低剂量CT在肺癌术后短期复查中的应用价值

  目的   通过常规CT和低剂量CT的对比研究,探讨低剂量CT在肺癌术后短期复查中的应用价值。   方法   83例肺癌术后短期内复查CT的患者,50例（A组）行常规CT扫描,33例（B组）行低剂量CT扫描。分别从图像质量和临床需求角度出发对所有CT图像进行评分,并记录每个病例的辐射剂量指标CTDIvol、DLP。比较二组之间的评分和辐射剂量是否存在显著性差异。   结果   二组在图像质量方面的平均得分分别为3.705±0.314、3.311±0.442,在临床需求方面的平均得分为2.670±0.373、2.561±0.410,CTDIvol分别为（19.248±1.532）mGy、（10.138±1.113）mGy,DLP分别为（170.180±19.259）mGy*cm、（99.061±14.504）mGy*cm。二组在图像质量、CTDIvol、DLP方面均存在显著性差异,在临床需求评分方面无显著性差异。   结论   低剂量CT完全能满足临床对于肺癌术后短期复查的需求,并明显降低了辐射剂量。      

Ergebnisse der Österreichischen CT-Dosisstudie 2010: Effektive Dosen der häufigsten CT-Untersuchungen und Unterschiede zwischen Anwendern

PurposeTo determine typical doses from common CT examinations of standard sized adult patients and their variability between CT operators for common CT indications.Materials and MethodsIn a nationwide Austrian CT dose survey doses from approx. 10,000 common CT examinations of adults during 2009 and 2010 were collected and ?typical“ radiation doses to the “average patient”, which turned out to have 75.6 kg body mass, calculated. Conversion coefficients from DLP to effective dose were determined and effective doses calculated according to ICRP 103. Variations of typically applied doses to the “average patient” were expressed as ratios between 90^th and 10^th percentile (inter-percentile width, IPW90/10), 1^st and 3^rd quartile (IPW75/25), and Maximum/Minimum.ResultsMedian effective doses to the average patients for standard head and neck scans were 1.8 mSv (cervical spine), 1.9 mSv (brain: trauma/bleeding, stroke) to 2.2 mSv (brain: masses) with typical variation between facilities of a factor 2.5 (IPW90/10) and 1.7 (IPW75/25). In the thorax region doses were 6.4 to 6.8 mSv (pulmonary embolism, pneumonia and inflammation, oncologic scans), the variation between facilities was by a factor of 2.1 (IPW90/10) and 1.5 (IPW75/25), respectively. In the abdominal region median effective doses from 6.5 mSv (kidney stone search) to 22 mSv (liver lesions) were found (acute abdomen, staging/metastases, lumbar spine: 9-12 mSv; oncologic abdomen plus chest 16 mSv; renal tumor 20 mSv). Variation factors between facilities were on average for abdominal scans 2.7 (IPW90/10) and 1.8 (IPW75/25).ConclusionVariations between CT operators are generally moderate for most operators, but in some indications the ratio between the minimum and the maximum of average dose to the typical standard patients exceeds a factor of 4 or even 5. Therefore, comparing average doses to Diagnostic Reference Levels (DRLs) and optimizing protocols need to be encouraged.     

Significantly Low Effective Dose from 18FDG PET/CT Scans Using Dose Reducing Strategies: "Lesser is Better"

