioperative complications were recorded. Acute genitourinary toxicity (GU) to a maximum grade of 1–2 manifested in 60% of cases. Acute gastrointestinal toxicity (GIT) was observed only at grade 1 and in 25% of cases. Late GU toxicity occurred in 35% of patients, with only one showing grade 3; late GIT toxicity was recorded at grade 1 only in 3 patients (15%). 70% of the men lived longer than 3 years after treatment, at present, 50% lived more than 5 years. Long-term biochemical remission was achieved in 18 patients (90%).

Conclusions

HDR BRT is possible and well-tolerated in older men above 75 years in good condition and without serious intercurrence.Well-selected older patients with higher-risk tumours and without serious comorbidities undoubtedly benefit from radical treatment when compared with watchful waiting.     

Radioprotection of eye lens using protective material in neuro cone-beam computed tomography: Estimation of dose reduction rate and image quality

PurposeIn cerebral angiography, for diagnosis and interventional neuroradiology, cone-beam computed tomography (CBCT) scan is frequently performed for evaluating brain parenchyma, cerebral hemorrhage, and cerebral infarction. However, the patient’s eye lens is more frequently exposed to excessive doses in these scans than in the previous angiography and interventional neuroradiology (INR) procedures. Hence, radioprotection for the lenses is needed. This study selects the most suitable eye lens protection material for CBCT from among nine materials by evaluating the dose reduction rate and image quality.MethodsTo determine the dose reduction rate, the lens doses were measured using an anthropomorphic head phantom and a real-time dosimeter. For image quality assessment, the artifact index was calculated based on the pixel value and image noise within various regions of interest in a water phantom.ResultsThe protective materials exhibited dose reduction; however, streak artifacts were observed near the materials. The dose reduction rate and the degree of the artifact varied significantly depending on the protective material. The dose reduction rates were 14.6%, 14.2%, and 26.0% when bismuth shield: normal (bismuth shield in the shape of an eye mask), bismuth shield: separate (two separate bismuth shields), and lead goggles were used, respectively. The “separate” bismuth shield was found to be effective in dose reduction without lowering the image quality.ConclusionWe found that bismuth shields and lead goggles are suitable protective devices for the optimal reduction of lens doses.     

Atrophy of compartments of rat lymph nodes related to an entry of lethally altered lymphocytes

Summary This paper reports the occurrence of an accumulation of lethally altered lymphocytes in the subcapsular sinus of a compartment or compartments of some lymph nodes, an unusual feature best developed in nodes of the mesenteric site in aging athymic animals. Many of these cells are rod-like. In other compartments, similar lymphocytes occurred at various depths in the nodal parenchyma. This was accompanied by the disappearance of a compartment's populations of normal lymphoid cells. The observations reveal that lymphocytes, altered in a tissue, may reach the subcapsular sinus of the draining node compartment and migrate into its parenchyma which then undergoes atrophy. The likely involvement of mast cells is discussed.This work was funded by the Medical Research Council of Canada.     

Lymph flow guided irradiation of regional lymph nodes in patients with cervical cancer: Preliminary analysis of scintigraphic data

PurposeTo evaluate patterns of lymph flow from primary lesions in patients with cervical cancer and to determine how useful for radiotherapy planning this information can be.Materials and methodsSPECT–CT visualization of sentinel (SLN) lymph nodes (LNs) was performed in 36 primary patients with IB-IIB cervical cancer. The acquisition started 120–240 min after 4 peritumoral injections of 99mTc-radiocolloids (150–300 MBq in 0.4–1 ml). We determined localization of LN with uptake of radiocolloids, type of lymph flow (mono-, bi-lateral) and lymph flow patterns (supraureteral paracervical, infraureteral paracervical and directly to para-aortic LNs).ResultsSLNs were visualized in 31 of 36 women. Bilateral lymph-flow was detected in 22 (71%), monolateral – in the other 9 (29%) cases. The distribution of SLNs was as follows: external iliac – 64.5%, internal iliac – 54.8%, obturator – 32.2%, common iliac – 35.5% and pre-sacral 3.2%. Para-aortic LNs were visualized in 5 (16.1%) patients. The supraureteral paracervical pattern of lymph flow was identified in 22, infraureteral paracervical – in 4 and their combination – in the other 5 women.ConclusionVisualization of an individual pattern of lymph flow from primary cervical cancer can be considered as a promising tool for optimization of the volume of irradiated regional LNs.     