Background: Fluorodeoxyglucose (18FDG) PET/CT imaging has become an important component of the management paradigm in oncology. However, the significant imparted radiation exposure is a matter of growing concern especially in younger populations who have better odds of survival. The aim of this study was to estimate the effective dose received by patients having whole body 18FFDG PET/CT scanning as per recent dose reducing guidelines at a tertiary care hospital. Materials and Methods: This prospective study covered 63 patients with different cancers who were referred for PET/CT study for various indications. Patients were prepared as per departmental protocol and 18FDG was injected at 3 MBq/Kg and a low dose, nonenhanced CT protocol (LD NECT) was used. Diagnostic CT studies of specific regions were subsequently performed if required. Effective dose imparted by 18FDG (internal exposure) was calculated by using multiplying injected dose in MBq with coefficient 1.9?102 mSv/MBq according to ICRP publication 106. Effective dose imparted by CT was calculated by multiplying DLP (mGy.cm) with ICRP conversion coefficient "k" 0.015 [mSv / (mG. cm)]. Results: Mean age of patients was 49 18 years with a male to female ratio of 35:28 (56%:44%). Median dose of 18FDG given was 194 MBq (range: 139293). Median CTDIvol was 3.25 (2.46.2) and median DLP was 334.95 (246.70 576.70). Estimated median effective dose imparted by 18FDG was 3.69 mSv (range: 2.855.57). Similarly the estimated median effective dose by low dose (nondiagnostic) CT examination was 4.93 mSv (range: 2.14 10.49). Median total effective dose by whole body 18FDG PET plus low dose nondiagnostic CT study was 8.85 mSv (range: 5.5613.00). Conclusions: We conclude that the median effective dose from a whole body 18FDG PET/CT in our patients was significantly low. We suggest adhering to recently published dose reducing strategies, use of ToF scanner with CT dose reducing option to achieve the lower if not the lowest effective dose. This would certainly reduce the risk of second primary malignancy in younger patients with higher odds of cure from first primary cancer.     

Percutaneous CT-guided radiofrequency ablation for patients with extrahepatic oligometastases of hepatocellular carcinoma: long-term results

Background: The aim of this study was to evaluate the therapeutic outcome of percutaneous computed tomography (CT)-guided radiofrequency ablation (RFA) for extrahepatic oligometastases of hepatocellular carcinoma (HCC).

Methods: Institutional review board approval was obtained for this retrospective study, and all patients provided written informed consent. Between April 2004 and December 2015, 116 oligometastases (diameter, 5–50?mm; 20.3?±?10.4) in 79 consecutive HCC patients (73 men and 6 women; average age, 50.3?years ±13.0) were treated with RFA. We focussed on patients with 1–3 extrahepatic metastases (EHM) confined to 1–2 organs (including the lung, adrenal gland, bone, lymph node and pleura/peritoneum) who were treated naïve with curative intent. Survival, technical success and safety were evaluated. The log-rank test and Cox proportional hazards regression models were used to analyse the survival data.

Results: No immediate technical failure occurred, and at 1 month, the technique effectiveness rate was determined to be 95.8%. After a median follow-up time of 28.0 months (range, 6–108 months), the 1-, 2- and 3-year overall survival (OS) rates were 91, 70 and 48%, respectively, with a median survival time of 33.5 months. Time to unoligometastatic progression (TTUP) of less than 6 months (p?p?=?0.001) were significant indicators of shorter OS. The 1-, 2- and 3-year disease free survival (DFS) rates were 34, 21 and 8%, respectively, with a median DFS time of 6.8 months. DFS was better for those with lung metastases (p?=?0.006). Major complication occurred in nine (9.5%, 9/95) RFA sessions without treatment-related mortality.

Conclusions: CT-guided RFA for oligometastatic HCC may provide favourable efficacy and technical success with a minimally invasive approach.     

Ablation therapy of non-colorectal cancer lung metastases: retrospective analysis of tumour response post-laser-induced interstitial thermotherapy (LITT), radiofrequency ablation (RFA) and microwave ablation (MWA)

Purpose: To retrospectively compare the local tumour response and survival rates in patients with non-colorectal cancer lung metastases post-ablation therapy using laser-induced thermotherapy (LITT), radiofrequency ablation (RFA) and microwave ablation (MWA).

Material and methods: Retrospective analysis of 175 computed tomography (CT)-guided ablation sessions performed on 109 patients (43 males and 66 females, mean age: 56.6 years). Seventeen patients with 22 lesions underwent LITT treatment (tumour size: 1.2–4.8?cm), 29 patients with 49 lesions underwent RFA (tumour size: 0.8–4.5?cm) and 63 patients with 104 lesions underwent MWA treatment (tumour size: 0.6–5?cm). CT scans were performed 24-h post-therapy and on follow-up at 3, 6, 12, 18 and 24 months.

Results: The overall-survival rates at 1-, 2-, 3- and 4-year were 93.8, 56.3, 50.0 and 31.3% for patients treated with LITT; 81.5, 50.0, 45.5 and 24.2% for patients treated with RFA and 97.6, 79.9, 62.3 and 45.4% for patients treated with MWA, respectively. The mean survival time was 34.14 months for MWA, 34.79 months for RFA and 35.32 months for LITT. In paired comparison, a significant difference could be detected between MWA versus RFA (p?=?0.032). The progression-free survival showed a median of 23.49?±?0.62 months for MWA,19.88?±?2.17 months for LITT and 16.66?±?0.66 months for RFA (p?=?0.048). The lowest recurrence rate was detected in lesions ablated with MWA (7.7%; 8 of 104 lesions) followed by RFA (20.4%; 10 of 49 lesions) and LITT (27.3%; 6 of 22 lesions) p value of 0.012. Pneumothorax was detected in 22.16% of MWA ablations, 22.73% of LITT ablations and 14.23% of RFA ablations.

Conclusion: LITT, RFA and MWA may provide an effective therapeutic option for non-colorectal cancer lung metastases with an advantage for MWA regarding local tumour control and progression-free survival rate.     

Safety margin after radiofrequency ablation of hepatocellular carcinoma: precise assessment with a three-dimensional reconstruction technique using CT imaging

Purpose: To analyse the precise ablative margin (AM) after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) and the correlation between AM and local tumour progression (LTP) with a three-dimension (3D) reconstruction technique.

Methods: From March 2011 to May 2013, 134 patients who underwent RFA for 159 primary or recurrent HCCs within Milan criteria were enrolled. Contrast-enhanced computed tomography (CECT) scans were performed 1?week before and 1?month after treatment. The AM was measured in various directions using a 3D reconstruction technique that shows the index tumour and ablated zone on the same image. The average of all obtained AMs (average AM) and the smallest AM (min-AM) were calculated.

Results: The min-AM after RFA ranged from 1 to 9.3?mm (median?±?standard deviation, 4.8?±?1.8?mm). LTP was observed in 19 tumours from 19 patients. The median min-AM was 3.1?±?1.6?mm for patients with LTP, while the median min-AM of patients without LTP was 5.1?±?1.8?mm (p?=?0.023). After RFA, the 1-, 2- and 3-year LTP rates were 10.9, 25.9 and 35.1%, respectively, for patients with min-AM <5?mm, and 4.1, 4.1 and 4.1%, respectively, for patients with min-AM ≥5?mm (p?=?0.016). Multivariate analysis showed that only min-AM <5?mm was an independent risk factor for LTP after RFA (p?=?0.044, hazard ratio =4.587, 95% confidence interval, 1.045–22.296).

Conclusions: The 3D reconstruction technique is a precise method for evaluating the post-ablation margin. Patients with min-AM less than 5?mm had a higher probability of developing LTP.     

Combined radiofrequency ablation and ethanol injection versus repeat hepatectomy for elderly patients with recurrent hepatocellular carcinoma after initial hepatic surgery

Purpose: To retrospectively compare the efficacy and safety of combined radiofrequency ablation and percutaneous ethanol injection (RFA–PEI) with repeat hepatectomy for elderly patients with initial recurrent hepatocellular carcinoma (HCC) after hepatic surgery.

Methods: From January 2009 to June 2015, 105 elderly patients (≥70?years) who underwent RFA–PEI (n?=?57) or repeated hepatectomy (n?=?48) for recurrent HCC?≤?5.0?cm were included in the study. The overall survival (OS) and recurrence-free survival (RFS) were analysed with the Kaplan–Meier method and compared by the log-rank test. Non-tumour-related death, complications and hospital stays were assessed. Univariate and multivariate analyses were performed to identify the prognostic significance of the variables in predicting the OS and RFS.

Results: OS rates were 78.2%, 40.8% and 36.7% at 1, 3 and 5?years after RFA–PEI and 76.3%, 52.5% and 42.6% after repeat hepatectomy, respectively (p?=?0.413). Correspondingly, the 1-, 3- and 5-year RFS rates after RFA–PEI and repeat hepatectomy were 69.5%, 37.8%, 33.1% and 73.1%, 49.7%, 40.7%, respectively (p?=?0.465). Non-tumour-related deaths in the RFA–PEI group (2/57) were significantly fewer than those in the repeat hepatectomy group (10/48) (p?=?0.016). RFA–PEI was superior to repeat hepatectomy regarding the major complication rates and length of in-hospital stay (both p?p?=?0.037) and RFS (HR?=?1.866, 95% CI?=?1.064–3.274, p?=?0.030).