VEGF-C和CCR7的表达与卵巢癌淋巴结转移之间的关系

目的观察血管内皮生长因子(VEGF)-C和趋化因子受体CCR7在卵巢癌组织内的表达情况,分析VEGF-C和CCR7的表达与癌淋巴结转移之间的关系。方法取卵巢癌病例72例,其中,淋巴结转移组46例,无淋巴结转移组26例。应用免疫组化技术观察VEGF-C和CCR7在卵巢癌组织内的表达。结果 VEGF-C和CCR7主要表达于卵巢癌细胞胞浆或/和胞膜内,VEGF-C和CCR7在淋巴结转移组的阳性表达率分别是71.7%和78.2%,在无淋巴结转移组的表达率分别是30.8%和26.9%,二者在淋巴结转移组的表达率均明显高于无淋巴结转移组(P<0.01)。VEGF-C和CCR7蛋白同时阳性表达在淋巴结转移组和非淋巴结转移组中的表达率分别为65.2%和15.4%,VEGF-C和CCR7的表达具有显著的相关性(P<0.01),联合检测VEGF-C和CCR7诊断卵巢癌淋巴结转移具有较高的准确度,ROC曲线下面积达0.791。结论 VEGF-C和CCR7表达在卵巢癌淋巴结转移过程中发挥重要作用,VEGF-C和CCR7在促进卵巢癌淋巴结转移中可能具有一定的协同作用,二者联合检测有助于预示卵巢癌淋巴结转移的判断。     

Tissue rinse liquid‐based cytology: a feasible tool for the intraoperative pathological evaluation of sentinel lymph nodes in breast cancer patients

K. Yamashiro, K. Taira, M. Nakajima, D. Okuyama, M. Azuma, H. Takeda, H. Suzuki, H. Jotoku, K. Watanabe, M. Takahashi, K. Taguchi and M. Tamura
Tissue rinse liquid‐based cytology: a feasible tool for the intraoperative pathological evaluation of sentinel lymph nodes in breast cancer patients Objectives: A unique diagnostic method was designed for the intraoperative pathological evaluation of sentinel lymph nodes (SLNs) in breast cancer patients, and the results were verified with 2 years of experience. Methods: Excised lymph nodes were cut into 2‐mm‐thick slices and rinsed thoroughly in CytoRich Red^®. The sliced tissues were embedded in a paraffin block. Three cytological glass slides of the cells exfoliated in CytoRich Red^® were prepared by the SurePath^® liquid‐based cytology (LBC) technique. Two slides were stained by the Papanicolaou method, and the remaining slide was immunostained with an anti‐keratin antibody. This process is called tissue rinse liquid‐based cytology (TRLBC). The results of TRLBC were compared with those of the final pathological diagnoses, including immunostaining with an anti‐keratin antibody on paraffin blocks (PB). Results: This study analysed 444 SLNs from 247 consecutive breast cancer patients. It required 35 minutes to complete the intraoperative diagnosis on a single node, and it took an additional 5 minutes per node if more than one node was submitted. When the results of PB were assumed to be the gold standard, the sensitivity and specificity of TRLBC were 81.9% and 96.1%, respectively. TRLBC detected all nodes with macrometastasis and 23 of 24 nodes with micrometastasis. Fifteen false‐negative TRLBC results were ‘isolated tumour cell clusters’ on PB, but there was one with micrometastasis histologically. Four of 14 false‐positive TRLBC results were proven to be true positive by supplementary examination using step sectioning of the paraffin blocks of the nodes. Conclusion: TRLBC is a feasible and promising intraoperative cytopathological tool showing a comparable efficacy to PB while still allowing the conventional postoperative histological examination.     

Contemporary trends of pelvic lymph node dissection at radical cystectomy for urothelial carcinoma of urinary bladder and associated cancer specific mortality and complications: comparison between octogenarian versus younger patients

BackgroundWe analysed contemporary pelvic lymph node dissection (PLND) trend during radical cystectomy (RC) for urothelial carcinoma of urinary bladder (UCUB), as well as PLND association with cancer specific mortality (CSM) and complications after stratification according to octogenarian vs. younger age.Materials and methodsWithin the SEER and NIS databases, respectively 10,427 (T2 and T3 stages) and 19,203 (all T-stages) RC patients (2004–2015) for UCUB were identified. Univariable and multivariable analyses focused on PLND rates, CSM after inverse probability of treatment weighting (IPTW) adjustment, complication rates, length of stay (LOS) and total hospital charge (THC).ResultsWithin the SEER database, RC and PLND was performed in 9,406 patients (87.4%), 981 (10.4%) octogenarians and 8,227 younger patients (at, respectively, 83 and 89% PLND). PLND rates increased over time in both patients groups (p < 0.05). PLND was independently associated with lower CSM in both age groups (octogenarians: hazard ratio [HR] 0.51, p < 0.001; younger patients: HR 0.56, p < 0.001). Within the NIS database, PLND was marginally higher associated with overall complications in octogenarians than in younger patients (odd ratio [OR]: 1.32 vs. 1.23, both p < 0.001), with longer LOS (OR: 1.20 vs. 1.08, both p < 0.001), higher THC (relative increase: 6933 vs. 4484, both p < 0.001), but not with higher in-hospital mortality.ConclusionsPLND is associated with lower CSM, but its rate lags in octogenarian vs. younger patients. In both age groups, PLND leads to marginally higher complications, longer LOS and higher THC, but not to higher in-hospital mortality.