Conclusion: RFA–PEI provides comparable OS and RFS to repeat hepatectomy for elderly patients with small recurrent HCC after hepatectomy but with fewer non-tumour-related deaths, major complications and shorter hospital stays.     

CT fluoroscopy-guided closed-tip catheter placement before regional hyperthermia treatment of soft tissue sarcomas: 5-Year experience in 35 consecutive patients

Purpose: This study was designed to assess technical success and complications in patients with high-risk soft tissue sarcomas undergoing CT fluoroscopy-guided closed-tip catheter placement before treatment with combined chemotherapy and regional hyperthermia. Materials and methods: This retrospective study comprised all patients referred for insertion of closed-tip catheters for the introduction of thermometry probes before regional hyperthermia treatment at a single university centre from 2010 to 2015. Catheter placements were performed under local anaesthesia and intermittent CT fluoroscopy guidance. Technical success, complication rate, duration of catheter insertion and dose–length product (DLP) were analysed. Technical success was defined as intratumoural catheter placement suitable for subsequent thermometry. Results: A total of 35 procedures were performed on 35 patients (22 men, 13 women). In 34 out of 35 interventions catheters were inserted successfully; in one patient catheter placement was not feasible. No intra-interventional complications occurred. In six patients post-interventional complications were observed – two major (one abscess formation and one severe catheter dislocation) and four minor complications. Technical failure was observed in 11.4% of patients, especially catheter kinking. A total of 55 catheters were placed, with a mean number of 1.7?±?0.7 per patient. Mean total DLP was 723.2?±?355.9 mGy*cm. Conclusion: CT fluoroscopy-guided closed-tip catheter placement into high-risk soft tissue sarcomas was characterised by high technical success and relatively low complication rate. While major complications were rarely observed, catheter-kinking preventing successful thermometry represented the most frequent technical failure.     

Percutaneous CT-guided radiofrequency ablation for unresectable hepatocellular carcinoma pulmonary metastases

Purpose: This study aimed to evaluate the safety and efficacy of percutaneous CT-guided radiofrequency ablation (RFA) for unresectable hepatocellular carcinoma pulmonary metastases (HCCPM) and to identify the prognostic factors for survival.

Materials and methods: We reviewed the medical records of 320 patients with HCCPM treated between January 2005 and January 2012. Among them, 29 patients with 68 lesions of unresectable HCCPM underwent 56 RFA sessions. Safety, local efficacy, survival and prognostic factors were evaluated. Survival was analysed using the Kaplan-Meier method. Univariate analyses were evaluated by the log-rank test.

Results: Pneumothorax requiring chest tube placement occurred in five (8.9%, 5/56) RFA sessions. During the median follow-up period of 23 months (range 6–70), 18 patients (62.1%, 18/29) died of tumour progression and 11 (37.9%, 11/29) were alive. The 1-, 2- and 3-year overall survival rates were 73.4%, 41.1% and 30%, respectively. The median progression-free survival was 18 months (95% confidence interval (CI) 9.8–26.2) and the median overall survival time was 21 months (95%CI, 9.7–32.3). The maximum tumour diameter ≤3?cm (p?=?0.002), the number of pulmonary metastases ≤3 (p?=?0.014), serum AFP level ≤400?ng/mL (p?=?0.003), and the controlled status of intrahepatic tumour after lung RFA (p?=?0.001) were favourable prognostic factors for overall survival.

Conclusions: Our study indicates that percutaneous CT-guided RFA, as an alternative treatment procedure to pulmonary metastasectomy, can be a safe and effective therapeutic option for unresectable HCCPM.     

Population-based matching comparison between radiofrequency ablation and percutaneous ethanol or acetic acid injection for hepatocellular carcinoma

BackgroundLoco-regional therapies are evolving for hepatocellular carcinoma (HCC) treatment. Radiofrequency ablation (RFA) has changed the landscape in treating HCC; however, percutaneous ethanol or acetic acid injection (PEI/PAI) remains a widely used and easily performed technique by experienced clinicians. Nevertheless, the effectiveness of RFA compared to that of PEI/PAI remains unclear.MethodsRecords of 73,136 patients with newly diagnosed HCC between 2007 and 2013 were drawn from the Taiwan Cancer Registry. The primary outcome measures were the overall survival and local recurrence-free survival. Propensity score matching (PSM) was performed to compare the effectiveness of RFA and PEI. Median follow-up time was 61.6 months (36–120 months).ResultsAfter PSM, 4496 patients diagnosed with stage I-III HCC, who were initially treated with RFA (3372 patients) or PEI/PAI (1124 patients), were assessed. Compared to PEI/PAI, patients treated with RFA had better 5- and 9-year overall survival, cancer-specific survival, disease-free survival, and local recurrence-free survival. Median overall survival and recurrence-free survival of patients treated with RFA vs PEI/PAI were 61.5 vs 41.9 months and 72.1 vs 45.2 months, respectively. Multivariate Cox model analysis revealed that, except for patients with high cell grade or advanced stage, RFA resulted in better overall survival (HR: 0.74, 95% CI 0.68–0.81, P < 0.001) and local recurrence-free survival (HR: 0.69, 95% CI 0.63–0.75, P < 0.001) than PEI/PAI.ConclusionsRFA provides advantages over conventional PEI/PAI for HCC. Considering technological advances in instruments, loco-regional therapies for HCC can be employed in carefully selected patients.     

Effect of thermal dose on heat shock protein expression after radio-frequency ablation with and without adjuvant nanoparticle chemotherapies

Purpose: The aim of this study was to evaluate the effect of different radio-frequency ablation (RFA) thermal doses on coagulation and heat shock protein (HSP) response with and without adjuvant nanotherapies.

Materials and methods: First, Fischer rats were assigned to nine different thermal doses of hepatic RFA (50–90?°C, 2–20?min, three per group) or no treatment (n?=?3). Next, five of these RF thermal doses were combined with liposomal-doxorubicin (Lipo-Dox, 1?mg intravenously) in R3230 breast tumours, or no tumour treatment (five per group). Finally, RFA/Lipo-Dox was given without and with an Hsp70 inhibitor, micellar quercetin (Mic-Qu, 0.3?mg intravenously) for two different RFA doses with similar coagulation but differing peri-ablational Hsp70 (RFA/Lipo-Dox at 70?°C × 5?min and 90?°C × 2?min, single tumours, five per group). All animals were sacrificed 24?h post-RFA and gross tissue coagulation and Hsp70 (maximum rim thickness and % cell positivity) were correlated to thermal dose including cumulative equivalent minutes at 43?°C (CEM₄₃).

Results: Incremental increases in thermal dose (CEM₄₃) correlated to increasing liver tissue coagulation (R² = 0.7), but not with peri-ablational Hsp70 expression (R² = 0.14). Similarly, increasing thermal dose correlated to increasing R3230 tumour coagulation for RF alone and RFA/Lipo-Dox (R² = 0.7 for both). The addition of Lipo-Dox better correlated to increasing Hsp70 expression compared to RFA alone (RFA: R² = 0.4, RFA/Lipo-Dox: R² = 0.7). Finally, addition of Mic-Qu to two thermal doses combined with Lipo-Dox resulted in greater tumour coagulation (p?<?0.0003) for RFA at 90?°C × 2?min (i.e. greater baseline Hsp70 expression) than an RFA dose that produced similar coagulation but less HSP expression (p?<?0.0004).

Conclusion: Adjuvant intravenous Lipo-Dox increases peri-ablational Hsp70 expression in a thermally dependent manner. Such expression can be exploited to produce greater tumour destruction when adding a second adjuvant nanodrug (Mic-Qu) to suppress peri-ablational HSP expression.     

Diagnostic imaging for suspected pulmonary embolism during pregnancy and postpartum: A comparative radiation dose study

Introduction

To compare the radiation dose exposure and diagnostic efficiency of computed tomographic pulmonary angiography (CTPA) and ventilation/perfusion imaging (V/Q) for clinically suspected pulmonary embolism (PE) in pregnant and postpartum women in a tertiary hospital setting.

Methods

A retrospective cohort study of 473 pregnant and postpartum women referred for CTPA or V/Q for clinically suspected PE between January 2013 and December 2018 at a tertiary hospital. Maternal effective radiation dose, breast-absorbed radiation dose and fetal-absorbed dose estimates were calculated. Diagnostic yield was evaluated from radiological findings.

Results

Computed tomographic pulmonary angiography (CTPA) was more commonly used for the imaging of suspected PE in pregnant and postpartum populations (51.9% vs. 48.1% and 77.1% vs. 22.9%, respectively). CTPA was associated with higher maternal effective and breast-absorbed doses (maternal effective CTPA 4.7 (±2.9) mSv (millisievert), V/Q 1.7(±0.8) mSv (mean difference 2.93 mSv P < 0.001), and breast-absorbed CTPA 8.0 (±5.2) mGy (milligray), V/Q 0.3 (±0.1) (mean difference 7.67 mGy P < 0.001), respectively). Fetal radiation dose exposure was low. The incidence of positive PE was 5.5%. Indeterminate rates of CTPA and V/Q were 3.0% and 5.5% (P = 0.176), respectively.

Conclusions

Compared to V/Q, CTPA is associated with higher maternal and breast radiation dose; however, modern CT scanners achieve lower radiation doses than historically described. Fetal radiation dose was comparably low. The diagnostic yield of the imaging modalities in pregnant and postpartum women is similar. Revision of guidelines should occur with the advances in CT technology.     

Bipolar radiofrequency ablation of benign thyroid nodules using a multiple overlapping shot technique in a 3-month follow-up

Purpose The aim of this study was to evaluate the decrease of benign thyroid nodules after bipolar radiofrequency ablation (RFA) in a 3-month follow-up using a multiple overlapping shot technique (‘MOST’).

Methods A total of 18 patients with 20 symptomatic benign thyroid nodules (17 cold nodules, 3 hyperfunctioning nodules) were treated in one single session by bipolar RFA. Bipolar ablation was performed using MOST. The nodule volumes were measured prior to ablation and 3 months after the procedure using ultrasound. The population consisted of either solid (>80% solid tissue within the volume of interest), complex, or cystic nodules (<20% solid tissue within the volume of interest).

Results Bipolar RFA resulted in a highly significant (p?<?0.0001) decrease of nodule volume (ΔV), median 5.3?mL (range 0.13–43.1?mL), corresponding to a relative reduction in mean of 56?±?17.9%. Median initial volume was 8?mL (range 0.48–62?mL); 3 months after ablation a median volume of 2.3?mL (range 0.3–32?mL) was measured. Nodule growth ≥50% occurred in 70% (14 nodules). At the follow-up no complications such as infections, persisting pain, nerve injuries or immunogen stimulation occurred. Patients with cold nodules (15) remained euthyroid, with hyperfunctioning nodules either euthyroid (2) or latent hypofunctional (1).

Conclusion The use of bipolar RFA is an effective, safe and suitable thermoablative technique to treat benign thyroid nodules. Combined with the multiple overlapping shot technique it allows sufficient ablation.     

Abdominal pediatric cancer surveillance using serial computed tomography: evaluation of organ absorbed dose and effective dose

Computed tomography (CT) is used extensively in cancer diagnosis, staging, evaluation of response to treatment, and in active surveillance for cancer reoccurrence. A review of CT technology is provided, at a level of detail appropriate for a busy clinician to review. The basis of x-ray CT dosimetry is also discussed, and concepts of absorbed dose and effective dose (ED) are distinguished. Absorbed dose is a physical quantity (measured in milligray [mGy]) equal to the x-ray energy deposited in a mass of tissue, whereas ED uses an organ-specific weighting method that converts organ doses to ED measured in millisieverts (mSv). The organ weighting values carry with them a measure of radiation risk, and so ED (in mSv) is not a physical dose metric but rather is one that conveys radiation risk. The use of CT in a cancer surveillance protocol was used as an example of a pediatric patient who had kidney cancer, with surgery and radiation therapy. The active use of CT for cancer surveillance along with diagnostic CT scans led to a total of 50 CT scans performed on this child in a 7-year period. It was estimated that the patient received an average organ dose of 431 mGy from these CT scans. By comparison, the radiation therapy was performed and delivered 50.4 Gy to the patient's abdomen. Thus, the total dose from CT represented only 0.8% of the patient's radiation dose.     

The safety and efficacy of microwave ablation for the treatment of CRC pulmonary metastases

Purpose: Microwave ablation (MWA) is a recently developed thermal ablation technique that has been used for the treatment of different types of tumours. In the present study, we retrospectively evaluated the safety and efficacy of CT-guided percutaneous MWA for the treatment of colorectal cancer (CRC) pulmonary metastases.

Materials and methods: From June 2010 to June 2015, 48 unresectable lesions in 32 patients with CRC pulmonary metastases were subjected to CT-guided MWA. Imaging follow-up was with contrast-enhanced CT and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT.

Results: Oncologic imaging showed that 42 (87.5%) of the 48 lesions in the 32 patients were completely ablated. Needle track metastatic seeding was not found, and no patient deaths occurred within 30?d after ablation. The mean hospital stay was 3?d (range, 2–7?d). Pneumothorax was the most frequent complication and occurred in 6 (12.5%) of the 48 lesions. The median survival time was 31?months (95% CI: 15.4–46.6). The 1-, 2- and 3-year survival rates were 79.5%, 63.1% and 44.4%, respectively. Univariate Cox regression analysis showed that tumour size, disease-free interval (DFI) and number of tumours were significantly related to the overall survival time (p?=?.007, p?=?.022 and p?=?.030, respectively). Multivariate analysis showed that tumour size was an independent prognostic factor for survival (p?=?.017).

Conclusion: CT-guided percutaneous MWA is a safe and effective minimally invasive method for treating CRC pulmonary metastases.     

Radiofrequency ablation versus surgical resection for hepatocellular carcinoma within the Milan criteria: A study of 281 Western patients

Abstract

Objectives: The aim of this study was to compare survival between radiofrequency ablation (RFA) and surgical resection (SR) in patients with hepatocellular carcinoma (HCC) within Milan criteria. Methods: From January 2004 to December 2013 we consecutively and retrospectively included all patients with first occurrence of HCC within Milan criteria receiving SR or RFA as first-line treatment. The cumulative overall survival (OS) and disease-free survival (DFS) were compared after inverse probability weighting (including confounding factor). Results: A total of 281 patients (RFA 178, SR 103) were enrolled. In multivariate Cox regression RFA and SR were not independent predictors of survival or recurrence. The respective weighted 5 years OS and DFS for patients with propensity scores between 0.1–0.9 in the SR and RFA groups were 54–33% and 60–16.9%, P?=?0.695 and P?=?0.426, respectively. Local tumour progression rate did not differ according to treatment (P?=?0.523). Major complication rate was higher in the SR group, P?=?0.001. Hospitalisation duration was lower in the RFA group (mean 2.19 days, range 2–7) than in the SR group (mean 10.2 days, range 3–30), P?<?0.001. Conclusion: This large Western study has shown that OS and DFS did not differ after RFA (using mainly multipolar devices) and SR, for HCC within the Milan criteria in a European population, with a shorter hospitalisation time and a lower complication rate for RFA.     

Is routine pelvic surveillance imaging necessary in patients with Wilms tumor?

BACKGROUND:

It is unclear whether routine pelvic imaging is needed in patients with Wilms tumor. Thus, the primary objective of the current study was to examine the role of routine pelvic computed tomography (CT) in a cohort of pediatric patients with Wilms tumor.

METHODS:

With institutional review board approval, the authors retrospectively identified 110 patients who had Wilms tumor diagnosed between January 1999 and December 2009 with surveillance imaging that continued through March 2011. The authors estimated overall survival (OS), event‐free survival (EFS), and dosimetry from dose length product (DLP) conversion to the effective dose (ED) for every CT in a subgroup of 80 patients who had CT studies obtained using contemporary scanners (2002‐2011). Metal‐oxide‐semiconductor field‐effect transistor (MOSFET) dosimeters were placed within organs of anthropomorphic phantoms to directly calculate the truncal ED. ED_DLP was correlated with ED_MOSFET to calculate potential pelvic dose savings.

RESULTS:

Eighty patients underwent 605 CT examinations that contained DLP information, including 352 CT scans of the chest, abdomen, and pelvis; 123 CT scans of the chest and abdomen; 102 CT scans of the chest only; 18 CT scans of the abdomen and pelvis; 9 CT scans of the abdomen only; and 1 CT that was limited to the pelvis. The respective 5‐year OS and EFS estimates were 92.8% ± 3% and 2.6% ± 4.3%. Sixteen of 110 patients (15%) developed a relapse a median of 11.3 months (range, 5.0 months to 7.3 years) after diagnosis, and 4 patients died of disease recurrence. Three patients developed pelvic relapses, all 3 of which were symptomatic. The estimated ED savings from sex‐neutral CT surveillance performed at a 120‐kilovolt peak without pelvic imaging was calculated as 30.5% for the average patient aged 1 year, 30.4% for the average patient aged 5 years, 39.4% for the average patient aged 10 years, and 44.9% for the average patient aged 15 years.

CONCLUSIONS:

Omitting pelvic CT from the routine, off‐therapy follow‐up of patients with Wilms tumor saved an average 30% to 45% of the ED without compromising disease detection. Cancer 2013. © 2012 American Cancer Society.     

Early Results of Lung Cancer Screening and Radiation Dose Assessment by Low-dose CT at a Community Hospital

Background

The National Lung Screening Trial showed a reduction in overall and cancer-specific mortality for patients screened with low-dose computed tomography (LDCT) versus chest radiograph. Some question whether this can be achieved in community healthcare settings. Our aim was to analyze lung cancer screening outcomes and administered radiation dose using LDCT scans at a community hospital.

Evaluation of Ultra-low-dose Paediatric Cone-beam Computed Tomography for Image-guided Radiotherapy

AimsIn image-guided radiotherapy, daily cone-beam computed tomography (CBCT) is rarely applied to children due to concerns over imaging dose. Simulating low-dose CBCT can aid clinical protocol design by allowing visualisation of new scan protocols in patients without delivering additional dose. This work simulated ultra-low-dose CBCT and evaluated its use for paediatric image-guided radiotherapy by assessment of image registration accuracy and visual image quality.Materials and methodsUltra-low-dose CBCT was simulated by adding the appropriate amount of noise to projection images prior to reconstruction. This simulation was validated in phantoms before application to paediatric patient data. Scans from 20 patients acquired at our current clinical protocol (0.8 mGy) were simulated for a range of ultra-low doses (0.5, 0.4, 0.2 and 0.125 mGy) creating 100 scans in total. Automatic registration accuracy was assessed in all 100 scans. Inter-observer registration variation was next assessed for a subset of 40 scans (five scans at each simulated dose and 20 scans at the current clinical protocol). This subset was assessed for visual image quality by Likert scale grading of registration performance and visibility of target coverage, organs at risk, soft-tissue structures and bony anatomy.ResultsSimulated and acquired phantom scans were in excellent agreement. For patient scans, bony atomy registration discrepancies for ultra-low-dose scans fell within 2 mm (translation) and 1° (rotation) compared with the current clinical protocol, with excellent inter-observer agreement. Soft-tissue registration showed large discrepancies. Bone visualisation and registration performance reached over 75% acceptability (rated ‘well’ or ‘very well’) down to the lowest doses. Soft-tissue visualisation did not reach this threshold for any dose.ConclusionUltra-low-dose CBCT was accurately simulated and evaluated in patient data. Patient scans simulated down to 0.125 mGy were appropriate for bony anatomy set-up. The large dose reduction could allow for more frequent (e.g. daily) image guidance and, hence, more accurate set-up for paediatric radiotherapy.     

Iterative treatment with surgery and radiofrequency ablation of uveal melanoma liver metastasis: Retrospective analysis of a series of very long-term survivors

BackgroundAfter treatment of primary ocular uveal melanoma (UM), up to 50% of patients will develop metastases, mostly in the liver. Systemic treatments do not provide any overall survival benefit for these patients and surgery remains the most effective therapy for selected patients. Radiofrequency ablation (RFA) alone or in combination with surgery is frequently used to spare hepatic parenchyma. When patients relapse after treatment of their first metastases, and when the liver recurrence is limited, new local liver treatment is questionable.MethodsA total of 14 patients with liver metastases from uveal melanoma (LMUM) were retrospectively evaluated. All patients had a complete first liver resection and a second treatment with RFA. Overall survival, recurrence-free interval after the first and the second treatment was evaluated.ResultsTreatment of hepatic recurrence was percutaneous RFA for ten patients and per-operative RFA for four patients associated with new metastasectomy. The median time to onset of LMUMs after ocular UM treatment was 50 months, and the median time to recurrence of hepatic metastasis after the first liver treatment was 20 months. The overall survival was 70% at five years and 35% at ten years. The recurrence-free interval was 50% and 56% at two years after the first and the second treatment, respectively.ConclusionProlonged survival can be achieved by exclusive and iterative local treatment combining surgery and RFA in a small proportion of patients with a first recurrence of isolated LMUM.